A full system example from Victron. It looks intimidating at first, but if we take our time and understand the basic concepts, it’s actually quite approachable—kudos to Victron. That said, it’s our responsibility to make sure that our installation is safe and conforms to the standards for the country our boat is flagged in. And further, I would modify this system to get rid of the engine start battery alternator and charge the start battery through a DC/DC charger.
The release of the new Victron NG Smart Lithium Battery, that I wrote about a few days ago, got me musing about where we have got to with lithium batteries generally. Here’s how I see the state of play through the lens of my own experience.
I’ll fully agree with you, John, about the advantages of mature, single-vendor, fully-integrated systems often justifying their additional expense. That opinion comes from decades of experience as a software engineer. I’m also now an Apple guy, not only for employer-supplied hardware, but also for my personal needs. That approach affords me more time to concentrate on things I should instead of on endless technical distractions.
I’m not entirely with you on the maturity of the batteries themselves, however. There are still significant changes in battery technology that are in process, driven largely by the electric vehicle market. That means that enticing new batteries will continue to come out for some time, but they often won’t be able to be integrated immediately into single-vendor systems without compromises or giving up some of the advantages of those fully-integrated systems. Right now, I am thinking about the enticement of lighter, safer solid state lithium batteries like those from Solid State Marine, but I am confident that there will be more examples in the future as battery technology continues to evolve.
One last note: There’s another reason to wait a bit on the Victron NG batteries. The current Victron data sheet shows that the UL and IEC safety certifications are still pending on half of the new battery models, so it may make sense to boaters and insurers to wait until those are completed.
I think the difference here is one of semantics. I don’t equate maturity with the end of innovation. For example I have considered the Apple system mature for at least 10 years even though they made the huge change to their own chips about five years ago. To me what makes Apple mature is that they were able to make that change smoothly.
As to UL approval, sure, that’s always the case. Getting all these approvals is time consuming and expensive and must be done for every new model but I don’t think it’s significant to the question of maturity. Also I think it’s way past time that ABYC recognized European standards. We have some of the same proprietary standards issues in Canada, for example for MOB beacons, and it’s just silly and causes unnecessary friction and expense.
Anyway, are you sure ABYC requires UL on the batteries? I have not checked that. And if they do let’s not forget there is a whole world out there that includes the majority of AAC readers that uses other standards, many of them actual standards, (rather than industry guide lines) with the weight of law behind them.
ABYC standard E-13 for lithium batteries requires lithium batteries or cells to meet the testing requirements of at least one of the following standards: IEC 62133, IEC 62619, IEC 62620, SAE J2929, UL1642, UL1973, or UL 2054.
Note the expression “meet the testing requirements of,” which ABYC uses in many standards. A manufacturer could satisfy the ABYC requirement by paying an independent lab to test a product according to UL protocols without actually going through the expensive and onerous process of acquiring and maintaining UL listing.
ABYC E-13 was under review this year. The updated standard should be out this month. It will be interesting to see what has changed.
Thanks, you saved me wading through E10 and 13. I must have read each at least four times over the years, but although my memory is still good at 74, it doesn’t last as long.
And yes, I’m looking forward to the new version of E13, particularly since I was rather disappointed with the first go around.
First, I didn’t mention anything about ABYC requirements. While ABYC E-13 does reference the UL and IEC standards that Victron lists as certification pending for half of the NG batteries, I’m simply saying that waiting for the products to complete those safety certifications may make sense to provide better defense against a claim denial on the grounds that installed batteries were unsafe. It’s just more weight behind your already present recommendations to delay using an NG system on other grounds.
Second, IEC 62619 is a harmonized European standard (an EN-IEC standard). Curiously, Victron’s CE Mark certification lists EN IEC 62619:2022 even though the product data sheet shows IEC 62619 as pending for half the products listed in the CE certificate. I don’t know what the full story is on that, but again, seeking clarity on such safety certifications can be a legitimate additional reason to delay.
On the battery maturity issue, I think you’ve missed the point a bit. Yes, an integrated system developer will typically further integrate their own innovations in a timely fashion (as Apple did with their own chips and Victron did with their own battery management technology); but with marine batteries we should still be expecting significant and even rapid technological development from other companies than Victron or Mastervolt. Those third-party products often won’t be integrated in a timely fashion (if at all) into the fully-integrated ecosystems. In a regime of rapid, ongoing technological development, going with a fully-integrated vendor’s system often will preclude using third-party products that incorporate significant technological and functional advances.
Being a step or two behind the bleeding edge doesn’t mean that the integrated product lines are useless or don’t provide value and quality service. But it is just another compromise to be aware of when choosing to go with an end-to-end, integrated-system vendor.
I agree with all that, but don’t understand why any of it caused you to suggest that I was wrong that lithium was mature. Any mature product can be disrupted by an innovation. For example lead acid batteries are mature technology but are rapidly getting obsoleted by lithium (for many uses).
What’s next after lithium? Beats heck out of me, but there will be something and if I had to guess it will be something none of us have thought about…but I could be wrong. So sure, we could buy a full Victron NG system today and have it totally obsoleted by something new next year, but that does not alter that the Victron system was mature and a good buy at the time, and perhaps for many years afterward, just as lead acid was the best bet for most of us for at least a decade after lithium boat batteries.
I would also suggest (again) that you couch your comments more carefully. Starting by telling me I missed the point, was unfortunate. Missed my point would have been better and I find it better still to start with “perhaps I was not clear”. That may sound pedantic but it’s little details like that the contribute to the collegial atmosphere at AAC—I have taken years to learn this, and still make mistakes.
Perhaps the issue is that “lithium battery” isn’t precise, nor is it limited to liquid electrolyte LiFePO4 batteries. What’s next after those LiFePO4 batteries is already pretty clear: the solid state lithium batteries that are becoming well-established in applications like electric vehicles and drones, and are starting to emerge as marine batteries. It’s analogous to the difference between flooded lead-acid and AGM batteries, but the solid state lithium chemistries are and will be a little further apart from current LiFePO4 batteries than the difference in battery chemistry between flooded and AGM lead acid batteries. To push the analogy a bit further, Victron’s “Next Generation” lithium batteries are like coming out with a new flooded lead-acid battery when AGM was poised to take over the market. They’ll still work, but Victron’s NG batteries are not the new hotness in lithium batteries, and do not feature the significantly greater charge and discharge rates as well as improved safety at half the weight that solid state lithium does. With Victron’s NG batteries only newly on the market, it is likely to be years before Victron offers fully-integrated solid state lithium batteries.
Ignat Fialkovskiy
July 27, 2025 7:22 pm
Hi John
On many occasions you put insurability and compliance with some standards on the top of the priority list. At the same time neither one of them is in itselve equivalent to good seamanship.
The in surability has actually nothing to do with seamanship, and standards, well, they must be un derstood and checked too. Being insured and fully complaint will not help al sea.
Good point, it would have been better to make seamanlike a separate bullet at the top. That said, I do write further up the Tip:
As far as I know, they are the only two who fully control their ecosystem and so can deliver systems that go together reasonably simply and deliver seamanlike reliability.
Peter Johnstone
July 28, 2025 9:12 am
The Mastervolt Lithium batteries have been around for over a decade and have redundant internal BMS systems…they have stood the test of time. I would give any new systems 3-5 years before using.
However in the case of Victron my thinking is that this is simply an evolution of their product line, so six months to a year delay works…I’m also a total Victron fan boy because there stuff has just worked for me.
Also, as a general rule I prefer external BMSs, so I really like that with Victron NT we can have that with automatic fail safe backup. That said, I can also see the benefits of the Mastervolt approach which is, I think, better than most internal BMSs.
Whitall Stokes
July 28, 2025 10:11 am
Hi John,
The M&R 56 now has an integrated Victron system with DC/DC to charge start battery and high output alternator for house. It’s been amazing.
Great to hear, and that it’s working well. What bank size did you go with and did you add any solar? If I had kept the boat I was going to add two flexible panels to the ridged Bimini.
I added some loads: washer/dryer, watermaker, Starlink, and wanted optionality for electric cooking. House bank is 400AH @ 48v. Alternator is now 130A @ 48v with Wakespeed regulator.
All DC appliances remain at 12v (except fuel pump!) but with dual pole breakers. Had to deviate from Victron for the 48/12 converters as only Mastervolt had a suitable offering.
Start battery is the same AGM that doubles as the 12v service battery to absorb inductive loads and remains in float from the Mastervolt converter/chargers. They are bi-directional so accommodate the solar controllers to boost charge the house bank.
Added two 160W rigid panels on the bimini that leaves a foot path down the middle.
As an aside added a stray current continuous monitor along with your VDO stray current meter, but that is another topic for another day.
Wow that was quite a rewire job! I thought about duel breakers for years but always chickened out. What stray current monitor did you install? I have never heard of a continues one.
At the risk of comment thread drift: https://selcousa.com/product/kpm169/
Monitors resistance between hull and DC neg. Alarm goes to N2K network. Too bad it’s so ugly.
Bob Hodges
July 28, 2025 10:21 am
Great article with useful logic and advice presented here. Is the system flow diagram available as a PDF (as it would be a great reference)?
I recently got a copy of the electrical schematic from Quorning Boats for a new Dragonfly 32 which had a Victron lithium battery system and the design elements are very similar if not identical to what is presented here.
Bob
Coincendantally enough I bookmarked that exact schematic just last Friday.They have a LOT of schematics available depending on the application. I believe this one is the “Genless monohull…”
Low temperature charging put me off lithium for a long time. But I just switched, mostly because my LA gave out due to age. And boy was the installation weight better! Only 6 months in, but so far so good.
Victron mentions a low temperature cut-off (sold separately).I did not see a provision for heating the batteries, as is done on Teslas. Granted, most sailors don’t cruise below freezing (but I suspect you may), but many keep boats in the water when battery temperatures could go below freezing, even with the buffering effect of seawater.
For me, a low temperature charging cut off was enough, since when it’s that cold I either stay ashore or day sail and forgo charging and power use both.
Thoughts? I would think a high latitude sailor would need a robust solution.
Hi Drew,
Many integrated LFP batteries have a heating element inside. If temps are too low, there’s apparently a relay that disconnects from charging and uses the incoming power from the charger to warm up the cells. When warm enough, the heating stops and the power goes into the cells. I assume this explanation is incomplete, as I have no personal experience with it, but I imagine it should be possible to DIY something similar too. Some resistive heating plates, a temp sensor and a relay…? I’ve not looked into it, but had it in the back of my mind for a while.
The problem with that system (I explored it) is that you must have considerable charging amps available, probably more than you have away from the dock.
If you are charging with solar it is low risk, because you are probably charging at a very low rate in the winter. My understanding is that LiFePO4 is not at significant risk at C<0.05 (about 20 hours to full charge). My solar charging C = 0.03 in full summer sun, but more realistically C<0.01 with the amps I actually see in the winter.
I guess I will report back after a few winters! I do go out when it is well below freezing. The greater concern is actually at the dock, because I do not plug in.
—
I do wonder if we will start hearing of problems from people who believe the lithium “drop-in” claims without reading the small print. I have heard (first hand reports of fellow F-boat owners) of problems with electronics getting fried by BMS disconnects. Basically, charging from a dumb source (outboard) and letting the battery regulate. That is not at ALL what you are discussing. In fact, I do not use my outboard as a charging source, in part because I don’t need to, in part because for a day sailor and occasional weekender the time is too short to contribute anything meaningful, and because I know it’s a dumb charging source.
Interestingly enough I never had cold issues with batteries and would probably would have been fine without heaters in lithium batteries. I never wintered over (on my own boat) except in Arctic Norway where we were plugged in and had plenty of heat. And when cruising in the summers I suspect the lithium batteries would have had a higher coldest temperature tolerance (+5 charging) than me and my crew! That said, I might have upped the insulation on the battery compartment. Seems to me that your solution should work since you could always sail and then return to the marina, warm the boat, and charge.
Stein Varjord
July 28, 2025 4:35 pm
Hi John,
I agree that Victron has reached maturity with their battery systems, and have proven that over more than a decade. I don’t know Mastervolt and Lithionics as well, but they’ve also proven knowledge for a long time.
Still, I don’t really feel that the lithium battery market is anywhere close to maturity. If consumers for some reason don’t pick the right brand(s), they’re pretty much in the same situation as several years ago. The product suppliers all claim great things, which usually contain several flat out lies.
I think there are too many traps and too many predators operating in the market, with not enough resistance. They exploit the opportunity given by the sticker shock from a full Victron system.
I think there’s still a place for the nerdy DIYer, who can now reliably get good cells and other components for a self build, or pick with skill among more integrated solutions with cheaper suppliers. If you’re not a nerd and can’t afford Victron, the “Rolls Royce”, it’s hard to avoid poor solutions.
Conclusion: The technology has reached maturity, and it’s available, but I think the market in general is still in a “wild west” state. The nerds are the gunslingers who can survive in the lawless environment. 🙂 The normal cruiser is still mostly being milked unfairly.
I agree. I guess we could say “Lithium Batteries are Mature” but the market is not. In my defence I do qualify maturity with a blue box pointing out that the installer (pro or owner) must know what they are doing.
Agreed. There are players in this market who have reached maturity. If you go to Victron, Mastervolt, or Lithionics, buy their stuff, and follow their directions, it will work as promised.
The market as a whole still has a lot of immature players.
This is very much akin to the state of other industries at this stage of development. The car industry has many mature players selling quality products with long-term support, but that didn’t stop people from being burned by buying a Fisker Ocean and then seeing the company and the parts supply chain disapper overnight.
Comments on other forums suggest that insurance companies (UK based) are not insuring DIY installation of lithium based systems unless signed off by a competent person and in some cases will only accept professional installation. I use the term “lithium” deliberately as there is no separation of battery types by insurance companies, as mentioned on the forum i.e. all lithium based batteries are lumped together. It is also suggested that there is now a reluctance by competent persons to sign off DIY with previous approvers now refusing. The forum in question is YBW/Practical Boat Owners Reader to Reader/Insurance for an Electric Yacht Conversion, dated Wednesday 30 July 2025. At least one contributor owns a coded boat (coded for commercial use) and as such will now not convert to LiFePO4 as it becomes cost prohibitive.
I’m sorry to hear that, although it does not come as a surprise. I took a brief look at the thread and it’s worth noting that this was a home brewed battery from cells and a BMS, not a full system that has passed certifications like the Victron. Given that, I don’t really blame the insurance company. Sure, a safe battery could be built by an amateur, but how on earth would any insurance company assure themselves of that?
Roman Puhek
July 28, 2025 6:25 pm
Very interesting read.
I’d like to share my experience on Victron NG package.
I switched from 4 AMG 200Ah Victron batteries to 2 200Ah LFP NG victron batteries just 3 weeks ago.
I asked professionals to do the upgrade as I had other things to do.
I enede up with:
2 ng LFP batteries
1 bus
1 bms
1 distributor
2 Orion DC2DC chargers (to limit and adjust the alternator output)
1 battery protect box
Today my son did started to lower the anchor and in an instant the whole boat lost 12V power. I lost all 12V powered devices including windlass and VHF. I guess he pressed to many buttons.
This happened few hours before the predicted major storm in Croatia.
I was luckily able to fix the problem within one hour, with a hanging hook on 20m of released chain floating in the harbour.
The problem was the battery protect box which failed. I bypassed it and everything started to work.
Additionally:
the 2 Orions are overheating after 5 minutes of charging the batteries from the alternator. It is just a warning I get. They continue to work.
my multiplus inverter/charger is too old to be upgraded tov support DVCC, so I’m getting this warning all the time.
My personal conclusion:
I believe I made a mistake by upgrading to NG everything integrated super duper system from Victron. I should have taken the time to take a closer look before the installation. Its functionality is a downgrade to what I had before (my alternator now charges the batteries much slower), I have a boat full of new shiny boxes and new cables and it cost my crazy amount of money not for batteries only but for all other super integrated boxes I had to buy.to get 2 batteries installed. If I could I would go back to my good olg AGMs and then do a proper simple upgrade to LFP nonintegrated much more reliable and cheaper system that would actually work.
I would advise people to take a good look at the LFP system before they upgrade and I would actually suggest to look away from Victron as sad as that sounds.
Hi Roman,
I’m sorry for your bad experience and hope you can figure out a way to improve the situation. I know far too little about your problem to be able to give any meaningful advice, of course. Still, if I were to speculate, I’d point to the people doing the installation.
I have many decades of experience with boating. I’ve also worked much in the business and now I’m a pro skipper and do some tech on electric canal boats. My qualifications: I can figure out things and I’m not too clumsy… Is that enough? Well… There are no real rules or limitations. I’ve seen so much plain stupidity I’ve stopped being shocked.
No “pro” boat tech is allowed to touch my boat. There are some amazingly good boat tech people, but they are about as easy to find as unicorns. My respect for leisure boat professionals in general is on par with lawyers and used car sales persons.
The people installing the new shiny lithium tech, no matter what brand they push, are most likely of the above described quality. They are most likely totally incompetent, and don’t even know themselves how bad they are. Google “Dunning-Kruger”. No matter how good components they use, they will sabotage the system as a whole, since they have no idea how it works.
Victron make products that are simple to install, if compared to the competition, but that doesn’t mean it’s actually simple and doesn’t need proper knowledge. It can’t be “winged”. The correct components must be chosen, they must be connected right and be programmed right. I think you have become another victim to what I described in a previous comment, the “wild west” attitudes in the lithium for boats market. We need good products AND good people.
The bottom line is that lithium systems have more to go wrong, and therefor a failure is more likely than with lead acid, so a backup system is pretty much required to be seamanlike.
As to your specific issues:
Both Victron, and here at AAC we, recommend that the service batteries should be charged directly from the alternator with an intelligent charge controller that can respond to commands from the BMS (Wakespeed WS5000 is our recommendation) and the engine battery charged via DC/DC. That will solve your Orion over heat issue and allow you to get the most out of your alternator. More on that here: https://www.morganscloud.com/2022/09/04/battery-bank-separation-and-cross-charging-best-practices/
If the charger is too old for DVCC it should probably be replaced and the installer should have warned you of this. It’s fundamental to a reliable lithium system that all charging sources need to be under control of the BMS, That said it may be possible to hack this using the allowed to charge output on the BMS. Worth checking in the charger manual if it has a input contact to tell it to stop charging.
It probably would, as I warn above, have been better to wait a bit before installing a brand new product. That said, I don’t think that’s the core of the issue.
I fear Stein is right about the core of the problem.
Thank you Stein and John.
I’m sorry for a bit bitter context of my post. I posted it one hour after I solved the issue and was in gentle Victron “killing mode”.
I agree with what both of you said above.
I will certainly be much more careful and hands on when I upgrade my other boat.
Upgraded alternator with capable regulator would be my choice. It certainly is the way to go. And it would actually be cheaper, more stable and better overall.
Some kind of smaller backup 12v system would be very reasonable at least for critical systems like VHF (so I could call for help).
The thing that bothers me is the failure of Battery protect module. It crashed. The simplest part of the installation was the cause for the problems. In my opinion it is also overkill for my installation and will not use it in future.
Victron should make sure that my scenario can not happen.
I can imagine novice owners of new boats with Victron NG by the book installation ending up in my situation. They would be very lucky not to cause damage to their and other boat, if not altogether beaching it in the middle of the storm.
I agree blackouts are dangerous, but I really can’t see how Victron could build a system that make them impossible. After all blackouts ocure on lead acid boats too, but less often because lead acid is so much simpler with almost nothing to go wrong between the battery and the load. But that’s simply not possible with Lithium because it’s intrinsically fragile and therefore requires all kinds of complex stuff to protect the cells inserted between the load and the battery. Bottom line, I just can’t think of any way to have a totally blackout proof lithium system other than the serial backup we suggest. The good news is that’s pretty easy and cheap to do, and can power way more than just a VHF, or at least have a switch to move other vital loads in seconds. All detailed here: https://www.morganscloud.com/2022/07/03/building-a-seamanlike-lithium-battery-system/
I got interested in this and read the manual for the battery protect. It may be that it failed, but it’s also a very real possibility that the tech who installed the system did not program it properly in lithium mode. I’m guessing this because it cut out when your son activated the windlass which would cause a sudden drop in voltage.
In lithium mode the battery protect is actually controlled by the BMS but if the tech did not run that control lines from the lynx AND use bluetooth to change the battery protect into lithium mode that’s exactly what would happen, particularly if any wiring was undersized or there was a bad contact anywhere.
Hi John,
I think you’re spot on. I was also wondering if the Victron Battery Protect is a good choice for this setup. It’s a diode based item, meant for more “stupid” systems that might need what the name describes. In a battery system that has a high tech BMS, that seems like strange choice, but I haven’t looked properly at it, so I might be wrong.
You do want some means in a Victron Lynx BMS system to cut off battery loads while chargers remain connected. Otherwise the contactor in the BMS may open, disconnecting everything.
True, and that would leave the charging sources connected so we could switch one on immediately to solve the problem, without screwing around to get the Lynx reset.
I too have wondered about the reason for the Battery Protector in a system with a Lynx BMS. That said Victron clearly shows them in their recommended layout so I guess they must think it necessary. Some time, probably this winter, I need to take a deep dive into the manuals to understand the issues and tradeoffs better.
It was my thought as well that the Battery Protect could be exposing a problem with excessive voltage drop under load rather than itself being the cause of the problem. A dumber electrical system may continue to work while the problem remains hidden, but that isn’t the same thing as there being no problem.
Steve Ferguson
July 29, 2025 1:05 am
Hello John, I am interested in the Victron lithium battery lay out.
Unfortunately the resolution of the drawing is insufficient to let me read the text when the image is enlarged.
Would it be possible to send me a link to the original file?
Regards Steve Ferguson. Tasmania, Australia.
Loving the AAC website.
While predating Lithium NG, for anyone looking to understand the big picture of electrical systems, I would recommend the Marine System Booklet. It took me a good while to independently end up exactly with the system labeled “An inverter/charger system being monitored via Bluetooth and the VictronConnect app, via the VE.Bus Smart dongle.”
I fully agree with the article. Tone of voice -wise I find John should perhaps be more honest about his inner geek. Us geeks often choose Apple even if we would know how to configure and build a PC.
My issue with the Victron universe is that they typically only have one BMS controlling the paralleled batteries. Granted, the Lynx uses a (supposedly superior) mechanical contactor, but doesn’t this disconnect both charge AND load if there’s a fault condition detected? That’s why I’m looking hard at the Epoch Elite batteries, each with a very well designed and integrated BMS. As for the MOSFET v. Contactor debate, mechanical contactors are not impervious to failure. Well-built MOSFETs with the proper amperage rating seem reliable enough, especially in a system with 2 or 3 BMS’s in parallel. I’m sure there are bad MOSFETs, and good, the same with contactors.
Brian on Helacious, currently West coast of Iceland
Hi Brian,
I’m no electrical engineer, but AIFK the problem with diodes isn’t primarily reliability, it’s their failure modality. I’ll probably use some non pro terminology, but I hope it makes sense:
They fail to closed, meaning they let the power flow freely. That can be pretty catastrophic…
Relays for this type of use are “normally open” type, which need a small control current to move from open to closed. If anything goes wrong, no matter what, it fails to open, breaking the connection.
To me, this seems like a must have property, making diodes a dealbreaker in this function. On top of this core flaw, diodes have a strict limit on current, which will severely limit the capacity the cells have, and diodes cause Voltage drop etc. So they eat power. To me it makes sense that the high end companies only use relays for this.
I hear you on this, but aside from the excellent point that Stein makes there is also a far from obvious architectural difference between the two options: A battery like the Epoch needs two busses because it has no way to control all the charging sources so it has no alternative but to disconnect the charge buss from the cells and by having two busses it can leave the loads supplied. All good, but the problem is that any time we cut off a flowing DC current in that way we risk a voltage spike. We all think of this in connection with alternators, but it’s true, albeit to a lesser extent, of all charging sources, and spikes stress electronics over time, so this is not best practice, although it does work.
On the other hand in the Victron system the BMS directly controls all charging sources so rather than cutting them off, it just tells them to shut down elegantly with the batteries still connected. Therefore it does not need two busses because it’s not going to disconnect the batteries. The contactor is only there as a last line of defence in case something goes wrong and to satisfy regulation.
A good way to think of this is that the contactor is like a circuit breaker that will only activate when something has gone really bad, but the MOSFETS are part of general operation.
(To be fair, I seem to remember, (might be thinking of another product) that some of the Epochs also have contactors built in and also some Epochs can work with the Victron system to control charging sources. That said, by so doing we lose the benefits of buying from all one vendor and open ourselves to the horrors of parsing the finger pointing when something goes wrong. And as a guy who founded and ran a computer systems integrator building complete business computers with hardware and software from multiple vendors, trust me, it’s no fun! But at least I got paid well for it.)
The Epoch Elite can use Cerbo’s DVCC feature to control certain charging devices like the Blue Solar and the Multiplus. But not the Skylaa charger, and not the Wakespeed, apparently. C’mon, Epoch.
The Victron Smart Battery Protect devices that Victron shows in their diagrams are MOSFET devices. Their Lynx BMS uses these SPBs to control the day-to-day ATC (allow to charge ) or ATD (discharge) functions. The contactor in the Lynx is there as a failsafe backup. Wouldn’t the primary class T fuse protect against a catastrophic over-discharge situation? What is needed is a contactor to monitor and disconnect charging should the BMS’s MOSFETs (which are not actually diodes but sometimes behave like diodes) fail and a over-voltage (above 14.6vdc) situation occurs. What is that device? Basically we need a BMS for our built-in BMS’s! This is why I have avoided lithium for so long…
Thanks for the fill in the Elite, it’s just these kinds of complications that lead me to sticking with one vendor.
No a fuse won’t protect against over charge since a lithium battery will be trashed way before the fuse blows.
And yes, I understand what the Smart Protect do, although I would be the first to admit that without a really long dive into all the manuals, some of the details may escape me.
As to other things that the system may require or not, I guess I pretty much trust Victron to be getting these sample layouts right, so I’m not expending any brain sweat (or time when I could be sailing) on trying to second guess them.
And yes, I agree, lithium is complicated, and always will be because these batteries are fundamentaly fragile and therefore need a lot of stuff around them. Definitely not for everyone and no shame in saying “not for me”. Still, for those who want to take it on, I think today we can be pretty comfortable with a Victron or Mastervolt system, at least as long as we know what we are doing and don’t deviate from the recommended set ups.
Yes, batteries with integrated BMSs have a BMS per battery, which does have some advantages; but it is now possible to accomplish the same thing with Victron Lynx BMSs for up to 5 batteries. If you parallel the Lynx BMSs and connect just one battery to each BMS, then you’ve accomplished one BMS per battery using this external BMS — albeit at an additional expense of about $1000 per battery after the first.
I agree about Lithionics and so do several of my sources who really understand this stuff at a very deep level. That said, these days I think I would lean toward Victron or Mastervolt.
George L
August 2, 2025 2:57 pm
Thanks John for writing this and kicking off a great thread!
Als thanks for the authors of all the great comments.
Just one minor addition – this was discussed by some of the very competent participants of the two-day on-site Victron training we had the chance to attend.
Victron certifies a number of much cheaper Lithium batteries to be compatible and tested with their kit. I need to find the link for details.
Said installers are mostly doing quite large house and business installs, both for autonomy or for backing up the ever worse grid power and where the battery capacity is quite huge for boater standards – 100 kWh and up (5 time the current M&R setup. At that size, battery cost bites. This would be relevant for electric propulsion, and if I really needed that much, I’d look into a proven and approved alternative.
For typical sailboat use, 10 kWh is likely already at the upper end, expecially when a genset is present, hence less battery is feasible. In that latter case, and that’s our choice, I would and I will go with the integrated systems. However much spending the few extra grand hurts, it isn’t worth it.
Good point, and I think it’s way cool that Victron does this instead of being aggressively proprietary as many companies are.
And in fact my daughter and son in law have an RV with a Victron Lynx system, but batteries from another vendor that seems to work fine.
That said, I’m not sure I’m comfortable with the words “Victron certifies” which would imply that Victron guarantees that everything will work fine and safely.
What they say is: “Specific information about batteries that are known to have been tested:”
That implies to me that someone, somewhere, probably the battery manufacturer in question, claims to have tested their batteries with some Victron gear, a very different and much less reassuring situation.
And one thing I think we can be pretty sure of is that if we connect a non-Victron battery via CanBuss to the Victron system and something does not work, Victron are going to tell us to go talk to the battery vendor, not take ownership of fixing the problem.
Given this, if it were me, I would go with, and heartily agree with, your recommendation to use Victron batteries to save the ambiguity about responsibility for problems.
Dieter Kowalewski
August 3, 2025 8:06 pm
With all the new technology and the hype surrounding it, everyone should really ask themselves if it’s truly necessary to spend a lot of money on an upgrade. If weight and space aren’t an issue, as with a boat the size of an M&R 56, does it really make sense to switch to lithium? My old gel (yes, gel, not AGM!) batteries provided all the power I needed for 13 years without any problems. Two years ago, I installed new gel batteries again, and I’ll probably be able to live worry-free on the boat for the next 10 years with them.
On the other hand, I’ve heard about a lot of problems with lithium batteries; many have experienced a blackout. In one case with a predominantly Victron system, nothing worked after an update, and Victron service couldn’t help either. Only a Victron technician in England was able to resolve the problem. This, in turn, confirms the entire article: if you go with lithium, then it should be a truly complete, integrated system from one provider.
You make a very good point that should never be forgotten by anyone considering a change to lithium. The bottom line is that the complexity of lithium means it will always be more vulnerable to problems like your example. The great thing about lead acid is that there is no software in the system that can cause the lights to go out, and we should never forget that. Also interesting about your decision to stick with gel. At one point I was a bit down on gel because generally they can’t be equalized, but I think I was probably wrong: https://www.morganscloud.com/jhhtips/gel-batteries-a-winner/
Drew Frye
August 6, 2025 10:32 am
I read an article by Ron Collins (Mainesail) where he expressed that lithium was not ready for DIYs, and he’s a big lithium fan. The complexities are considerable. This small group understand them, but face it, you guys are into this. Most sailors just want the lights to come on. He is not the only one to have expressed this. (“Not ready for prime time.”)
I did something very simple for my F-24. Most of the complexities discussed here do not exist. I charge only with solar and I really don’t care about dark ship risk, since there is nothing electrical I really need. In the case of hauling anchor in front of an approaching storm (I had a windlass failure once on my PDQ), I would not spend more than 5 minutes troubleshooting before I would recover the anchor manually, which I know will work in the time available. Troubleshooting is never sure and you are burning time.
After reading all of this I get the feeling that for most people, unless lithium was designed into the boat from the ground up, they should expect a major ground-up renovation and need a real pro, not just the guy the marina recommends, and identifying that guy could be challenging. And even then, they must be ready to really trouble shoot the system in remote locations. I’m pretty sure I can jury rig a LA system in any corner of the world. LiFePO4, my options will be far less. electric cars had some serious teething pains, and sounds to me like we are still in that phase. There are mature systems, but we’re still not out of the teething pain phase regarding aftermarket installation. Maybe we never will be. Some projects are never average DIY and some projects are troublesome even with pros.
Interesting. I was about ready to install lithium on my cat for better AC away from the dock, but I sold the boat. Knowing what I know now, I think I might keep two LA batteries and install stitches as required to isolate the lithium system in the event of failure. I could get by cruising with a pair of LA batteries, rather than just one set up as a dump load. It would also solve my winter problem.I don’t know.
Hi Drew,
I think you’re right, as you might already have guessed. I still think any reasonably adept person should be able to spec and build a good Victron system. It’s certainly not just plug and play, but the extras are simple enough to understand for anyone able to focus a bit, and good advice is plentiful online, especially on the Victron forums.
However, what I worry about, which is what Rod Collins mentions too, is that so many users try this as their first DIY project, or are simply not able to focus anywhere near enough. Both are OK if fixing a wheelbarrow, but not when working with very expensive components that contain huge amounts of energy. Lead acid batteries can also release massive lightening bolts or even explode, but they and all around them are closer to the wheel barrow in complexity.
So I think lithium is absolutely ready for DIY, on the one strict condition that the DIYer is the right type of nerd. Lithium is NOT ready for the average fixer who tries to save some money. The majority of those will certainly end up loosing money, if compared to an installation designed and assembled by someone actually competent.
As mentioned earlier, finding such a person is NOT an easy task these days. I know this, since I work with it and know the companies constantly look for suitable people. They barely ever find anyone. Which is why they still ask me for advice or help, even though I’m not competent enough to do pro work and have nicer things to fill my days.
Lithium is flooding into the boating market, but not in a good way, as we’ve seen many times before with other new tech. I think it won’t completely ruin the lithium idea, since there is also so much good, but there’s certainly a lot of sand in the machinery.
All makes sense to me. Your point that people who really don’t have the base skills, including so called pros, should not be taking this on, but are anyway, particularly resonated for me. For example, I only know of one pro in all of Nova Scotia who I would trust to install a lithium system. This will sound harsh, but I think the biggest problem now with lithium is when people mix it with the Dunning Kruger effect and that probably the pros are the most guilty here since many (hopefully most) DIY owners will have a clearer idea of what they don’t know.
Drew Frye
August 6, 2025 10:37 am
The insurance thing puzzles me. Boat fires related to shore power, bilge pumps, missing fuses, and just plain dumb stuff happen every day. I’ve got to believe LiFePO4 fires are a rounding error. The few examples I’ve seen did not relate dirrectly to the battery type (chafed cable or similar) and the batteries did not significantly add to the fire. I can understand a ban on other lithium chemistries.
Is it the mysterious “department in charge of NO?”
Hi Drew,
I think the insurance companies are just afraid of the unknown unknown and prefer to say no too early. They probably don’t really understand the tech and react to the “lithium” key word. There has also been people putting used non LFP car batteries into boats, which is a very bad idea and has ended bad too sometimes.
Still, the vast majority of battery related fires on boats reportedly originate in phones and similar, which all have the less safe chemistries. They have way smaller batteries, which means less energy, but still plenty (!) to destroy any cruising boat.
I do wonder why they don’t dare to mention that little problem.
I’ll fully agree with you, John, about the advantages of mature, single-vendor, fully-integrated systems often justifying their additional expense. That opinion comes from decades of experience as a software engineer. I’m also now an Apple guy, not only for employer-supplied hardware, but also for my personal needs. That approach affords me more time to concentrate on things I should instead of on endless technical distractions.
I’m not entirely with you on the maturity of the batteries themselves, however. There are still significant changes in battery technology that are in process, driven largely by the electric vehicle market. That means that enticing new batteries will continue to come out for some time, but they often won’t be able to be integrated immediately into single-vendor systems without compromises or giving up some of the advantages of those fully-integrated systems. Right now, I am thinking about the enticement of lighter, safer solid state lithium batteries like those from Solid State Marine, but I am confident that there will be more examples in the future as battery technology continues to evolve.
One last note: There’s another reason to wait a bit on the Victron NG batteries. The current Victron data sheet shows that the UL and IEC safety certifications are still pending on half of the new battery models, so it may make sense to boaters and insurers to wait until those are completed.
Hi Mark,
I think the difference here is one of semantics. I don’t equate maturity with the end of innovation. For example I have considered the Apple system mature for at least 10 years even though they made the huge change to their own chips about five years ago. To me what makes Apple mature is that they were able to make that change smoothly.
As to UL approval, sure, that’s always the case. Getting all these approvals is time consuming and expensive and must be done for every new model but I don’t think it’s significant to the question of maturity. Also I think it’s way past time that ABYC recognized European standards. We have some of the same proprietary standards issues in Canada, for example for MOB beacons, and it’s just silly and causes unnecessary friction and expense.
Anyway, are you sure ABYC requires UL on the batteries? I have not checked that. And if they do let’s not forget there is a whole world out there that includes the majority of AAC readers that uses other standards, many of them actual standards, (rather than industry guide lines) with the weight of law behind them.
ABYC standard E-13 for lithium batteries requires lithium batteries or cells to meet the testing requirements of at least one of the following standards: IEC 62133, IEC 62619, IEC 62620, SAE J2929, UL1642, UL1973, or UL 2054.
Note the expression “meet the testing requirements of,” which ABYC uses in many standards. A manufacturer could satisfy the ABYC requirement by paying an independent lab to test a product according to UL protocols without actually going through the expensive and onerous process of acquiring and maintaining UL listing.
ABYC E-13 was under review this year. The updated standard should be out this month. It will be interesting to see what has changed.
Hi Earl,
Great news.
Thanks, you saved me wading through E10 and 13. I must have read each at least four times over the years, but although my memory is still good at 74, it doesn’t last as long.
And yes, I’m looking forward to the new version of E13, particularly since I was rather disappointed with the first go around.
First, I didn’t mention anything about ABYC requirements. While ABYC E-13 does reference the UL and IEC standards that Victron lists as certification pending for half of the NG batteries, I’m simply saying that waiting for the products to complete those safety certifications may make sense to provide better defense against a claim denial on the grounds that installed batteries were unsafe. It’s just more weight behind your already present recommendations to delay using an NG system on other grounds.
Second, IEC 62619 is a harmonized European standard (an EN-IEC standard). Curiously, Victron’s CE Mark certification lists EN IEC 62619:2022 even though the product data sheet shows IEC 62619 as pending for half the products listed in the CE certificate. I don’t know what the full story is on that, but again, seeking clarity on such safety certifications can be a legitimate additional reason to delay.
On the battery maturity issue, I think you’ve missed the point a bit. Yes, an integrated system developer will typically further integrate their own innovations in a timely fashion (as Apple did with their own chips and Victron did with their own battery management technology); but with marine batteries we should still be expecting significant and even rapid technological development from other companies than Victron or Mastervolt. Those third-party products often won’t be integrated in a timely fashion (if at all) into the fully-integrated ecosystems. In a regime of rapid, ongoing technological development, going with a fully-integrated vendor’s system often will preclude using third-party products that incorporate significant technological and functional advances.
Being a step or two behind the bleeding edge doesn’t mean that the integrated product lines are useless or don’t provide value and quality service. But it is just another compromise to be aware of when choosing to go with an end-to-end, integrated-system vendor.
Hi Mark,
I agree with all that, but don’t understand why any of it caused you to suggest that I was wrong that lithium was mature. Any mature product can be disrupted by an innovation. For example lead acid batteries are mature technology but are rapidly getting obsoleted by lithium (for many uses).
What’s next after lithium? Beats heck out of me, but there will be something and if I had to guess it will be something none of us have thought about…but I could be wrong. So sure, we could buy a full Victron NG system today and have it totally obsoleted by something new next year, but that does not alter that the Victron system was mature and a good buy at the time, and perhaps for many years afterward, just as lead acid was the best bet for most of us for at least a decade after lithium boat batteries.
I would also suggest (again) that you couch your comments more carefully. Starting by telling me I missed the point, was unfortunate. Missed my point would have been better and I find it better still to start with “perhaps I was not clear”. That may sound pedantic but it’s little details like that the contribute to the collegial atmosphere at AAC—I have taken years to learn this, and still make mistakes.
Perhaps the issue is that “lithium battery” isn’t precise, nor is it limited to liquid electrolyte LiFePO4 batteries. What’s next after those LiFePO4 batteries is already pretty clear: the solid state lithium batteries that are becoming well-established in applications like electric vehicles and drones, and are starting to emerge as marine batteries. It’s analogous to the difference between flooded lead-acid and AGM batteries, but the solid state lithium chemistries are and will be a little further apart from current LiFePO4 batteries than the difference in battery chemistry between flooded and AGM lead acid batteries. To push the analogy a bit further, Victron’s “Next Generation” lithium batteries are like coming out with a new flooded lead-acid battery when AGM was poised to take over the market. They’ll still work, but Victron’s NG batteries are not the new hotness in lithium batteries, and do not feature the significantly greater charge and discharge rates as well as improved safety at half the weight that solid state lithium does. With Victron’s NG batteries only newly on the market, it is likely to be years before Victron offers fully-integrated solid state lithium batteries.
Hi John
On many occasions you put insurability and compliance with some standards on the top of the priority list. At the same time neither one of them is in itselve equivalent to good seamanship.
The in surability has actually nothing to do with seamanship, and standards, well, they must be un derstood and checked too. Being insured and fully complaint will not help al sea.
Hi Ignat,
Good point, it would have been better to make seamanlike a separate bullet at the top. That said, I do write further up the Tip:
The Mastervolt Lithium batteries have been around for over a decade and have redundant internal BMS systems…they have stood the test of time. I would give any new systems 3-5 years before using.
He Peter,
I agree on Mastevolt and would argue that they were the first to reach true maturity of a lithium battery system.
And normally I’m totally with you on waiting on new stuff: https://www.morganscloud.com/2013/10/25/want-to-get-out-cruising-dont-be-a-pioneer/
However in the case of Victron my thinking is that this is simply an evolution of their product line, so six months to a year delay works…I’m also a total Victron fan boy because there stuff has just worked for me.
Also, as a general rule I prefer external BMSs, so I really like that with Victron NT we can have that with automatic fail safe backup. That said, I can also see the benefits of the Mastervolt approach which is, I think, better than most internal BMSs.
Hi John,
The M&R 56 now has an integrated Victron system with DC/DC to charge start battery and high output alternator for house. It’s been amazing.
Hi Whitall,
Great to hear, and that it’s working well. What bank size did you go with and did you add any solar? If I had kept the boat I was going to add two flexible panels to the ridged Bimini.
I added some loads: washer/dryer, watermaker, Starlink, and wanted optionality for electric cooking. House bank is 400AH @ 48v. Alternator is now 130A @ 48v with Wakespeed regulator.
All DC appliances remain at 12v (except fuel pump!) but with dual pole breakers. Had to deviate from Victron for the 48/12 converters as only Mastervolt had a suitable offering.
Start battery is the same AGM that doubles as the 12v service battery to absorb inductive loads and remains in float from the Mastervolt converter/chargers. They are bi-directional so accommodate the solar controllers to boost charge the house bank.
Added two 160W rigid panels on the bimini that leaves a foot path down the middle.
As an aside added a stray current continuous monitor along with your VDO stray current meter, but that is another topic for another day.
Hi Whitall,
Wow that was quite a rewire job! I thought about duel breakers for years but always chickened out. What stray current monitor did you install? I have never heard of a continues one.
At the risk of comment thread drift: https://selcousa.com/product/kpm169/
Monitors resistance between hull and DC neg. Alarm goes to N2K network. Too bad it’s so ugly.
Great article with useful logic and advice presented here. Is the system flow diagram available as a PDF (as it would be a great reference)?
I recently got a copy of the electrical schematic from Quorning Boats for a new Dragonfly 32 which had a Victron lithium battery system and the design elements are very similar if not identical to what is presented here.
Bob
Coincendantally enough I bookmarked that exact schematic just last Friday.They have a LOT of schematics available depending on the application. I believe this one is the “Genless monohull…”
https://www.victronenergy.com/communication-centres/cerbo-gx#downloads-system-schematics
Hi Ben,
Thanks, you got it.
Thanks Ben.
Low temperature charging put me off lithium for a long time. But I just switched, mostly because my LA gave out due to age. And boy was the installation weight better! Only 6 months in, but so far so good.
Victron mentions a low temperature cut-off (sold separately).I did not see a provision for heating the batteries, as is done on Teslas. Granted, most sailors don’t cruise below freezing (but I suspect you may), but many keep boats in the water when battery temperatures could go below freezing, even with the buffering effect of seawater.
For me, a low temperature charging cut off was enough, since when it’s that cold I either stay ashore or day sail and forgo charging and power use both.
Thoughts? I would think a high latitude sailor would need a robust solution.
Hi Drew,
Many integrated LFP batteries have a heating element inside. If temps are too low, there’s apparently a relay that disconnects from charging and uses the incoming power from the charger to warm up the cells. When warm enough, the heating stops and the power goes into the cells. I assume this explanation is incomplete, as I have no personal experience with it, but I imagine it should be possible to DIY something similar too. Some resistive heating plates, a temp sensor and a relay…? I’ve not looked into it, but had it in the back of my mind for a while.
The problem with that system (I explored it) is that you must have considerable charging amps available, probably more than you have away from the dock.
If you are charging with solar it is low risk, because you are probably charging at a very low rate in the winter. My understanding is that LiFePO4 is not at significant risk at C<0.05 (about 20 hours to full charge). My solar charging C = 0.03 in full summer sun, but more realistically C<0.01 with the amps I actually see in the winter.
I guess I will report back after a few winters! I do go out when it is well below freezing. The greater concern is actually at the dock, because I do not plug in.
—
I do wonder if we will start hearing of problems from people who believe the lithium “drop-in” claims without reading the small print. I have heard (first hand reports of fellow F-boat owners) of problems with electronics getting fried by BMS disconnects. Basically, charging from a dumb source (outboard) and letting the battery regulate. That is not at ALL what you are discussing. In fact, I do not use my outboard as a charging source, in part because I don’t need to, in part because for a day sailor and occasional weekender the time is too short to contribute anything meaningful, and because I know it’s a dumb charging source.
Hi Drew.
Interestingly enough I never had cold issues with batteries and would probably would have been fine without heaters in lithium batteries. I never wintered over (on my own boat) except in Arctic Norway where we were plugged in and had plenty of heat. And when cruising in the summers I suspect the lithium batteries would have had a higher coldest temperature tolerance (+5 charging) than me and my crew! That said, I might have upped the insulation on the battery compartment. Seems to me that your solution should work since you could always sail and then return to the marina, warm the boat, and charge.
Hi John,
I agree that Victron has reached maturity with their battery systems, and have proven that over more than a decade. I don’t know Mastervolt and Lithionics as well, but they’ve also proven knowledge for a long time.
Still, I don’t really feel that the lithium battery market is anywhere close to maturity. If consumers for some reason don’t pick the right brand(s), they’re pretty much in the same situation as several years ago. The product suppliers all claim great things, which usually contain several flat out lies.
I think there are too many traps and too many predators operating in the market, with not enough resistance. They exploit the opportunity given by the sticker shock from a full Victron system.
I think there’s still a place for the nerdy DIYer, who can now reliably get good cells and other components for a self build, or pick with skill among more integrated solutions with cheaper suppliers. If you’re not a nerd and can’t afford Victron, the “Rolls Royce”, it’s hard to avoid poor solutions.
Conclusion: The technology has reached maturity, and it’s available, but I think the market in general is still in a “wild west” state. The nerds are the gunslingers who can survive in the lawless environment. 🙂 The normal cruiser is still mostly being milked unfairly.
Hi Stein,
I agree. I guess we could say “Lithium Batteries are Mature” but the market is not. In my defence I do qualify maturity with a blue box pointing out that the installer (pro or owner) must know what they are doing.
Agreed. There are players in this market who have reached maturity. If you go to Victron, Mastervolt, or Lithionics, buy their stuff, and follow their directions, it will work as promised.
The market as a whole still has a lot of immature players.
This is very much akin to the state of other industries at this stage of development. The car industry has many mature players selling quality products with long-term support, but that didn’t stop people from being burned by buying a Fisker Ocean and then seeing the company and the parts supply chain disapper overnight.
Caveat emptor.
Comments on other forums suggest that insurance companies (UK based) are not insuring DIY installation of lithium based systems unless signed off by a competent person and in some cases will only accept professional installation. I use the term “lithium” deliberately as there is no separation of battery types by insurance companies, as mentioned on the forum i.e. all lithium based batteries are lumped together. It is also suggested that there is now a reluctance by competent persons to sign off DIY with previous approvers now refusing. The forum in question is YBW/Practical Boat Owners Reader to Reader/Insurance for an Electric Yacht Conversion, dated Wednesday 30 July 2025. At least one contributor owns a coded boat (coded for commercial use) and as such will now not convert to LiFePO4 as it becomes cost prohibitive.
Insurance issue also reported on another thread https://forums.ybw.com/threads/diy-lifepo4-installation-dont-do-what-i-did-maybe.616839/.
Hi Alastair,
I’m sorry to hear that, although it does not come as a surprise. I took a brief look at the thread and it’s worth noting that this was a home brewed battery from cells and a BMS, not a full system that has passed certifications like the Victron. Given that, I don’t really blame the insurance company. Sure, a safe battery could be built by an amateur, but how on earth would any insurance company assure themselves of that?
Very interesting read.
I’d like to share my experience on Victron NG package.
I switched from 4 AMG 200Ah Victron batteries to 2 200Ah LFP NG victron batteries just 3 weeks ago.
I asked professionals to do the upgrade as I had other things to do.
I enede up with:
2 ng LFP batteries
1 bus
1 bms
1 distributor
2 Orion DC2DC chargers (to limit and adjust the alternator output)
1 battery protect box
Today my son did started to lower the anchor and in an instant the whole boat lost 12V power. I lost all 12V powered devices including windlass and VHF. I guess he pressed to many buttons.
This happened few hours before the predicted major storm in Croatia.
I was luckily able to fix the problem within one hour, with a hanging hook on 20m of released chain floating in the harbour.
The problem was the battery protect box which failed. I bypassed it and everything started to work.
Additionally:
My personal conclusion:
I believe I made a mistake by upgrading to NG everything integrated super duper system from Victron. I should have taken the time to take a closer look before the installation. Its functionality is a downgrade to what I had before (my alternator now charges the batteries much slower), I have a boat full of new shiny boxes and new cables and it cost my crazy amount of money not for batteries only but for all other super integrated boxes I had to buy.to get 2 batteries installed. If I could I would go back to my good olg AGMs and then do a proper simple upgrade to LFP nonintegrated much more reliable and cheaper system that would actually work.
I would advise people to take a good look at the LFP system before they upgrade and I would actually suggest to look away from Victron as sad as that sounds.
Hi Roman,
I’m sorry for your bad experience and hope you can figure out a way to improve the situation. I know far too little about your problem to be able to give any meaningful advice, of course. Still, if I were to speculate, I’d point to the people doing the installation.
I have many decades of experience with boating. I’ve also worked much in the business and now I’m a pro skipper and do some tech on electric canal boats. My qualifications: I can figure out things and I’m not too clumsy… Is that enough? Well… There are no real rules or limitations. I’ve seen so much plain stupidity I’ve stopped being shocked.
No “pro” boat tech is allowed to touch my boat. There are some amazingly good boat tech people, but they are about as easy to find as unicorns. My respect for leisure boat professionals in general is on par with lawyers and used car sales persons.
The people installing the new shiny lithium tech, no matter what brand they push, are most likely of the above described quality. They are most likely totally incompetent, and don’t even know themselves how bad they are. Google “Dunning-Kruger”. No matter how good components they use, they will sabotage the system as a whole, since they have no idea how it works.
Victron make products that are simple to install, if compared to the competition, but that doesn’t mean it’s actually simple and doesn’t need proper knowledge. It can’t be “winged”. The correct components must be chosen, they must be connected right and be programmed right. I think you have become another victim to what I described in a previous comment, the “wild west” attitudes in the lithium for boats market. We need good products AND good people.
Hi Roman,
Sorry to hear that.
First off, I totally agree that any upgrade from lead acid has the potential to have teething problems. That’s simply a given because all lithium systems are so much more complex than lead acid. In fact I repeatedly warn of this in our online book: https://www.morganscloud.com/2023/01/10/a-simple-way-to-decide-between-lithium-or-lead-batteries-for-a-cruising-boat/
I also recommend a serial backup for all lithium systems, or at least ones that don’t have multi bank backup: https://www.morganscloud.com/2022/07/03/building-a-seamanlike-lithium-battery-system/
The bottom line is that lithium systems have more to go wrong, and therefor a failure is more likely than with lead acid, so a backup system is pretty much required to be seamanlike.
As to your specific issues:
The good news: I think you have most of what you need to make this system reliable and all the information you need is in our online book:https://www.morganscloud.com/category/electrical/online-book-electrical-systems/
Thank you Stein and John.
I’m sorry for a bit bitter context of my post. I posted it one hour after I solved the issue and was in gentle Victron “killing mode”.
I agree with what both of you said above.
I will certainly be much more careful and hands on when I upgrade my other boat.
Upgraded alternator with capable regulator would be my choice. It certainly is the way to go. And it would actually be cheaper, more stable and better overall.
Some kind of smaller backup 12v system would be very reasonable at least for critical systems like VHF (so I could call for help).
The thing that bothers me is the failure of Battery protect module. It crashed. The simplest part of the installation was the cause for the problems. In my opinion it is also overkill for my installation and will not use it in future.
Victron should make sure that my scenario can not happen.
I can imagine novice owners of new boats with Victron NG by the book installation ending up in my situation. They would be very lucky not to cause damage to their and other boat, if not altogether beaching it in the middle of the storm.
Best regards,
Roman
Hi Roman,
I agree blackouts are dangerous, but I really can’t see how Victron could build a system that make them impossible. After all blackouts ocure on lead acid boats too, but less often because lead acid is so much simpler with almost nothing to go wrong between the battery and the load. But that’s simply not possible with Lithium because it’s intrinsically fragile and therefore requires all kinds of complex stuff to protect the cells inserted between the load and the battery. Bottom line, I just can’t think of any way to have a totally blackout proof lithium system other than the serial backup we suggest. The good news is that’s pretty easy and cheap to do, and can power way more than just a VHF, or at least have a switch to move other vital loads in seconds. All detailed here: https://www.morganscloud.com/2022/07/03/building-a-seamanlike-lithium-battery-system/
Hi again Roman,
I got interested in this and read the manual for the battery protect. It may be that it failed, but it’s also a very real possibility that the tech who installed the system did not program it properly in lithium mode. I’m guessing this because it cut out when your son activated the windlass which would cause a sudden drop in voltage.
In lithium mode the battery protect is actually controlled by the BMS but if the tech did not run that control lines from the lynx AND use bluetooth to change the battery protect into lithium mode that’s exactly what would happen, particularly if any wiring was undersized or there was a bad contact anywhere.
Worth checking.
Hi John,
I think you’re spot on. I was also wondering if the Victron Battery Protect is a good choice for this setup. It’s a diode based item, meant for more “stupid” systems that might need what the name describes. In a battery system that has a high tech BMS, that seems like strange choice, but I haven’t looked properly at it, so I might be wrong.
You do want some means in a Victron Lynx BMS system to cut off battery loads while chargers remain connected. Otherwise the contactor in the BMS may open, disconnecting everything.
Hi Mark,
True, and that would leave the charging sources connected so we could switch one on immediately to solve the problem, without screwing around to get the Lynx reset.
Hi Stein,
I too have wondered about the reason for the Battery Protector in a system with a Lynx BMS. That said Victron clearly shows them in their recommended layout so I guess they must think it necessary. Some time, probably this winter, I need to take a deep dive into the manuals to understand the issues and tradeoffs better.
It was my thought as well that the Battery Protect could be exposing a problem with excessive voltage drop under load rather than itself being the cause of the problem. A dumber electrical system may continue to work while the problem remains hidden, but that isn’t the same thing as there being no problem.
Hello John, I am interested in the Victron lithium battery lay out.
Unfortunately the resolution of the drawing is insufficient to let me read the text when the image is enlarged.
Would it be possible to send me a link to the original file?
Regards Steve Ferguson. Tasmania, Australia.
Loving the AAC website.
From Victron -> Products -> Batteries -> Lithium NG -> System Schematics: https://www.victronenergy.com/upload/documents/Genless-monohull-with-Victron-MultiPlus-Lynx-Smart-BMS-NG-600Ah-NG-Li-HP-Alternator-Wakespeed-WS500-Pro-regulator.pdf
While predating Lithium NG, for anyone looking to understand the big picture of electrical systems, I would recommend the Marine System Booklet. It took me a good while to independently end up exactly with the system labeled “An inverter/charger system being monitored via Bluetooth and the VictronConnect app, via the VE.Bus Smart dongle.”
I fully agree with the article. Tone of voice -wise I find John should perhaps be more honest about his inner geek. Us geeks often choose Apple even if we would know how to configure and build a PC.
Here you go: https://www.victronenergy.com/batteries/lithium-ng-batteries#downloads-system-schematics
My issue with the Victron universe is that they typically only have one BMS controlling the paralleled batteries. Granted, the Lynx uses a (supposedly superior) mechanical contactor, but doesn’t this disconnect both charge AND load if there’s a fault condition detected? That’s why I’m looking hard at the Epoch Elite batteries, each with a very well designed and integrated BMS. As for the MOSFET v. Contactor debate, mechanical contactors are not impervious to failure. Well-built MOSFETs with the proper amperage rating seem reliable enough, especially in a system with 2 or 3 BMS’s in parallel. I’m sure there are bad MOSFETs, and good, the same with contactors.
Brian on Helacious, currently West coast of Iceland
Hi Brian,
I’m no electrical engineer, but AIFK the problem with diodes isn’t primarily reliability, it’s their failure modality. I’ll probably use some non pro terminology, but I hope it makes sense:
They fail to closed, meaning they let the power flow freely. That can be pretty catastrophic…
Relays for this type of use are “normally open” type, which need a small control current to move from open to closed. If anything goes wrong, no matter what, it fails to open, breaking the connection.
To me, this seems like a must have property, making diodes a dealbreaker in this function. On top of this core flaw, diodes have a strict limit on current, which will severely limit the capacity the cells have, and diodes cause Voltage drop etc. So they eat power. To me it makes sense that the high end companies only use relays for this.
I assume more educated people will fill in here.
Hi Brian,
I hear you on this, but aside from the excellent point that Stein makes there is also a far from obvious architectural difference between the two options: A battery like the Epoch needs two busses because it has no way to control all the charging sources so it has no alternative but to disconnect the charge buss from the cells and by having two busses it can leave the loads supplied. All good, but the problem is that any time we cut off a flowing DC current in that way we risk a voltage spike. We all think of this in connection with alternators, but it’s true, albeit to a lesser extent, of all charging sources, and spikes stress electronics over time, so this is not best practice, although it does work.
On the other hand in the Victron system the BMS directly controls all charging sources so rather than cutting them off, it just tells them to shut down elegantly with the batteries still connected. Therefore it does not need two busses because it’s not going to disconnect the batteries. The contactor is only there as a last line of defence in case something goes wrong and to satisfy regulation.
A good way to think of this is that the contactor is like a circuit breaker that will only activate when something has gone really bad, but the MOSFETS are part of general operation.
(To be fair, I seem to remember, (might be thinking of another product) that some of the Epochs also have contactors built in and also some Epochs can work with the Victron system to control charging sources. That said, by so doing we lose the benefits of buying from all one vendor and open ourselves to the horrors of parsing the finger pointing when something goes wrong. And as a guy who founded and ran a computer systems integrator building complete business computers with hardware and software from multiple vendors, trust me, it’s no fun! But at least I got paid well for it.)
The Epoch Elite can use Cerbo’s DVCC feature to control certain charging devices like the Blue Solar and the Multiplus. But not the Skylaa charger, and not the Wakespeed, apparently. C’mon, Epoch.
The Victron Smart Battery Protect devices that Victron shows in their diagrams are MOSFET devices. Their Lynx BMS uses these SPBs to control the day-to-day ATC (allow to charge ) or ATD (discharge) functions. The contactor in the Lynx is there as a failsafe backup. Wouldn’t the primary class T fuse protect against a catastrophic over-discharge situation? What is needed is a contactor to monitor and disconnect charging should the BMS’s MOSFETs (which are not actually diodes but sometimes behave like diodes) fail and a over-voltage (above 14.6vdc) situation occurs. What is that device? Basically we need a BMS for our built-in BMS’s! This is why I have avoided lithium for so long…
Hi Brian,
Thanks for the fill in the Elite, it’s just these kinds of complications that lead me to sticking with one vendor.
No a fuse won’t protect against over charge since a lithium battery will be trashed way before the fuse blows.
And yes, I understand what the Smart Protect do, although I would be the first to admit that without a really long dive into all the manuals, some of the details may escape me.
As to other things that the system may require or not, I guess I pretty much trust Victron to be getting these sample layouts right, so I’m not expending any brain sweat (or time when I could be sailing) on trying to second guess them.
And yes, I agree, lithium is complicated, and always will be because these batteries are fundamentaly fragile and therefore need a lot of stuff around them. Definitely not for everyone and no shame in saying “not for me”. Still, for those who want to take it on, I think today we can be pretty comfortable with a Victron or Mastervolt system, at least as long as we know what we are doing and don’t deviate from the recommended set ups.
Yes, batteries with integrated BMSs have a BMS per battery, which does have some advantages; but it is now possible to accomplish the same thing with Victron Lynx BMSs for up to 5 batteries. If you parallel the Lynx BMSs and connect just one battery to each BMS, then you’ve accomplished one BMS per battery using this external BMS — albeit at an additional expense of about $1000 per battery after the first.
Of course if money were no object, Lithionics has a very fine solution. I’m searching for “value engineeering”.
Hi Brian,
I agree about Lithionics and so do several of my sources who really understand this stuff at a very deep level. That said, these days I think I would lean toward Victron or Mastervolt.
Thanks John for writing this and kicking off a great thread!
Als thanks for the authors of all the great comments.
Just one minor addition – this was discussed by some of the very competent participants of the two-day on-site Victron training we had the chance to attend.
Victron certifies a number of much cheaper Lithium batteries to be compatible and tested with their kit. I need to find the link for details.
Said installers are mostly doing quite large house and business installs, both for autonomy or for backing up the ever worse grid power and where the battery capacity is quite huge for boater standards – 100 kWh and up (5 time the current M&R setup. At that size, battery cost bites. This would be relevant for electric propulsion, and if I really needed that much, I’d look into a proven and approved alternative.
For typical sailboat use, 10 kWh is likely already at the upper end, expecially when a genset is present, hence less battery is feasible. In that latter case, and that’s our choice, I would and I will go with the integrated systems. However much spending the few extra grand hurts, it isn’t worth it.
Hi George,
Good point, and I think it’s way cool that Victron does this instead of being aggressively proprietary as many companies are.
And in fact my daughter and son in law have an RV with a Victron Lynx system, but batteries from another vendor that seems to work fine.
That said, I’m not sure I’m comfortable with the words “Victron certifies” which would imply that Victron guarantees that everything will work fine and safely.
If we look at their page on this: https://www.victronenergy.com/live/battery_compatibility:start
What they say is: “Specific information about batteries that are known to have been tested:”
That implies to me that someone, somewhere, probably the battery manufacturer in question, claims to have tested their batteries with some Victron gear, a very different and much less reassuring situation.
And one thing I think we can be pretty sure of is that if we connect a non-Victron battery via CanBuss to the Victron system and something does not work, Victron are going to tell us to go talk to the battery vendor, not take ownership of fixing the problem.
Given this, if it were me, I would go with, and heartily agree with, your recommendation to use Victron batteries to save the ambiguity about responsibility for problems.
With all the new technology and the hype surrounding it, everyone should really ask themselves if it’s truly necessary to spend a lot of money on an upgrade. If weight and space aren’t an issue, as with a boat the size of an M&R 56, does it really make sense to switch to lithium? My old gel (yes, gel, not AGM!) batteries provided all the power I needed for 13 years without any problems. Two years ago, I installed new gel batteries again, and I’ll probably be able to live worry-free on the boat for the next 10 years with them.
On the other hand, I’ve heard about a lot of problems with lithium batteries; many have experienced a blackout. In one case with a predominantly Victron system, nothing worked after an update, and Victron service couldn’t help either. Only a Victron technician in England was able to resolve the problem. This, in turn, confirms the entire article: if you go with lithium, then it should be a truly complete, integrated system from one provider.
Hi Dieter,
You make a very good point that should never be forgotten by anyone considering a change to lithium. The bottom line is that the complexity of lithium means it will always be more vulnerable to problems like your example. The great thing about lead acid is that there is no software in the system that can cause the lights to go out, and we should never forget that. Also interesting about your decision to stick with gel. At one point I was a bit down on gel because generally they can’t be equalized, but I think I was probably wrong: https://www.morganscloud.com/jhhtips/gel-batteries-a-winner/
I read an article by Ron Collins (Mainesail) where he expressed that lithium was not ready for DIYs, and he’s a big lithium fan. The complexities are considerable. This small group understand them, but face it, you guys are into this. Most sailors just want the lights to come on. He is not the only one to have expressed this. (“Not ready for prime time.”)
I did something very simple for my F-24. Most of the complexities discussed here do not exist. I charge only with solar and I really don’t care about dark ship risk, since there is nothing electrical I really need. In the case of hauling anchor in front of an approaching storm (I had a windlass failure once on my PDQ), I would not spend more than 5 minutes troubleshooting before I would recover the anchor manually, which I know will work in the time available. Troubleshooting is never sure and you are burning time.
After reading all of this I get the feeling that for most people, unless lithium was designed into the boat from the ground up, they should expect a major ground-up renovation and need a real pro, not just the guy the marina recommends, and identifying that guy could be challenging. And even then, they must be ready to really trouble shoot the system in remote locations. I’m pretty sure I can jury rig a LA system in any corner of the world. LiFePO4, my options will be far less. electric cars had some serious teething pains, and sounds to me like we are still in that phase. There are mature systems, but we’re still not out of the teething pain phase regarding aftermarket installation. Maybe we never will be. Some projects are never average DIY and some projects are troublesome even with pros.
Interesting. I was about ready to install lithium on my cat for better AC away from the dock, but I sold the boat. Knowing what I know now, I think I might keep two LA batteries and install stitches as required to isolate the lithium system in the event of failure. I could get by cruising with a pair of LA batteries, rather than just one set up as a dump load. It would also solve my winter problem.I don’t know.
Hi Drew,
I think you’re right, as you might already have guessed. I still think any reasonably adept person should be able to spec and build a good Victron system. It’s certainly not just plug and play, but the extras are simple enough to understand for anyone able to focus a bit, and good advice is plentiful online, especially on the Victron forums.
However, what I worry about, which is what Rod Collins mentions too, is that so many users try this as their first DIY project, or are simply not able to focus anywhere near enough. Both are OK if fixing a wheelbarrow, but not when working with very expensive components that contain huge amounts of energy. Lead acid batteries can also release massive lightening bolts or even explode, but they and all around them are closer to the wheel barrow in complexity.
So I think lithium is absolutely ready for DIY, on the one strict condition that the DIYer is the right type of nerd. Lithium is NOT ready for the average fixer who tries to save some money. The majority of those will certainly end up loosing money, if compared to an installation designed and assembled by someone actually competent.
As mentioned earlier, finding such a person is NOT an easy task these days. I know this, since I work with it and know the companies constantly look for suitable people. They barely ever find anyone. Which is why they still ask me for advice or help, even though I’m not competent enough to do pro work and have nicer things to fill my days.
Lithium is flooding into the boating market, but not in a good way, as we’ve seen many times before with other new tech. I think it won’t completely ruin the lithium idea, since there is also so much good, but there’s certainly a lot of sand in the machinery.
Hi Stein,
Good analysis, I particularly like the wheelbarrow analogy.
Hi Drew,
All makes sense to me. Your point that people who really don’t have the base skills, including so called pros, should not be taking this on, but are anyway, particularly resonated for me. For example, I only know of one pro in all of Nova Scotia who I would trust to install a lithium system. This will sound harsh, but I think the biggest problem now with lithium is when people mix it with the Dunning Kruger effect and that probably the pros are the most guilty here since many (hopefully most) DIY owners will have a clearer idea of what they don’t know.
The insurance thing puzzles me. Boat fires related to shore power, bilge pumps, missing fuses, and just plain dumb stuff happen every day. I’ve got to believe LiFePO4 fires are a rounding error. The few examples I’ve seen did not relate dirrectly to the battery type (chafed cable or similar) and the batteries did not significantly add to the fire. I can understand a ban on other lithium chemistries.
Is it the mysterious “department in charge of NO?”
Hi Drew,
I think the insurance companies are just afraid of the unknown unknown and prefer to say no too early. They probably don’t really understand the tech and react to the “lithium” key word. There has also been people putting used non LFP car batteries into boats, which is a very bad idea and has ended bad too sometimes.
Still, the vast majority of battery related fires on boats reportedly originate in phones and similar, which all have the less safe chemistries. They have way smaller batteries, which means less energy, but still plenty (!) to destroy any cruising boat.
I do wonder why they don’t dare to mention that little problem.
Hi Drew,
I agree: https://www.morganscloud.com/jhhtips/no-lithium-batteries-dont-burn-boats/