The Offshore Voyaging Reference Site

Lithium Buyer’s Guide—Budget: High End System

Options 1 to 3

So far in this series of chapters we have covered BMS requirements, balancing and monitoring, choosing voltage and peak current (amps), and fusing, so, in conjunction with other chapters in the Online Book, we have the tech stuff done.

Phew. Just thinking about all the stuff we need to know to install a good lithium system on an offshore boat makes me tired.

Anyway, let’s dig into the actual buy:

  • Should we just pull out the credit card and get others to do the whole job, or do it ourselves?
  • And if DIY, how far should we go with that?

There are nine different configurations to consider, so I have split this into two to keep it manageable.

In this chapter let’s examine the costs of the first three, fully integrated high-end systems, primarily from one manufacturer, so we can be sure everything will communicate and all charging sources can be properly controlled by the battery BMS:

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More Articles From Online Book: Electrical Systems For Cruising Boats:

  1. Why Most New-To-Us Boat Electrical Systems Must Be Rebuilt
  2. One Simple Law That Makes Electrical Systems Easy to Understand
  3. How Batteries Charge (Multiple Charging Sources Too)
  4. 5 Safety Tips For Working on Boat DC Electrical Systems
  5. 7 Checks To Stop Our DC Electrical System From Burning Our Boat
  6. Cruising Boat Electrical System Design, Part 1—Loads and Conservation
  7. Cruising Boat Electrical System Design, Part 2—Thinking About Systems
  8. Cruising Boat Electrical System Design, Part 3—Specifying Optimal Battery Bank Size
  9. Balancing Battery Bank and Solar Array Size
  10. The Danger of Voltage Drops From High Current (Amp) Loads
  11. Should Your Boat’s DC Electrical System Be 12 or 24 Volt?—Part 1
  12. Should Your Boat’s DC Electrical System Be 12 or 24 Volt?—Part 2
  13. Battery Bank Separation and Cross-Charging Best Practices
  14. Choosing & Installing Battery Switches
  15. Cross-Bank Battery Charging—Splitters and Relays
  16. Cross-Bank Battery Charging—DC/DC Chargers
  17. 10 Tips To Install An Alternator
  18. Stupid Alternator Regulators Get Smarter…Finally
  19. WakeSpeed WS500—Best Alternator Regulator for Lead Acid¹ and Lithium Batteries
  20. Smart Chargers Are Not That Smart
  21. Replacing Diesel-Generated Electricity With Renewables, Part 1—Loads and Options
  22. Replacing Diesel-Generated Electricity With Renewables, Part 2—Case Studies
  23. Efficient Generator-Based Electrical Systems For Yachts
  24. Battery Bank Size and Generator Run Time, A Case Study
  25. A Simple Way to Decide Between Lithium or Lead-Acid Batteries for a Cruising Boat
  26. Eight Steps to Get Ready For Lithium Batteries
  27. Why Lithium Battery Load Dumps Matter
  28. 8 Tips To Prevent Lithium Battery Black Outs
  29. Building a Seamanlike Lithium Battery System
  30. Lithium Batteries Buyer’s Guide—BMS Requirements
  31. Lithium Batteries Buyer’s Guide—Balancing and Monitoring
  32. Lithium Batteries Buyer’s Guide—Current (Amps) Requirements and Optimal Voltage
  33. Lithium Battery Buyer’s Guide—Fusing
  34. Lithium Buyer’s Guide—Budget: High End System
  35. 11 Steps To Better Lead Acid Battery Life
  36. How Hard Can We Charge Our Lead-Acid Batteries?
  37. How Lead Acid Batteries Get Wrecked and What To Do About It
  38. Equalizing Batteries, The Reality
  39. Renewable Power
  40. Wind Generators
  41. Solar Power
  42. Watt & Sea Hydrogenerator Buyer’s Guide—Cost Performance
  43. Battery Monitors, Part 1—Which Type Is Right For You?
  44. Battery Monitors, Part 2—Recommended Unit
  45. Battery Monitors, Part 3—Calibration and Use
  46. Battery Containment—Part 1
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Matt Marsh

Key points I’d like to emphasize once again here:

  • For battery packs of the size we’re considering here – less than about 10 kWh –the cost of the actual LFP cells is small compared to the total cost of the project. Basing your go / no-go decision on headline pricing for the cells themselves is foolish to the point of absurdity, and compromising on quality or performance to save a few dollars there is a fool’s errand.
  • Lithium systems can be very reliable, safe, and long-lived if engineered correctly. There are a hundred ways to get them wrong. Before you start, you need to either learn all the details of how to do it right, or hire an expert to help.
  • If you are not terribly cost sensitive, there is a lot to be said for the one-stop, one-vendor approach. Remember, all equipment from all vendors works fine on its own in the lab, but what you care about is how it works all together once integrated and installed. If you mix and match, it’s all on you; the vendors will forever blame the installer and each other without ever admitting fault. If you buy the whole suite of gear from one OEM via one distributor, and use an installer trained by that OEM, you have one spot to point the finger if there’s an issue.
Mike Evans

is it necessary to replace an engine alternator used for wet cell when converting to lithium ?

Matt Marsh

Not necessarily, but you will not get the full benefits (and value for money) of your investment in lithium batteries unless you have an alternator capable of exploiting their high charge acceptance rate. There’s a lot more detail on this in the other chapters of this online book.

Steve D

Virtually every new build project I’m currently working on (I’m in Taiwan as I write this inspecting three new builds, all lithium), and have worked on in the past three years, is equipped with LFP batteries, up to 96 feet. I’ve used Lithionics, MG, MV and Victron, and by far the greatest risk, in my view, isn’t the batteries themselves. Rather, it’s the installation/wiring and specifically wiring errors and faults. These are the same wiring faults I’ve been encountering for decades, however, the difference is LFP batteries and charging stresses the electrical system in ways it’s never before been stressed. Therefore, what was a minor fault in the days of AGM, now becomes a potential fire in the LFP world. Here’s are two common examples, one, heat shrink on cable ends impinging on the contact surface, in some cases reducing it by 90%, with consequent overloading of that contact surface and heat generation. Two, ring terminals that are not installed in order of ampacity, i.e., largest to smallest, particularly in high current scenarios. This causes high current to pass through the small ring terminal, which can exceed its ampacity, which in turn causes heating, and expansion, and that cycle causes the connection to loosen, and arc, and you have a potential fire. That will result in heat generation, a lot of it and quickly. Therefore, the onus is on installers more than ever, to practice good, meticulous and ABYC compliant wiring techniques.

Stein Varjord

Hi John,

On hours needed for DIY on any stage of this, I think your hours estimates may be correct for the time it takes to do the actual job, but including the pondering about how to do it, and the buying of the right tools, the postponing due to worrying about what to do, and so on, I think the time estimate can be multiplied with a significant number. I work with this type of stuff and have the tools and much of the knowledge, but mostly others do the hands on. The hands on guys work 4 times as fast as me, at least, when looking at the whole job. Perhaps mainly because they remove the gaps of no productivity between each task.

Spending 4 times, or 20 times as long on getting something finished, means it’s really hard to justify doing it yourself. I sometimes ask people restoring boats how much money they think is the minimum they would accept per hour for the work they’re doing. If say a meagre 10 Euros/Dollars is the answer, the boat value really needs to increase by each hour spent to justify doing it ourselves. 1 000 hours is 10 000 Euros/Dollars we need to get paid in increased boat sales price. Especially high tech work, like the stuff discussed here, is perhaps not possible to justify DIYing, unless we have no other way to spend our time, making more than 10 Euros/Dollars an hour.

Interestingly, Victron Energy, MG Energy and Mastervolt are originally all from the Netherlands. The two first are still based there, but much of the actual production is in other countries, of course. I don’t know the history behind this, but MG seems very much like a smaller brother of Victron, and Victron may could perhaps be made as an improvement of the previously very closed systems of Mastervolt? Just speculations.

George L

Very, very useful information, thanks.

where you are striking a raw nerve: the individual pieces aren’t soooo expensive it by the time you add it all up, the total blows you away …
at which point you might as well buy top of the line because doing the hours and small items make the majority of the project. In a way like there is no sense buying cheap tools …

we did quite a few comparisons, and everything Mastervolt sells turned out be quite a bit more expensive, last time we tried. They claimed some superiority in the converter chargers, that I didn’t quite get.

there is also Sterling Power from the UK, who appear to have really good kit and competitively priced.

Am I correct that this is a secondary alternator and you leave the one for the engine alone?

George L

On a small system all with the same voltage, I would agree. With a 24V house system, I’d rather keep it completely separately. But I can see the 24/12 transformer as a really good compromise.

Mark Wilson

Your final number is eerily close to the cost of a newly installed engine. A big ticket item which will probably require a degree of fettling. Something that might make sense to consider on a new build.

This subject is a source of endless interest to us readers but how much it contributes to the gaiety of nations I don’t know. Is the complexity and potential for time wasting setbacks in out of the way places really going to contribute positively to the experience of voyaging ?

To me the great benefit of these kinds of articles is to make one think more deeply than normal about what really matters on a far foreign boat. “Get thee behind me sexy new kit.” Perhaps this kind of innovation is best left to those who do their sailing in the first world – nothing wrong with that.

George L

well, if you take all the plastic in a boat, the difficulty of recycling it and the fact the most boats are unused for 11 months of the year, gaiety of nations isn’t something that would come to mind in this context. any way you try to justify it, it is a luxury item and if things work out, it will help your gaiety and that of your crew but thats it.

furthermore, the cost of a raw engine compared to the overall cost, is, sadly, not very much.

is it needed? theoretically no; just as you can go hiking into the high mountains with 20 kg of kit. If that spartan style makes you, and more importantly, your spouse happy, cool. If you can still do it age-wise, also cool. i did it 20 years ago, I don’t think it would be my way of hiking any more. Hence, if not (that is after a while), then perhaps those 16K are a really good investment.

Or if it means being able to work from your boat.

and in the supposedly first (soon to be fourth world considering the actions of the political personnel) world with a plug in marine at every corner, it is much easier to go with little than in other areas without those comforts. So this kind of innovation is perhaps much more relevant anywhere but the first (soon to be fourth) world.

As an example, I had a long conversation with a fellow who spent last summer in Svalbard and was happily going through just on solar panels and a good installation. Said he didn’t start the gen set a single time and had all the power he needed (with a diesel cooker and a refleks, so less demand).

Matt Marsh

I am totally happy with the *tiny* lead-acid bank on my current sailboat. I wouldn’t even dream of converting it to lithium.

At the same time, I have a boat on the drawing board (and partly-built in the shop) that may well end up with 5 kW of solar panels and 40 kWh of lithium batteries, and no fuels, on board. (It’s spec’d for 100% solar electric propulsion.)

Horses for courses. There is no one-size-fits-all solution. The important thing is that you pick a system that fits your own needs and priorities, and then do a good workmanlike code-compliant implementation of whatever you pick.

George L

your last paragraph is spot on

Stein Varjord

Hi Matt,

And I have to mention that John has said similar things on most topics here. Lithium is just another of the innumerable questions of this kind that we have to struggle with. “It depends…”

Nathan Moore

I’ve long held the belief that if you ask a good professional a good question, the answer will invariably be “it depends.” 🙂

Colin Speedie

Spot on, Matt. There is no perfect solution, but careful installation of whatever system you run is a necessity.

Richard Horsey

Hi John

These articles are fantastic and timely. Thank you.

I’m trying to wrap my head around all of your advice so I can make some high level informed decisions. 

In my particular case I have 3 battery banks – domestic, engine & bow thruster all 12v. Main power users – fridge (12v or 24v), freezer (12v or 24v), bow thruster (12v), electric winch (12v), lofrans windlass (12v), 2 toilets. Domestic lighting can be 12v or 24v.

I have 3x 160AH AGMs for the domestic maybe nearing the end of their life (9 years old) and probably not big enough now me and my wife will move on full time. Keeping her supplied with lots of power and fresh water is priceless if we can go cruising!

Points I am pondering…
In the high end lithium article you suggest to consider 24v and have priced the lithium and AGM accordingly but this, if I have understood correctly, differs slightly to the ’12v or 24v’ articles. Here you suggest not to consider 24v if you are already set up with 12v. 

Is it seamenlike to use eg Victron Orion to power some critical stuff inc NMEA and do without a 12v battery if converting to 24v? Is an Orion as reliable as an AGM battery?

When converting to lithium you must have a lead acid bank for the critical stuff. Why not have 24v domestic and 12v critical?

Space is not an issue on my multihull, but weight is, so adding batteries in the short term would be possible. 

Therefore Im wondering if 24v domestic with 12v critical would be good decision and allow me to do this project over a period of time?

Ie 1st step would be new lithium to power the fridge, freezer, inverter and watermaker to keep my wife smiling. Leave the 12v in place and I gradually move non essential things over etc eventually removing 2x AGMs.

Any comments gratefully appreciated. 


PS I’m checking almost daily for the next lithium articles!

Kit Laughlin

Loved the article and the comments.
A note to readers who are based in Australia: a commercial operator and friend mentioned to me a couple of weeks ago that AMSA (Australian Maritime Safety Authority) will not ‘survey-certify’ any commercial vessel that has a Lithium chemistry system on board; he had installed an Li-based system on his in-survey vessel, and had his re-certification knocked back. He replaced a $13,000 system (LiFePO4) with AGM batteries, and the certification was granted immediately.
Clearly there is a lag between best-practice and what-the-certifying-body-will-accept, at least now.

Kit Laughlin

I will contact that skipper and ask if he had suggested this option (lead acid serial backup). I am guessing not as he is not a particularly ‘technical’ guy. Your approach is a genuine systems one, one that reduces risk and maximises rewards, IMHO. Excellent article, thanks.

Richard Horsey

Thanks for the response appreciated!
How would the NMEA in the high end system priced above be powered? With a DC to DC charger as the power source?

Oscar Kramer

What about lightning? My 38′ Morgan was struck and I lost all electrical and electronics, presumably from induced currents. That was $15K worth of stuff (she had lead-acid batteries). I haven’t seen any mention of potential problems to lithium-based systems, and ways to mitigate them. That’s a lot of money to fry, at best, and potentially catastrophic if a BMS fails, at worst. Lightning is a real concern to us Florida sailors.