When we bought our J/109 I installed two 125-amp hour 12-volt Victron AGM Super Cycle batteries for a total bank size of 250 amp hours.
This is a small bank, so I selected these batteries because they are advertised as being able to withstand more very deep cycles than most lead-acid batteries, which are severely degraded by cycling below 50%.
My strategy was that over say a weekend cruise, our limited solar (50 watts), and alternator charging only when entering or leaving harbour, would generally get us through without having to run the engine just to charge, or at least not for long, but result in returning to our wharf with deeply depleted batteries that we would then immediately charge on shore power.
This has worked well and is a good example of how electrical systems need to be designed for the usage profile. There is no best, just best for task1.
We are now coming to the close of our third season on these batteries so time to report and make recommendations.
Let’s cut to the chase: These batteries have exhibited a very strange and worrying charging behaviour.
That sounds like a string of unpleasant experiences — although I can’t decide whether they’d be best characterized as frustrating, disappointing, enraging, or something else in addition to bewildering. I do have questions, though. Some of the commenters in the linked discussions were guessing that one faulty battery in a paralleled set was the cause of the troubles, so I’m wondering at what points in your tale you might have measured and analyzed your two batteries separately, whether there was or is now any measurable difference between the two batteries, or whether the whole “one bad battery” theory just doesn’t ring true for you?
Hi John,
You do a valuable service to the cruising community with these reports. Compiling the occasional reported anecdotes combined with your experience with these batteries are likely to save many a skipper a world of confusion and possible danger to their boat.
For example, I believe there are many boats who are plugged into shore power for long periods: boaters who like to leave their refrigeration going or just like to be fully charged when they go aboard. My read of your report is that that habit is not wise with these Victron batteries.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Thanks for the kind words, makes diving down a rather deep, and a bit obscure, rabbit hole worth it.
Hi Mark,
I have not separated the batteries. While useful, perhaps, just not worth my time given that the evidence is pretty solid without that. We have to stop somewhere on this kind of thing, particularly since it’s not a main stream product so not of much interest to the majority of our members who pay my salary. Also see Bruce’s comment, which clinches it.
Great test and analysis! As a Victron distributor, we had a rash of overheated/melted Victron SSAGM’s, which Victron would typically replace but without any explanation even after repeated questioning. We stopped selling them, even before Victron announced that they’re discontinuing the SSAGM (in North America anyhow) once stock runs out.
Your discovery of the drop in resistance explains a lot. Great work.
When are we getting you some lithium batteries?
Hi Bruce,
Great to get your confirmation and also good to hear that the above theory fits your experience. In many ways this is a pity because there is no question that they charge a bit faster than most lead acid so if there was a decent manual and some sample charge profiles that were safe I can seem them being a useful niche product.
As to Lithium, I just don’t really need the complication and expense for my usage profile and also the J/109 class still have a ban on lithium, so I would have to take them out when I sold her, that is unless the class relents, which I think they should.
All that said, if Victron were feeling generous with an evaluation unit…
I find this particularly interesting, as I recently disposed of a pair of these very batteries after failed attempts to revive them. To be fair, these were installed in a pop-up pickup camper I purchased second-hand, and I cannot know how they were used or maintained. They were, however, less than a year old, and were connected to a ‘RedArc Manager 30’ charger/manager (with the ‘proper’ algorithm for AGM programmed) that has performed flawlessly with my temporary install of a new Odyssey AGM battery as placeholder.
Of course it is possible – likely even – that these batteries were not cycled properly, or perhaps worse, left in a partial state of charge for longer periods. The camper itself was reportedly used for only two short trips (seemingly corroborated by unused stove and other appliances, as-new appearance/smell, and manufacturer tags and stickers still in place throughout), but as we well know, even one instance of storing an AGM in PSOC can be fatal, and reportedly this camper sat for nearly a year in storage prior to my purchase.
What I find curious, however is that only one of these two batteries (installed at same time – I have records) exhibited extreme temperatures upon any attempt to charge. Measured internal resistance (pre-charging) was higher in this battery, but ultimately, neither of the two batteries could be revived.
My research at the time (absent a manual, as you state) suggested that equalization charges were discouraged (if not disallowed) by Victron. Given that I had nothing to lose (with batteries removed for safety, and otherwise destined for recycling), I thought I’d attempt an equalization using my old bench-mounted Xantrex TruCharge 20. I quickly aborted this attempt when the battery temperature reached concerning levels.
Again, I want to emphasize that the failure mode *might* be within expectations for batteries poorly used or maintained. I’m not sure, though, why only one battery of the two in this bank would fail.
What I know of a certainty is that I have owned (and continue to own) a veritable fleet of Lifeline brand AGM batteries in sailboats, tractors, stand-by generators, heavy equipment, etc., and while I hate to confess this, most have not received the kind of charging or maintenance that promotes longevity in AGM batteries (understatement). In fact, most are charged only by factory-installed alternators, ‘stupid’ charge-regulation, and left to sit for long periods with neither use or maintenance charges. Also, these are all deep-cycle Lifeline variants, but are mostly used as starting batteries. The only saving grace with most of these batteries is that they are usually be put away with a (mostly) full charge.
Of the current seven Lifelines I have in service, the youngest is six years, and the oldest nine years. None are showing any signs of slow starting or noticeable loss of capacity. I attribute their survival and longevity to the fact that I at least give each a full equalization charge – every six months if I remember, but more realistically, once annually, with the aforementioned Xantrex charger.
Aside from the Odyssey AGMs I use in vehicles (Lifelines not available in all automotive battery group sizes, or I would use them there too), I don’t want an AGM that I cannot equalize. To date, I haven’t found anything that outperforms the Lifelines. The Odysseys have been equally impressive in automotive applications, but I’ve never used them in a deep-cycle application save for a few months of temporary use in the camper.
I’ve succumbed to Lithium for the camper, and am installing (an incomprehensibly expensive) Lithionics 320AH internal BMS battery therein. I would have preferred to stick with Lifelines for all the reasons you have addressed, but at the end of the day, the camper’s slide-out battery tray/drawer would have limited me to two group 24 Lifelines, and the combination of weight and useable capacity was less than optimal for my intended use and truck weight restrictions. I decided on the Lithionics due to a perfect form factor for this application, energy density for weight, and the fact that it is the only battery (whole assembly, not just cells) that is fully UL listed (could prove important for insurance purposes – this is a stupidly expensive camper!).
Thank you, as always, for these excellent articles! I often find application beyond the marine, though that is of course the highest priority 😉
Hi Scott,
Lots of good points. I particularly agree that I would not want any lead acid battery I can’t equalize and on the good track record of Lifelines.
Go with Mastervolt Lithium Ion. They have been around forever and have redundant internal BMS
We replaced our 7 year old Lifeline AGMs with three Supercycles totaling 510 amps on our Moody 40 while in Brisbane, Australia. We had 480 watts of solar and a 110 amp alternator and a DUO-GEN wind/water generator. We used this combo for our cruise up the coast of Australia and through Indonesia, Malaysia and ultimately Thailand. During this cruise I thought that batteries were excellent. We the sold the boat in Langkawi, Malaysia.
The buyers contacted us a few months later to report that the batteries were swollen and distorted and were potentially dangerous. The marina where they were berthed at the time forced them to remove the batteries to a safe location. VIctron Australia refused to stand behind the batteries which were only about 1 year old at that point. VIctron, USA told them to send the batteries to Florida (from Malaysia!) before they would decide if there was a fault. They basically blamed the boat owners. This was a totally unacceptable response from what I had presumed was a major and reliable company. The buyers in the end got some cheap batteries that lasted for the remainder of their cruise and then changed them out with lithium. Incidentally they are now in Japan and carrying on.
Your observations appear to explain what happened in this case. While we were using the boat we had a heavy and continuous draw from fridge, freezer, autohelm etc. I would guess that that draw was sufficient to keep the batteries from overcharging. I monitored them constantly while under way and several times a day when at anchor ( I am also a little obsessive about these things). We seldom were at a dock and normally were not plugged in. The buyers were at the dock for a considerable time before starting their cruise around Malaysia and were docked when they realized they had a problem. I don’t know but assume that they were plugged in and using the on board inverter/charger.
Victrons response, or lack thereof, to this has made me very wary of their products. What else have they got wrong and won’t admit to?
Incidentally we have Rolls AGM batteries in our new to us CS30 and they seem to be good.
Hi Edward,
I think you are right. Guys like you an I who are, as you say, a tad obsessive, get away with these batteries, but as soon as they pass on to someone who is even slightly hands off things go sideways.
I’m sad to hear that Victron did not behave well on this.
Interesting reading this was we are experiencing some abnormalities with the same batteries. I installed a 1000 Ah bank roughly 2.5 years ago as part of an electrical system upgrade along with all Victron inverters, chargers, lynx distribution, cerbo etc (little blue Tiffany boxes galore). We’ve used the boat infrequently during the past few years for only 20-30 days around Vancouver Island with the bulk of its time connected to shore power at a dock, but moved aboard full time about a month ago.
The scenario that stands out is as we were coming into anchor two days ago, we had been motoring for half a day and the batteries had charged from ~72% SOC to ~83% SOC (undersized alternator being replaced as part of the diesel project this winter), as we set anchor and idled back the alternator kicked down from ~1200w to a nominal level and the battery SOC immediately jumped to 100%. As an electrical simpleton this didn’t quite make sense to me, but I will now need to dig further. As the cerbo monitors and records battery temperatures, voltage and current flow through the shunt or inverter/charger continuously are there specific points that would provide the best insights?
Hi Ethan,
I don’t think that behaviour has anything to do with the batteries. Rather there are settings wrong in your battery management system resulting in it prematurely resetting to 100%, probably the expected acceptance voltage is to low so that the monitor saw the current drop and assumed the battery was full.
This is a common problem that I address in this chapter: https://www.morganscloud.com/2018/08/30/battery-monitors-part-3-calibration-and-use/
Note that this article assumes normal lead acid behaviour, so you will also need to take into account the above article as you program regulators and monitors.
I would also recommend reading this chapter about how lead acid batteries charge: https://www.morganscloud.com/2016/06/04/how-batteries-charge-multiple-charging-sources-too/
Hi John,
I have been a fan, for multiple reasons, of gel batteries for decades. At first it was Sonnenschein Prevailer batteries which I could get in the US and when in Europe. Then it was an East Penn brand and recently NAPA whose in-house branded gel batteries are made by East Penn (at least that was the case 4-5 years ago). They have served well, need no equalization, and have forgiven the occasional abuse that has come their way.
My best, Dick Stevenson, s/v Alchemy
2008 Outbound 46
” Bright Moments” crew do not share John’s high opinion of the Lifelines for cruising, antecdotaly shared by many cruisers in the South Pacific.
We replaced our 4 x Lifeline AGMs (1100 AH) from 04/2016 w/4 x Victron SuperCycles (900AH) in 01/24, in part on Ted Simper’s recommendation.
Purchased through a major NZ marine supplier. Upgraded the solar panels to 1075 w, run through Victron 100/30 & 100/50 Smart Solar Controllers and a Victron Smart Sense T & V monitor. Solar charge profiles set up as per Victrons limited recommendations. (essentially all battery charging comes through solar)
Passaged to Fiji in 05/24, all the issues we had with the Lifelines disappeared. The VSC’s charged faster, discharged w/o low voltage events from the use of windlass or bow thruster and operated at lower temperatures than the Lifelines. Never discharged < 50%.
The boat went on the hardstand in Whangarei mid-December '24, we did all of our upgrades & maintainence, dialed down the solar controllers and returned to Canada in March.
On return to the boat in Dec, we found the batteries at 42 C, two cases with heat distortion and 12.2 voltages.
I was able to screenshot 6 months of temperature & voltage data from the SmartSense monitor.
After much discussion with the Kiwi vendor we were offered a 50% warranty from Victron on the two deformed cases, the vendor offered the same on the other two, intimating that it might be contingent on a Victron replacement solution! (NZ $3100 battery only cost to us for one seasons cruising.)
With visions of a major curtailing of a planned NZ cruising season (ever tried to get much done in NZ in Dec. to Feb.?) we were able to book a Victron NG Lithium system install the second week in Jan. 2025.
We have since sold the boat, subsequent to 6 months of Kiwi cruising and a passage to Fiji.
For the first time in 17 years & 40 000 + nm of ownership, my first act on rising at anchor or passaging is not checking the battery monitor, but making that wakeup cup of coffee I've come to cherish….
I don’t know how long beforehand you were having issues with your Lifeline batteries or what those issues were, but you went 8 years on them (2016-2024)! That sounds like a fantastic testament to their longevity. Cycle count is certainly one factor in AGM life but age and exposure to warmer temperatures are other factors. I’ve always found I have to replace my AGMs somewhere around the 6 year mark and anything beyond that is just gravy.
Sounds like the Victron lithiums worked well for you and I’m looking forward to making that switch myself!
I had four Victron 230 Ah AGM Supercycle batteries that I had to replace after only one season. They were professionally installed with all Victron equipment, Cerbo, Quattro, shunts, etc.
Victron credited me for the cost, and I got four identical batteries that have worked throughout this season.
What you describe regarding the charging behavior could be the reason for the first batch’s short life?
Hi Jonas,
Sure, could be, although there are other possible issues including leaving them too long in a partial state of charge, which AGM batteries don’t like.
Anyway, if you have the same batteries now I suggest following my guidelines above for charging algorithms and not charging unattended. With all the reports we are getting I think my theory goes from “the preponderance of evidence” to beyond a reasonable doubt.
Thank you John,
I will alter the charging profile according to your suggestions.
I had to prove to Victron that I had treated my batteries well with the charging log and they had never been left more than a few hours in a low charging state. They dipped low however during night once they were damaged.
Many thanks for great content!
John thanks for a very cogent analysis that makes sense of a similar experience with 3 X 170Ah Victron Super Cycle AGMs installed by a professional marine electrician on our 44′ cruising yacht Zeehaen here in Australia in mid 2022. This house bank (now effectively dead), charged by 2 alternators (output combined via a 210A Sterling Power Alternator to Battery Charger) and 550w of solar (via Victron MPPTs) was very good for first 6 months cruising about 3000nm to Queensland and back, though the 510 Ah house bank was never discharged below about 80%. Life and a medical condition intervened resulting in much less usage over 2023-25, when vessel was mostly on a mooring (no shore power). While I’m a bit of an electrical numpty, I noted strange battery behaviour during two subsequent short cruises and a number of regular-ish maintenance visits, with highest recorded battery temp of 47 Celsius (measured at top surface of case). Cerbo touch continued to indicate 100% SOC but indicated voltage progressively declined over last 6 months from about 12.2v in May to about 9v on Oct, suggesting damage consistent with what you describe, though no deformation of the case is apparent. Was about to remove batteries for diagnosis by installer but based on your article think it might be more sensible and a whole lot cheaper to simply replace with conventional and deep cycle AGMs. I can replace the whole bank for less than the price of 1 Victron Super Cycle. This might not be conclusive evidence but appears consistent with what you describe.
Hi Guy,
Thanks for the report.
Sorry to hear it went so wrong. I think you are right that replacement is the way to go. Your experience seems consistent with my theory in that they worked fine when only subjected to shallow discharges.
Also unearthed (in pursuit of another topic) some relevant information here on the Victron Community page re Super Cycles overheating: https://community.victronenergy.com/t/victron-supercycle-batteries-overheating/15513
Doh! just realised you had already cited this one in your review!
We had the exact same problem, extremely overheated and the case swoll up, replaced it with a different AGM
Hi John,
The responses to your recent Victron AGM article flags for me how important it is to have some mechanism for the collection and distribution of information among the recreational cruising community, especially information about problematic habits of newly introduced gear, and especially those problematic habits that pose a danger to crew or to the boat.
Presently, it seems in casual observation, that the vehicles for getting information out largely relies on the accumulation of anecdotal reports that finally reach a density that it can no longer be ignored. This could and does take years and much damage can and does occur which might have been mitigated were there a reliable way for data to be collected and available for review.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Sure, a central reporting data base would be great, I don’t think anyone would argue with that. But how on earth would that happen and who would pay for it? Also, who would moderate it? Without moderation and verification I suspect it would just become another forum, or worse still a place where people just go to bitch about stuff.
An example of the problem of lack of verification and moderation is the cruisers who bitch about lifeLine AGM batteries being toast after only a couple of hundred cycles, but invariably we find they did not equalize them and left them for long periods in a partial state of charge.
And that brings up the point that if a product was being reported someone needs to contact the manufacturer and moderate their take on the issue.
One thing to identify a problem, quite another to come up with a viable solution.
Hi John,
Agree completely with all your points.
I do indulge in wishful thinking that pushes into the unrealistic: sometimes, though, a workable thought, even a solution, sometimes emerges from idle and shared speculation. I do wish the recreational marine industry would carry the weight in this area a bit. My take is that they drop the ball in their willingness to educate and protect the recreational boater.
My best, Dick
Hi Thomas,
Thanks for the report.
Aloha John and all the other salty sailors. Thank you for your depth of research and openness to changing your mind based on new evidence. I’m just adding my sad story to the list for posterity. I recently bought a 2019 Jeanneau SO440 that had a bank of Victron AGM 125s professionally installed. The surveyor noted the batteries seemed a bit warm, but was not overly concerned based on their location under a bunk. About a month later I noticed extreme swelling in two of the four batteries. I don’t have a bench unit to run all the tests, but I did confirm all the charging systems are setup and running appropriately. After much back and forth with Victron, they told me a swollen battery disqualifies it for warranty eligibility. I thought that was strange, but ran out of energy/time to fight. After this article and all the comments, I’m going to reengage. Photos of the deformed batteries I replaced them with LiFePO4 and don’t have to think about batteries anymore:-)
Hi William,
Sorry to hear that. It does seem that the evidence is now overwhelming so hopefully that, and that we now have an explanation of the modality that causes this, will persuade Victron to rethink your case.
We are real world case #4 John references above and Victron ended up replacing all three (3) of our Super Cycle batteries on warranty. We worked closely with OPE whom we originally purchased the Super Cycle batteries from. We replaced these batteries with two (2) 90 aH Victron AGM Gel batteries that we also got from OPE and we have not had a single issue.
I’m glad Victron seems to have admitted there was an issue based on pulling these off the North American market. The incident had me pulling my hair out that I had done something wrong in the selection and installation of the Super Cycle batteries.
Hi Bob,
Yes, I was pretty sure it was you when I saw the boat type and location, and was hoping you would come up with a fill. Good to hear the gels are working. The more I hear about gels the more I think that many of us, including me, made a big mistake going away from them, even though they can’t be equalized.
It looks like they may not be completely off the North American market. I can easily find multiple retailers advertising at least the smaller batteries (100Ah and 125Ah) as in stock and ready for sale. Maybe they’re just trying to sell remaining inventory to unwary buyers.
I installed 3 ea. of the 125AH, for the house leaving the Trojan AGM start, in 2023 prior to a Newfoundland trip. Have not had a problem, of which I am aware. But I don’t think I ever discharged below 70%. We had a largely windless cruise putting on lots of engine hours. 2024 had mostly day sails and one “local” cruise. 2025 she sat on the mooring as my wife had health problems. But for the cost of replacement, it would seem wise to do so.
The Trojan AES seem to make the same claims as the Supercycles so . . . . . . how long have they been on the market? Track record? Thx John
Hi David,
I think that’s smart. I’m planning to replace mine too, even though they are still working.
On the Trojan’s it’s only about a year since they came out, so I simply don’t know.
If you want a battery I can be 100% sure of, go with the Lifelines, just be sure to equalize them regularly (in the manual) and you should get at least 1000 deep cycles.
Thx John – Yes I had Lifeline AGM’s on a previous boat & they were still going strong when I sold the boat after 8-9 years
Thanks for this alarming and disappointing information.
I have been running a 560 amp Victron Super Cycle bank, a Victron 30 amp charger and 570 watts of solar since March 2023. So far no problems apart from lack of stellar holding power. I may have dodged a bullet so far due to the following reasons.
I sail in the spring and autumn. Days are shorter, the solar panels don’t produce peak output for long but in the Med there often isn’t a lot of wind and with the aforementioned fewer hour of daylight the engine has to be turned on to avoid entering new anchorages in the dark. The batteries are seldom full up or seldom below 70%. A lazy alternator may have turned out to be a boon here.
I don’t like marinas and I am scared of leaving the boat connected to shore power, even for a few minutes, having once returned to the boat to find a battery cooking off – the reason for the new Victrons.
Since I read your article I have been monitoring much more closely. So far the mains charger has behaved, going from Bulk to Absorbion to Float to Storage as advertised. And after 7 hours of motoring in bright sunshine all systems have gone to float. Batteries have remained at room temperature.
Nevertheless I have cancelled a planned increase in Supercycle battery capacity, ordered battery sensors for each battery and will try and eke out a few more years while monitoring much more religiously.
Hi Mark,
Seems like you have a good handle on it and should be fine. Clearly you understand charging and the problem, and that’s 75% of a solution right there. One suggestion: if you can, set all charge controllers to automatically time out of absorption and change to float after say three hours. Most (all?) viltron chargers will do this as well as Wakespeed WS500. That way the damage will most likely be limited it your batteries do flip into this strange mode.
Hi John,
I purchased a new Victron supercycle 170 Ah battery from a vendor in Quebec back in March this year with the intention of installing it in series with a new lithium bank as insurance against a load dump. After I recieved it, I checked the voltage – 12.7 resting – and put it on a 25A Victron blue smart charger. No issues as the charger cycled up through bulk, absorption and float very quickly as expected for a fully charged battery.
In June I decided to discharge the battery by ~40% at the 20 hr rate then recharge it – This as a ballpark capacity test before installing it in my boat. During the recharge from 60% using the Victron charger, the battery would not come out of the absorption phase and proceeded to heat up. I used an infrared thermometer to see a case temperature of ~ 42C (26C ambient). I stopped the charge and let the battery cool overnight. I restarted the charge and the charger went up through to float with no issues and no further battery heating. I repeated the same test using a borrowed Victron 15A blue smart charger with the same result – Battery would not come out of absorbtion and got hot to the touch. Once disconnected from the charger and allowed to cool down, the restarted battery charger worked as intended with no further battery heating.
I contacted the vendor, provided them with the aforementioned information and they opened a ticket with the OEM. Victron asked for specifics on the chargers used – (serial #s, photos of the charge profiles), pics of the thermometer readouts, etc. After ~ two months they issued me a full refund (less the shipping) for the battery. I asked them to send me a shipping label so that I could return the battery to them but they didn’t want it back.
Needless to say, I won’t be buying another Victron supercycle AGM battery.
Hi Matthew,
Great job on testing the battery and figuring out the issue, even better than I did. Way-smart to do that before installing it. Glad they took it back.