The Offshore Voyaging Reference Site

Q&A—New Lead Acid Batteries From Victron


Member Kimbal asked:

I’m looking at an ad on Yachtworld for a boat that has “New Victron Super Cycle AGM batteries – 3 x 125ah (2022) – Note: These batteries are a new type of AGM which approach lithium in some respects, and matches the Carbon Foam Firefly batteries performance – capable of up to 100% depth of discharge occasionally, and 60-80% frequently without damage.” Have you heard of this, and does it sound legit?


Yes, in fact that’s what we have installed on our new-to-us J/109, and testing at Ocean Planet seems to indicate that they do very well on deep discharges.

So far we have not used them enough to say anything really useful, although they are looking good after one season.

That said, it’s important to understand that Victron have two offerings with different strengths:

  • Super Cycle, which we selected because we have a very small bank and occasionally will need to take it a long way down, say when aboard for a weekend, but will be able to bring up to fully charged at our wharf when we get home.
  • Carbon Foam, which might be better for a long-distance cruising boat since they are more resistant to being left in a partial state of charge.

Do note though that all discharge cycles of all batteries (lithium included) reduce life to some extent (batteries are expendables) so claims like “and 60-80% frequently without damage” are simply not true. Like with Firefly, it’s important to read the fine print.

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Mark Wilson


Is the move from lead acid to lead carbon going to pose the same potential issues that Lithium does ?

Mark Wilson

Hi John

So, more expensive batteries but maybe fewer of them ?

Charles Hendricks

Wow, those carbon foam batteries seem really large for the capacity!

Charles Hendricks

It looks like 160ah in an 8d size. Lifeline 8d is 255. Unless I’m missing something here.

Thomas Baertl

Hi John first of all thanks for the fantastic input!
I am in the middle of replacing my batteries with Victrons.
There is a significant size difference
AGM Super Cycle 100 Ah: 260 x 168 x 215
Lead Carbon 100 Ah: 410 x 172 x 225 

Gives me more capacity!

Thomas Fox

I moved from Firefly Carbon Foam batteries to the Victron Super cycles in 2022. I struggled with the Fireflies for 2 years experiencing multiple failures. Each would be examined by the vendor, replaced under warranty and then fail again. Finally the US importer of the batteries acknowledged they’d stopped offering Fireflies due to issues with the supplier, and were unable to make good on growing warranty issues in a timely manner. They offered me the Victron Super Cycle batteries at cost and very low shipping cost and i jumped on it. 2022 was a much better year for batteries on our boat. I’d upgraded the charging system to accommodate the Firefly batteries – new alternator, added a charging regulator, replaced the shore charger, but still had consistent problems. Only 1 out of 5 Fireflies maintained capacity over 2 years. The Super Cycles have run well with no problems whatsoever.

Thomas Fox

Since you’ve mentioned them, I’ll also say that Ocean Planet was working with me on the Firefly warranty issue, and I felt like they did as best they could. They were very supportive, but getting nothing from Firefly in India. They also recommended the Victrons and got them to me quickly for a great price. I’m selling the boat I put them on this week so I won’t be able to comment on more than one season, but they were great this year.

Ken Grismore

Hi, I am looking at Victron Supercycle AGM batteries and I am wondering if you have any update on their performance or have any new information on their quality/life expectancy. I am comparing the 125 amp/hr battery to the Lifeline 31XT which is also 125 amp/hr battery. Which do you think is best for cruising, including extended periods away from the dock? Thanks.