Originally Posted by hellosailor
And, that his problem might or might not be because he needs to equalize the batteries, which LifeLine recommds--but other AGM makers expressly forbid. (Especially at the voltages LifeLine use.)
Actually, what it says on the sheet that comes with the battery is:
Equalizing should only be done when the battery is showing symptoms of capacity loss.
I have 4 of the Lifeline 8D batteries. The ability to mount the battery at odd angles was instrumental in my choosing AGM -- two of the batteries are stored on the small end. (That is, turned so they take up about 10x10 inches of floor space, but are almost 30 inches high.) Without this feature, I would only have room for two batteries, and so half the capacity.
The charge rate was another feature. You can push energy into an AGM faster, though I don't recall
exactly how much. The result is a shorter charge cycle. I have observed my 840 AH of AGM batteries accepting 160 A of charge current
at the beginning of the cycle. (The limiting factor was the 150 A battery charger
, and yes 160 > 150 but only by 7%.) Of course, this drops off quickly as the batteries are charged, but 160 A for 5 minutes is worth 30 A for 25 minutes, so it really does help.
The "last 15%" is a problem with any battery, but with my usual at-anchor charge regimen, it is only the "last 5%". That is, I charge up to about 800 AH from the generator
. I've always planned to get solar panels
to provide the last 40 AH/day, but it hasn't been a priority.
One of the reasons I wanted 840 AH instead of 420 AH (with 2 of 8D AGM) or 240 AH (with 2 flooded batteries installed by Beneteau) is that I can routinely discharge my batteries only to about 80% and then recharge to 95%. My peak power budget
is sailing at night in cold weather
(lights/instruments/heaters running), but even that stays above 50% discharge.
I'm happy with these batteries (and the associated electrical
system), but partly that is because my system is designed to make effective use of them. For example, if you get 800 AH of batteries and try to recharge them with a 30 A battery charger, you won't see the benefit of the higher charge rate.
I have not noticed any degradation over 2 years, but beyond the description above, I'm also pretty nice to them by spending a lot of time on shore power
. e.g. I was at the dock most of this summer, waiting for cooler weather
to go sailing. I'm happy with these batteries, but you can always ask me again in a few years.