treating agm battery bank

[libra]

My battery bank is made up of agm batteries. 24v @ 1000 ah. When they are charged they seem to rest at 26v. This seems where they sit even with no load for a few days. They generator is putting out 3-4 kw per day.

The data that I have read and what I can interpret from the manufactures spec

is that they can be charged up to 14.4 (28.8v) to keep them at peak.

These are old batteries so would expect them to be less than prime.

Every few weeks I kick in the charger and bring them up to 28.6v for a few hours.

I realize that you don't equalize agm batteries but am I really doing any good?

Don't want to kill the golden goose.

Libra

[zap]

You're probably not hurting them.  .2 volts is a good error value unless you know you're meter is more accurate than that.  14.4v is a bit high for the average AGM but by the time you figure in temperature then it's right in the ballpark for every AGM and if your manufacture says 14.4v then I'd take them to that.  A deep discharge can sometimes help.

Amps in and amps out is a better way of determining the health of your bank.  I've seen plenty of small AGM that would show 13.2v and have zero capacity.

All of the people on this site that actually know batteries will tell you the best thing to do is "work them" which seems to be what you're doing.

Working them will kill them as will letting them sit.  You're "golden goose" is dying as is most every battery from the day it was made.

[SparWeb]

Nice set of batteries.  Depending on the make, the recommended float voltage can be higher or lower than other types.  I "work" my batteries too, though I do it over the objections of some on this site.  I persist with deliberate exercising of the batteries because they only get charged at 10 amps and discharged at 100A - but the cells are capable of delivering over 500A and the manufacturer has published capacity ratings and lifetimes that go that high.  So a little exercise is probably the best thing to deal with conditions like stratificatoin of the electrolyte and imbalanced changes building up on the plates.  All stuff I don't really understand, but if the manufacturer shows there's no harm, there's no harm right?

Someone recently told my about catalyst caps that are available from Battery Research.  I haven't got any yet, but I'm still reading up on the topic because they do offer a way to prolong AGM battery life. These guys also state that the occaional over-charge, for short durations, is not harmful either.  I'm not sure who to believe, but some people have posted details of their own tests on the internet and the results are so far positive.  Big AGM batteries are supposed to last over a decade so the truth cannot really be told for another few years, yet.

[zap]

I've heard of the recombination caps for flooded but I've never hear of them for VRLA.  Some very interesting reading on that page.

Thanks for posting that Steven.

[libra]

thanks for the reply. Will have to read that article carefully.

Libra