I have a century 105 ah AGM battery, it was stored for quite a long time while building a new house (@7 months) the voltage dropped while in storage , it took 3 days to gain a charge of 12.6v and will not go higher.
From my reading the battery should float at 13.8v .
my questions are , should I be concerned? Do I need to replace the battery?
Is the 12.6v a 'resting voltage' disconnected from the charger, or the voltage whilst still on the charger? If the former it suggests the battery is perfectly healthy.
If however it is still on the charger & has not risen above 12.6v at all during the charging process it doesn't bode well.
Regardless of what the battery manufacturer says it should be floated at, the actual float voltage will be determined by the charger. My batteries also say float at 13.8, but my BCDC charger's float setting is 13.3v. I used to worry about this, but given the first set of batteries lasted 10 years I dont't think it did them any harm.
Currently my healthy batteries (2.5 years old) when not being charged, & with no loads connected will slowly drop from the float voltage, after being disconnected from the charger (car parked under cover/no solar input) to 12.6v/12.7v. When I go for a drive they quickly rise to 14.4v /14.5 v & then drop back to the 13.3v float within 10 minutes or so. Once home & parked under cover again voltage will slowly drop to 12.6v/12.7v again over around 24 hours or so, & remain at that for months.
-- Edited by Cuppa on Wednesday 27th of December 2023 10:10:51 AM
The 12.6v is its the battery disconnected when the charger (kickass 7amp 8 stage) is on it will read up to >14v. the battery is about 12 months old. I have not yet tried it on the solar panels or the car dc to dc Anderson plug.
The 12.6v is its the battery disconnected when the charger (kickass 7amp 8 stage) is on it will read up to >14v. the battery is about 12 months old. I have not yet tried it on the solar panels or the car dc to dc Anderson plug.
Smith
I'd guess it is probably ok then. You could do, or get done, a load discharge test to reassure yourself of your battery's present capacity . Needs to be done over a number of hours. NOT the same sort of load test commonly used for crank batteries where a high load is briefly connected to see if the battery holds up. Most battery places can do either test, but the high load test can be potentially damaging to a deep cycle battery. They'd probably need your battery overnight.
-- Edited by Cuppa on Wednesday 27th of December 2023 02:27:42 PM
I have a century 105 ah AGM battery, it was stored for quite a long time while building a new house (@7 months) the voltage dropped while in storage , it took 3 days to gain a charge of 12.6v and will not go higher.
From my reading the battery should float at 13.8v .
my questions are , should I be concerned? Do I need to replace the battery?
Smith
You didnt say what the battery is used for so even if it has dropped some capacity it may still serve a purpose. Being at low voltage for some time it may of sulphated but with an 8 stage charge I would be surprised if it didn't have a desulphation mode. Take a look at the manual.
If you do not have the equipment to do a capacity test then simply run somethings as you normally would to see if it holds up.
