2nd hand AGM - How to recondition?
Submitted: Tuesday, Apr 08, 2014 at 20:02
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neimad19
Hi all
Today I went and picked up a Ritar(?) 100ah agm battery from a guy who was selling it through Gumtree. I plan on using it as my Aux batt on a hiace campervan I'm building.
The battery was housed in one of those battery box's with cigarette lighter outlets and a few gimicky LED battery meters ect. He always had it hooked up to a 40w solar panel whenever he used it and (according to him) only used it for camping lighting and to charge phones, computers, ect. He mentioned it's around 9 months - a year old and hadn't used it in about 3 months.
I brought it
home and threw the multi meter onto it - Less than 2 volts!!
I'm no expert on agm's but I assume having it drained that low can't be good for the battery.
I have a cheap car battery charger that charges 11.5v @ 2.5amp, should I hook it up to this and let it sit for a few days? Or hook it up to my hiace alternator and let it idle for a few hours?
What's the best way to go about 'reconditioning' the battery back to normal?
Also, worst case scenario it was drained completely flat like this a few times, how bad could the potential damage be? Throw away type damage?
Cheers,
Damien
Reply By: Sand Man (SA) - Wednesday, Apr 09, 2014 at 07:37
Wednesday, Apr 09, 2014 at 07:37
Damien,
Ignoring the fact that the battery is probably cactus, the charger is also not putting out enough voltage, or current.
To charge an AGM you need around 14.2v. Charging at 2.5a, the battery will take forever to reach full capacity even if healthy.
A smart charger that has a maintenance mode may recover the battery, but I doubt it.
10.4 volts is dead flat and after a good charge, the battery should be sitting at 12.8v.
A charger outputting 15 amps is a good starting point and it should be a multi-stage charger to charge the battery properly and maintain it.
If the battery has had even a few total discharges, it may beyond recovery. If the plates have calcified to the extent that a "maintenance" charge won't recover it, then it is a throw away.
Take it to a battery place and have them
check it. They should do this for no cost and with no obligation to purchase a new battery from them.
Sorry for the bad news.
AnswerID:
530143
Follow Up By: - Johny boy (NSW) - Wednesday, Apr 09, 2014 at 08:27
Wednesday, Apr 09, 2014 at 08:27
Sand Man just saved me the time to write pretty much exactly the same thing ,so I will agree and second his comments!
Good Luck .
FollowupID:
813015
Follow Up By: John and Regina M - Wednesday, Apr 09, 2014 at 08:53
Wednesday, Apr 09, 2014 at 08:53
Sandman
Why should they
check the battery for no cost?
They may, but they are perfectly entitled to charge for their
services. I respect this option.
FollowupID:
813016
Follow Up By: pop2jocem - Wednesday, Apr 09, 2014 at 09:55
Wednesday, Apr 09, 2014 at 09:55
"Why should they
check the battery for no cost?"
Simple good business practice. If the battery is cactus, and I suspect with a resting voltage of 2v it is, the guy is going to possibly buy a battery for his
camping needs.
The Battery World that I have done business with has never charged for taking maybe 5 minutes to put a gauge on a battery for me or any of my family or acquaintances.
As far as the possibility of recovering this particular battery I think the chances have been pretty
well covered but I guess there is nothing to lose by giving a it a shot. I wouldn't try the car charging system though. You could be up for some new components. A multi stage charger would be my choice.
Cheers
Pop
FollowupID:
813022
Follow Up By: rooster350 - Wednesday, Apr 09, 2014 at 10:29
Wednesday, Apr 09, 2014 at 10:29
I had 2 100ah d/c batteries tested by Battery World in
Darwin for no cost , they were pleased to be asked to do the the job because it would mean a sale if the batteries were faulty, fortunately for me they were o.k.
FollowupID:
813026
Follow Up By: Member - Toyocrusa (NSW) - Wednesday, Apr 09, 2014 at 10:33
Wednesday, Apr 09, 2014 at 10:33
Have to agree with you there Bill. It is just plain good business practice to not charge. Even if the owner does not buy a battery off you, they will still tell their friends and eventually someone comes back to buy. Regards,Bob
FollowupID:
813027
Follow Up By: get outmore - Thursday, Apr 10, 2014 at 07:13
Thursday, Apr 10, 2014 at 07:13
To
check the battery it needs to be charged
FollowupID:
813098
Reply By: Member - Phil G (SA) - Wednesday, Apr 09, 2014 at 22:17
Wednesday, Apr 09, 2014 at 22:17
When a battery has been deeply discharged (I expect by having something powered off it when stored), it takes a huge effort to get it working again. The internal resistance becomes very high, so the battery will take little charge initially. If you hook it up to your car's alternator, it's unlikely to take much charge, because I expect it has been 2volts for quite a while.
If you hook up a normal battery charger, they usually cut out when they detect the high resistance. What I'd normally do, is hook the battery up to a 13.8 volt power supply and let it sit for a week hooked up to get some charge back into it. Then see how it goes on a multistage charger. If the voltage is OK, then try running a camping fridge off it and see what happens. If the voltage drops off pretty soon, the battery is no good, and you have wasted your money. If the fridge works OK for say a day, then keep the battery fully charged and use it.
AnswerID:
530195