Testing AGM battery

Submitted: Tuesday, Jun 30, 2009 at 12:19
ThreadID: 70264 Views:2243 Replies:5 FollowUps:2
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How do you test a sealed AGM battery to check if it is still OK. While it charges up Ok it doesn't seem to hold the charge. In teh wet acid batteries you could test each cell to check them.
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Reply By: Gronk - Tuesday, Jun 30, 2009 at 13:01

Tuesday, Jun 30, 2009 at 13:01
Give it an overnight charge....leave it for 1/2 a day...check the voltage ( 12.8 ?? ) then take it and get a load test..
AnswerID: 372453

Reply By: olcoolone - Tuesday, Jun 30, 2009 at 13:40

Tuesday, Jun 30, 2009 at 13:40
We use an electronic load tester but if you want to do it at home you can connect a 55 watt halogen globe to a fully charged battery and see how long it takes to discharge the battery in hours and calculate the amps per hour.

This is a very crude way of doing it but if you have a 100 amphour battery that is fully charged and you only get 4 or 5 hours out of it then you know it is stuffed.

You have to remember a deep cycle battery will always deliver more amphours if the load is less... for example if you draw 1 amp per hour out of an 80 amphour battery you might be able to get 88 amphours but if you draw 20 amps out of the battery you might only be able to get 60 amphours of use.
AnswerID: 372460

Reply By: Maîneÿ . . .- Tuesday, Jun 30, 2009 at 15:46

Tuesday, Jun 30, 2009 at 15:46
Does it get dis-charged below 12v often ?
How old is it ?

Maîneÿ . . .
AnswerID: 372474

Reply By: bks - Tuesday, Jun 30, 2009 at 16:40

Tuesday, Jun 30, 2009 at 16:40
Only a few months old It would lose about 3/4 charge in 4or 5 days of not being used but charged up no problems.

Anyway I just took it back and they replaced it no questions

thanks for your help
AnswerID: 372479

Follow Up By: Gronk - Wednesday, Jul 01, 2009 at 00:37

Wednesday, Jul 01, 2009 at 00:37
I assume there is nothing connected across it ??
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FollowupID: 639797

Follow Up By: bks - Wednesday, Jul 01, 2009 at 10:02

Wednesday, Jul 01, 2009 at 10:02
No when I took it back they checked that there was no leakage. then just gave me a new one.
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FollowupID: 639814

Reply By: Member - Smiley Bill - Wednesday, Jul 01, 2009 at 10:51

Wednesday, Jul 01, 2009 at 10:51
Hi bks,

The proper procedure is to run a series of charge/discharge cycles over a couple of days and check the results.

A battery specialist would be able to help you with this.

SB
AnswerID: 372596

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