Submitted: Wednesday, May 23, 2012 at 23:11
ThreadID: 95765 Views:2110 Replies:3 FollowUps:0
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Just recently fully charged my 110ah battery( so my charger tells me) and checked voltage about 15 mins after charging and was about 12.86v. Approx 2 hrs later was down to 12.8v(approx)further 2 hrs later down to about 12.72v left it til next morn and was 12.68v that night was 12.64v next morn 12.6v and since has been dropping on average over 3 days at about 0.04v per day . When charging and testing the earth(-ve) was removed from battery. Am trying to establish whether the battery could be on way out, or needs a decent de sulphating charge. i.e Fast Charge.....

Battery did have a very heavy( long discharge) about 4 weeks before this.

Any advice grasciously received.
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Reply By: NTVRX - Wednesday, May 23, 2012 at 23:30

Wednesday, May 23, 2012 at 23:30
I had a similar problem & was told the only way to check a battery is to put it under load......did that & battery indicated 12.4 before load & 7.0 under load. Battery in recycle skip!!
AnswerID: 486615

Reply By: olcoolone - Thursday, May 24, 2012 at 08:39

Thursday, May 24, 2012 at 08:39
What may be happening is there is a surface charge on you battery and over time this surface charge will decrease..... one of the reason for testing battery under load.

Or your charger may not be suitable for the battery type.

I would expect a full charged battery with a surface charge to show 12.9 to 13.2 volts if it has just come off a charger.

Or the top of your battery could have a semi conductive film (dirty, oily) across the top that will discharge your battery.

Or seeing your talking 0.1 to 0.2 volts from being full charged your meter your using to test the voltage may be out ...... we have seen cheap multi meter out by anything up to 0.8 volts and in some cases more.

Take your battery to a good battery reseller or auto elec and get them to test it properly .... the battery tester we use checks for a number of problems.

One thing you can do is place a 50 to 100 watt load across the battery for about 10 minutes and then let it sit for 30 minutes and them check the voltage.... this will remove any surface charge and let the battery stabilise.

You made no mention of battery type or what charger your using and how cold or hot the ambient temp was.

AnswerID: 486623

Reply By: Sigmund - Thursday, May 24, 2012 at 11:04

Thursday, May 24, 2012 at 11:04
Here's a methodof DIY capacity testing.

About to do it myself.

AnswerID: 486632

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