I have a heavy duty 12v tractor battery that has been allowed to run flat.
When I put it on a mains battery charger the casing of the battery becomes very warm to hot even on a trickle charge.
Is this normal or is the battery beyond recovery?
Is their any simple way to know if the battery will hold a charge long term?
I'm using a Seeley starter/charger; Model 'professional' 'Superstarter' 420/1
Any advice appreciated
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Check the battery voltage 24hrs after charging using a good quality digital voltmeter, anything less than 12.8v means that further testing is required.
A cheap hydrometer should help, you can buy the green - go / red - no go sort of thing for a couple of quid. They're not that accurate but a bad cell will be detected.
A heavy duty discharge tester is a good bet, a dud cell will bubble as the tester is applied.
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Im not battery expert but think the advice above (whilst its good) is not quite accurate and needs bit further explanantion.
Charge the battery on the lowest setting for 2 hours or so. Take voltage reading before starting and at end of charging. leave it to stand for 2 hours and take furhter reading. repeat this over course of 2 or 3 days and assess whether battery is holding increasing charge. If not it has gone open circuit and is probably dead; certainly beyond diy help.
If rate is increasing increase charging time gradually unti it begins to hold charge at around 12.5v after a couple hours off charge. then and only then should you you contemplate using a discharge tester.
A specific gravity test can be done along with voltage tests but is only really of use when battery is charged (like discharge test).
Voltmeter readings as a guide (after charge and stood for 2 hours or more)
Up to 12.3 volts battery is of no use.
12.3 - 12.4 battery is in poor state of charge
12.4 - 12.6 battery is probably ok, as long as it holds this reading for a period of time (week or more) without any further charge.
over 12.7 battery is in overcharged state and unlikely to last , opossibly has bulged sides etc. if so do not attempt to use it.
Hope this helps
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Thank you both for the valuable advice.
Could you suggest type of Voltmeter or Brand?
Is this the kind that electricians use with the dial on the front?
or maybe a link to a website that sells same?
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I would have thought you would have got by with a cheap and cheerful multimeter - around £10, probably from your local hardware or electrical shop.
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Does the charger indicate current? I would have thought that a true trickle charge wouldn't give enough current to get a large tractor battery as warm as you suggest.
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Yes Martin, it indicates about 7-10 on the lowest charger setting.
The scale is 0-49, I presume this is current in Amps.
I tried another similar battery which is near new. It initally shows about 5 but then goes down to Zero after about 15 minutes on the charger. This battery doesn't get warm.
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If the battery has sat discharged for a long time then it will have suffered badly. Bits of the plates can fall off as sediment and short things out. If another battery behaves properly then I'd give the other one up if it doesn't recover after a day or so on charge. I wouldn't call 7-10 amps a trickle charge though. My charger would be hard pushed to give 10A at maximum.
Martin
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It appears its beyond recovery after been flat for too long a period.
The outer case heat may be the result of some shorting going on in the innards when trying to charge it?
Ta for the advice
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