Can this battery be rescued?

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Sandgrounder

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While my boat, 19ft 3/4 decked keelboat, I have been using an automatic bilge pump temporarily installed. When I went to the boat on Saturday it was clear I had a problem: the pump was entirely submerged and the croc clips which link the wires from the battery to the pump leads were touching. Clearly the battery had shorted and was utterly discharged. I was told by the owner of a neighbouring boat, who seems to know about these things used a meter tested the battery and seemed to detect some life and aid that the battery would be OK after a good long charge - " a few deep cycles" I think.

I took the battery home and have had it hooked up to the trickle charger I normally use. Even when completely discharged, the charger indicates that it is charging the battery; this time there is no indication of any activity. Have I wrecked the battery or is it recoverable?
 
It's possible that it's OK if it was only a day or two. I have a pro battery tester at Liverpool Marina if you'd like me to test it.
 
Sandgrounder said:
While my boat, 19ft 3/4 decked keelboat, I have been using an automatic bilge pump temporarily installed. When I went to the boat on Saturday it was clear I had a problem: the pump was entirely submerged and the croc clips which link the wires from the battery to the pump leads were touching. Clearly the battery had shorted and was utterly discharged. I was told by the owner of a neighbouring boat, who seems to know about these things used a meter tested the battery and seemed to detect some life and aid that the battery would be OK after a good long charge - " a few deep cycles" I think.

I took the battery home and have had it hooked up to the trickle charger I normally use. Even when completely discharged, the charger indicates that it is charging the battery; this time there is no indication of any activity. Have I wrecked the battery or is it recoverable?
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What do you mean by "no indication of any activity"

A trickle charger may not recover a completely discharged battery. You may need a charger with a greater output current, appropriate to the size of battery.

To be really successful you may need a charger with a "reconditioning" stage although that is not guaranteed to work.
 
Bad news: If it has been sat shorted for any period of time it's probably dead, or at least has serious permanent capacity loss.
Good news: You didn't have a fire when it shorted.
 
Generally any lead acid battery that has been completely discharged has been damaged, and may be irrecoverable, but sometimes you can revive one that was previously in good condition. The problem with a lot of modern battery chargers is that they are designed so that they do not switch on and charge any battery that is already below a certain voltage. You may need to find an old charger that has no such electonic trickery built in, or one designed with a reconditioning stage. The bad news about that is that I have one which was still incapable of starting to recharge my stepson's car battery when it had been discharged to read only 3.3 volts..
 
As said the charger may be too smart for it's own boots. If you don't have a charger which will charge it (old style) then try coupling it in parallel with your car battery. Not directly but via a large 12v high wattage globe. This will limit the current. When (and if) the globe goes dim you can bypass the globe but by that time it may have enough voltage to enable a charger to be used. Just a few minutes will often get a battery voltage up. if it does not go dim battery is cream crackered. Be careful of sparks and of course don't flatten your car battery. Have the engine running.
Is the battery dead? Only time will tell. good luck olewill
 
Had a simelar incident with my float switch, intermitent short.
May have been responsible for two failed batteries last season.
Only copped it when I saw a dim glow on the auto switch led.
My second hand agm,s seem to be on the road to recovery.
One holdind well but other has a faster rate of voltage drop.
I,m useing a 16 amp Ring smart cgarger and hope both can be recovered completly.
Getting rid of the float switch, only 4 years old, and going back to isolating the batteries when leaving the boat.
 
Sandgrounder said:
It worked. 10 minute blast linked to car battery and it is now charging. I'll leave it on trickle for the rest of the week and then see how it holds out. Many thanks for all the advice. Much appreciated.

Simon
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You have just learned that the sh itty clever chargers we have today wont charge a flat battery, they are protecting themselves from delivering too large a current.
Stu
 
I've had problems in the past with modern chargers. The OPs best chance is to hook it up to an old one which has no 'smartness' just an ammeter on the front.
 
ghostlymoron said:
I've had problems in the past with modern chargers. The OPs best chance is to hook it up to an old one which has no 'smartness' just an ammeter on the front.
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I have two 200ah and one 120 ah battery connected to a smallish solar panel about 400x400 it produces 18 v no regulator I have found that all of the batteries are now dead .is there any way to recover them
 
Go back to the advice offered by William H to the OP. I would have suggested this plan and I'm glad it worked and the forumites were thanked for their trouble as well!Makes us feel good and wanted!
 
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