Leisure battery restored to health

[tonytech]

A workmate brought his Caravan Leisure battery (110Ah) in to me last week because he had let it go really flat over 12 months and couldnt get it to charge.
I tried several conventional chargers, all decided the battery was either faulty or fully charged (6V)
I tried connecting the battery to a 12v 6A Laboratory power supply for 12 hours, then back on to one of the Lidel battery chargers. Success.

I've left the battery standing for a week and the voltage stays around 12.8 v
I've run a 2A load for 24 hours ( battery voltage stayed above 12v)

I'm not sure this helps folk, but just be aware that some chargers are stupid.

T

[CovKid]

The LIDL one is very good - can vouch for that. My stepfather owns a new caravan and also bought the LIDL charger on my recommendation. Earlier this year I was about to throw away one of those battery booster units (stood unused for two years) and decided to break it apart and see if the battery was any good. Flat as a pancake but sure enough, a couple of days on the LIDL one and it not only brought it back to life, its held the charge ever since. Plan is to fit it as an alarm back-up battery but use it regularly for testing various 12v components - handy thing to have around.

[kevtherev]

Me too
I can vouch for the Lidl..
rescued a starter

starter registered just under 3 Volts before I charged it

[tonytech]

The point is the lidel charger wouldnt charge the battery until I'd had it on a power supply over night.

T

[ghost123uk]

Tony, your technique there is very similar to one many technicians use to re-vitalise NiCad batteries when they have gone completely flat.

Some of these "clever" chargers are too clever and miss read what a flat battery "should be" so a brute force charge to get it up to somewhere like what it should be, then a "conditioning" charge on a clever charger is good practice (as long as you take care not to boil the battery on the Lab charger and blow yourself up !!!! )

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Reminds me of those garage airlines that won't pump up a tyre if it is TOO FLAT (I know some have a button to press in that eventuality)

[CovKid]

Yup - exactly right. If voltage falls below a certain level you'll need a bit put in to give the other one something to bite on.

[ghost123uk]

Yup - exactly right

Same as trying to bump start a vehicle equipped with an alternator and a completely flat battery.
The alternator will not "kick in" unless there is at least some voltage present in the battery.