Hi All
I have a leisure battery, 90Ah, which we had with a caravan. it has been left for 12months without charge, topped up with deionised water and put on charge for about 12 hours. when i have checked the voltage, getting 0.02.

Is it gone or am I missing the point, yes volt meter set to DC and 20v range

0.02v?!

What does it read whilst the charger is charging it?

What does it read whilst charging a known good battery?

Unless the charger is faulty it sounds kaput, although with patience you can sometimes revive a battery but I can’t remember how…google will know.

either your volt meter is broken or your batter
a battery is 50% flat at 12.4 volts and 0.02 is not a battery.
You could not get that low out a flat AA battery i would imagine
I doubt you will get close to recovering it if it is the battery

IME – lived on a boat anything around 10 -11 they do not recover from that as they wont hold a charge beyond a few days.

I’d say that battery is gone