battery charging

[ianess]

Trying to recharge a battery from totally dead.  Charger needle flies off the top of the dial then after barely a minute drops back to zero.......this has been going on for a while now.  Will it settle down or am I flogging a dead horse?

[KebabMeister]

Are you using a trickle charger?  If it is completely dead then only a trickle charger will charge it.  Try it on slow charge.  Also did you check the battery level?  Did you have to top it up much?  It may need some electrolyte rather than battery top up water.

[honkytonkman]

My best guess is that the plates in the battery are buckled so it won't hold a charge. This often happens if a battery is allowed to die completely or has been flat for any length of time. Personally speaking were it me, I won't mess about, and would get a new one. But if you have transport in the meantime, there' s nothing to be lost from trying to trickle-charge it.

[MORELLO]

If it's not holding it's charge, it's knackered. Even though the alternator will put a charge through it when the engine's running, this will soon dissapate once switched off, leaving you with a flat battery and car that won't start. Jump leads and a trip to the garage. Stay away from Kwik-Fit...

[BillyNoMates]

I would say you are possibly flogging a dead horse. A lead-acid battery will never drop to zero on charge.

I suspect the battery may be totally flat and that your charger is overloading itself and switching off via a protection device. Does the charger dial go up to high again after a few minutes ?

You could persevere but beware of 'cooking' the battery while on-charge for hours on end, i.e. don't let it become too hot. Also keep a close eye on the electrolyte levels as they will become depleted with long charging time. This might keep you going for a while if sucessful, but look at getting a new battery.