Dry battery revival?

[flymo]

I have a totally dry bike battery, before I replace it can it be refilled with suitable water and charged? Or does it need an acid refill?

[garynortheast]

It'll need a refill with the correct quantity of acid. No guarantee that it'll work afterwards if it's been on a working charging system with no electrolyte in it.

[Sid Squid]

It'll need acid, the reaction won't start with just water. Whether it will come back to life depends largely on why it's dry and for how long it's been that way. I've revived a couple of batteries from a similar state, but I wouldn't rely on it.

[flymo]

couldnt source any battery acid locally that quickly so took a chance and refilled with boiled/cooled water from the kettle. It took a full charge and seems to look ok so far. I'm not expecting a particularly long life so may need to replace it anyway in the long term.