If you search Google for Epsom Salts, it is possible to revive a battery.

You may even be able to top it up with Sulphuric Acid, Google it.

Be very careful with Sulphuric Acid, do not leave it lying around where children could drink it.

In the UK, it is a criminal offence to try to commit suicide. A friend of mine last week tried to commit suicide by drinking Sulphuric Acid, the Police are charging him next week.