I left one of my leisure batteries on charge for too long in the garage.
I've just gone in there and it stinks of rotten eggs!
So disconnected the battery and checked the cells, bugger they are low.
This battery is only about 6 months old and to be honest I never bothered checking the cells before.
So ive just topped it up and will charge it for a few hours to see how it goes.
I reckon its knackered though.