If I try to start my 18HP ride on mower it just clicks, but if I just put battery on charge for 5 minutes it will start.
It could be a duff battery but its only 1 year old

RUSSELL JONES, June 2009

You are indeed down on battery power....its best to leave the battery on trickle charge overnight if you can - 5 minutes really isn't long enough. The battery would normally last longer than one year, so long as its fully charged up when you put the machine away at the end of the season.

John, June 2009