Leisure batteries?

Feroda

Hi 

I am getting a bit frustrated by the short lives of our caravan leisure batteries. We bought a brand new battery when we purchased our caravan last spring, used it all year until October, and whenever we are not away it is plugged in to the mains at home,
as it was all winter. Have just been away for our first weekend and the battery died mid way through day 2 :-( It was £120 and I am loathed to buy another. Can anyone advise us on the correct way to look after the battery? Surely we dont have to bu a new one
yearly? Thank you