Whilst I dont want to complicate your thought, I have too say that leisure batteries per se are not that great. They are often described as leisure batteries but are no more than a good car battery.
I would look for some true deep cycle batteries that are used in forklift trucks and renewable energy systems. These have very thick plates and normally last a great deal longer than leisure batteries.
Also make sure whatever you buy that you never let your battery go below 50% of its charge. If it does it is only likley to last about 25 charges and it will be duffered.
A great battery is a Trojan. Slightly more expensive than a leisiure battery but will last years if you look after it.
I hope that helps |