I was told it would be better to charge a leisure battery with a low amp charger - so I bought a £15 6 amp one, the battery started to lose it's holding capacity after a year. I think the cheap charger was overcharging & cooking the battery
I put in a split charging system and on days where I've done low mileage I use an intelligent charger overnight - once it's charged fully it checks the batteries voltage every minute or so
Think the intelligent charger is made by Seally and was just over £40