Battery and charger advice please

JayEss

First of all let me explain that we have to have a gel battery in our van. There's a label in the battery box, several warnings in the manual and the dealer told us when we picked it up. Needless to say we stuck our old cheap leisure battery in and hoped
for the best. 

We use the solar panel to keep the battery charged and that uses the correct type of regulator. We only charge from the mains when we are actually using the van and haven't fried anything yet 

The current battery needs replacing and I want to get a good one but really don't want to lash out £260 on a gel battery. I was thinking about getting a CTek smart charger or similar wired in instead of the onboard charger.  Has anyone done this?  Any tips
or things to watch out for?