Fitted new starter battery in May this year haven't used the van for a couple of weeks, tried it over the weekend and battery was flat. Jump started it and took it for a run and was all ok. I have a leisure battery fitted and on checking the van over found there is a clicking sound coming from a small unit next to it -would this have anything to do with the battery going flat?
If you have a meter you could stick it in series and see if current is being drawn off the battery when everything is switched off. The old CD radio I had used to drain the battery when it was turned off at the front - I fitted a switch under the edge of the dash to switch it off completely.
If I leave the face plate on my stereo in the bus, it keeps the Bluetooth active even though the stereo is turned off with a blank display, and it draws a quarter of an amp. Enough to flatten a good battery in about a fortnight. If I take the face plate off and put it in the little box, no problem. In your case, I suspect the clicking box is the leisure battery splitter relay having a bad day because the leisure battery is also flat, so every time it connects, the main battery voltage dips and so the relay opens again.
