Question

Recently, after driving our 2003 Compass Avantgarde 400RL the voltage from the leisure battery was low to non-existent - the pump runs slow and the boiler won't stay on. The first time we were aware of this we struggled with dim lights for the evening but in the morning all was ok again. I presume this means that the battery is not at fault. However the next time we drove somewhere the same thing happened. Any ideas?

Answer

It appears that the leisure battery is being drained whilst you are driving and this points to an alternator or relay fault associated with the engine. If you were hooked up to the mains electric supply when you were parked then it is likely that the leisure battery became re-charged.