Charging up

Almost every item in the habitation area is powered by 12V DC from a leisure battery – this is probably your most critical and finite resource, as nothing works without it. The leisure battery (or batteries) powers the lights, fridge, water pump, TV, toilet flush, gas hob ignition and many other systems. The vehicle battery is the battery that starts the engine, powers the vehicle’s headlights and everything to do with the base vehicle. The two sets of batteries are normally separate to avoid the risk of leaving a habitation device on and flattening the vehicle battery, leaving you stranded. Some campervans are also fitted with solar panels.

The leisure battery has a fixed capacity – for example, 100Ah. There are various scales to rate batteries, but the K20 scale (run over 20 hours) is the most helpful. So, on the K20 scale a 100Ah battery can supply 10A for 10 hours (or 5A for 20 hours).

In practice, a lead acid battery can’t be flattened to less than 50% without damaging it, so it’s best to simply divide the K20 rating of a lead acid (or AGM) battery by two to work out the real-world usable power. So, a 100Ah battery can safely supply 5A for 10 hours. Modern lithium iron phosphate batteries can be discharged safely beyond 50%. 100% is said to be possible – but these are more costly than lead acid or AGM batteries. As you have a finite battery supply, all campervans have a built-in charging system.

This is activated when you plug into the mains hook-up bollard and will immediately start recharging the leisure battery. Most leisure batteries are also charged up when driving, through a splitcharging system. Campervans have a selection of 230V mains electrical sockets, but note these only work when you’re plugged into a mains hook-up, not usually off the leisure battery.