Battery System in a Van Conversion, Camper or Class C Recreational Vehicle (RV)
The 12-volt system in a Van Conversion or Class C ‘Camper’ is powered by a separate bank of ‘House’ batteries (typically 100 Ah to 200 Ah capacity), which will be deep-cycled regularly. The 12-volt system powers the DC lights in the living space and the water pump. It also enables startup of the 3-way refrigerator, which then runs on gas when ‘free/dry camping,’ or AC when on ‘shore power,’ or off DC while the vehicle is being driven. Camper van house batteries are charged by the alternator, in addition to, but after the starter batteries have been charged. Undercharging of the house batteries can occur due to an overloaded alternator, undersized cabling and voltage drop across the battery isolator/combiner.
The AC system is powered by ‘Shore Power’ or a small generator and supports items like TVs and rooftop air conditioning. An inverter can also power AC loads like 3-way refrigerators, microwave ovens and TVs or, if installed, an inverter-charger. House batteries need to support the surge current of the inverter during load startup. When the camper van is plugged into shore power or the generator is running, excess AC power is automatically shared with the DC converter, or if installed, the inverter-charger and the 12-volt house battery system are recharged.
The starting batteries must deliver high cold cranking amps (CCA) consistently, operate in high and low temperatures and withstand road vibration. High-Cycle Reserve Capacity is required to support dashboard electronics and GPS with the engine off.
Battery failure is most commonly caused by acid stratification, extreme temperatures and destructive over-the-road vibration. Acid stratification naturally occurs in flooded lead-acid batteries and leads to a decline in capacity and charge acceptance. AGM and acid mixing technology for flooded lead-acid starting batteries will mitigate acid stratification. AGM technology, or equalization charging by the inverter-charger for flooded lead-acid deep-cycle house batteries, will mitigate acid stratification. Maintenance-free spill-proof batteries are highly desirable.