Battery System in a Caravan, Fifth Wheel, or Trailer
The 12-volt system in a caravan or trailer is powered by a 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 caravan trailer is being towed. Small AC loads, such as a TV, or a temporary load, such as a Microwave oven, can be powered by an inverter attached to the house battery system.
When the trailer is plugged into shore power, excess AC power is automatically shared with the DC converter, and the 12-volt house battery system is recharged. State of Charge (SOC) monitoring will be advantageous when free/dry camping without shore power. Solar panels are often used to supplement stored battery energy when free/dry camping and to provide maintenance charging during trailer storage.
Maintenance-free spill-proof batteries are highly desirable.