Mains Charger
The unit that charges the leisure battery and applies a multi-stage charge profile when 230 V mains electricity is connected to the RV. The output current is typically offered in the 10–60 A classes and it sets the absorption and float voltages automatically according to the battery chemistry.
The device steps down and rectifies the 230 V alternating voltage and produces a stable DC output with a switching power stage. The control circuit applies the bulk, absorption and float stages in turn; some models correct the voltage for the ambient conditions with a temperature sensor.
Capacity is selected according to the battery bank. For lead-acid, a charge current on the order of %10–20 of the capacity is considered reasonable; for a 200 Ah bank a device in the 20–40 A class is suitable. A device chosen too small can never charge the battery fully, while one chosen too large produces needless heat and cost.
In an RV the mains charger often supplies the loads from the same housing as well; that is, while plugged in, the 12 V loads run straight from the device and the battery charges through it. Spending a night on a campsite hook-up is the quickest way to put back the share consumed by levelling and pump loads. Always verify that the chemistry setting on the device is compatible with your battery.
The context in which this term is used: RV automatic levelling guide