Hi Jamie,
The text book way to do what you ask is to remove the battery from the caravan and take it home and connect a Ctek battery charger which adjusts the voltage / amp requirement of the battery. Charge the battery on a wooden board - not a concrete floor.
Its a bit of a pain to keep removing the battery, but at least you know the battery is in tip top condition and the Ctek will make sure of this.
The xs 3600 is a good all rounder - and usually charges up the battery in about a week for a 110A/hr, depending on how good the battery is, and what A/hr.
There are more Ctek chargers that take less time to charge a battery - but they are more expensive.
The Ctek is designed so that you can leave it permantly connected to the battery - it does the rest.
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