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A simple electric question


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Hi Libby,

It is most likely that the voltage and therefore current output of your on- board charger is higher than the output to your leasure battery from your vehicle alternator taking into account the losses incurred through relays and wiring, so your charger is probably working hard initialy. Vehicle alternators only supply single stage charging and there for only bring the battery to around 75% of its capacity.

Your on board charger if it provides muti-stage charging will bring your battery up full charge. The hum you are hearing will be from the transformer in the unit, this is not unusual, battery chargers always hum when delivering a high charge, and is nothing to worry about, just make sure you have it well ventilated. hope this answers your query.

Regards Geoff

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Also the Rapido charging system will charge the Vehicle battery after it thinks it has charged the leisure battery. I have been told that some times having a "old" leisure battery can confuse the electronics.


Maybe it defaults and charges both batteries at the same time and load causes it to hum.




PS check the water level in the leisure battery, mine falls at a slow but steady rate when charged on the mains.

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