…is MMM's electrical guru who spent his working life engineering forklift truck battery technology and has a gadgetladen A-class that makes the USS Enterprise seem basic
Motorhomes have both mains (230V) and 12V circuits and this is about the 12V side. However, we cannot forget that, when on a mains hook-up, your 12V leisure battery is being maintained in a charged condition by the mainspowered battery charger.
On a modem motorhome, all of the electrical equipment relies on a healthy 12V leisure battery to run it. Fixed items such as the cooking hob will have a 12V ignition system, the fridge will require a 12V supply if not two, the loo will require a 12V supply to make the flush work, and the space and water heating will, too. Then there is the lighting, which will be all 12V. And don't forget the electric step, these can be troublesome!
Then there are extractor fans in the roof, and the TV and satellite system, as well as USB charging points for your phones. Then, you may have inverters powered by the battery to generate 230V when no hook-up is available. Then add in solar panels and a solar regulator to recharge your battery when it's sunny.
Any and all of this can go wrong.
SAFETY IS PARAMOUNT
Before doing anything, always disconnect the hook-up lead from the motorhome. With the 12V side, always disconnect the negative connection to the leisure battery before doing any work on wiring and equipment, other than basic voltage measurements.
Why the negative? Both the starter and leisure batteries have their negative
