I'm looking into the possibility of installing some sort of mains charging facility for our division's first-aid treatment centre in St John Ambulance. Before you tell me off, it is very much along the motorhome line of design and may help others with motorhomes or doing their own conversions, so please hear me out!
Basically, we have the main vehicle battery in the cab, with a feed going to a second battery in the crew room (door on the left in the main body unit). This second battery is used for 12v lighting, communications radio, water pump, gas powered heater and to 3x 12v sockets for phone chargers etc. The feed between the two has a cut-off switch, so that the main battery cannot be drained when the vehicle is in use at events.
However, since we had a satellite tracker fitted we have had serious problems of both batteries being drained (when both left connected on purpose) when the vehicle is left stationary for a period of time. We have a small solar panel from my caravan in it at the moment but it's not really powerful enough.
My question really is, is there a charger device that we could install that is permanently connected to the main battery that we could wire to an externally mounted socket we could easily access to plug into the mains?
I have seen on a 52 reg. Vauxhall Zafira a 16Amp connector flush-mounted on the rear of the car to accept a mains lead for charging the vehicle battery, and when I asked the owner about it they said it was manufacturer installed. Would anyone know the charger device that uses?
This would be a lot easier than a normal battery charger or removing the battery to charge due to the location & size of the battery and also the varied crew who drive the vehicle - simplicity is the key really!
Sorry for the long post but thought the background info may help!
Install a 12V DPDT (crossover) relay powered from the ignition light. The common connections go to the vehicle battery. The normally closed connections go to a bog standard battery charger (or a fancy one if you want unattended charging). The Normally open connections go to the second battery (observe correct polarity) via an inline fuse.
When the engine is stopped, the relay is inactive and will connect the charger to the vehicle battery.
When the engine is running, the relay is activated and
1.disconnects the charger from the van battery and 2. connects the van battery in parallel with the second battery - charging both.
Would this do the trick??
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personnally if its only the mian battery you are wanting to keep charged up when not in use, i get a ctek maintainance charger get the fly lead fitted somewhere easy access glove box etc the its just a case of connecting the charger to the fly lead turn on and press mode button,
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Topic: Mains charging dual-battery setup?
