My Unimog campervan has both a 24 volt and 12 volt electrical system. Power is stored in two 12 volt 200AH Elecsol batteries (in addition to the two 12 volt Varta vehicle batteries). These two batteries can power the lighting, refrigerator and heating system for about four days of normal use when fully charged.

The two batteries are connected via three 500 amp key switches (A). Distribution is then via two master 24 volt fuses (B) and one master 12 volt fuse (C).

One of the master 24 volt fuses feeds the microwave oven the other feeds nine fussed circuits via the main fuse box (D).

The master 12 volt fuse feeds three fused circuits via main fuse box.

This 12 volt supply is only used in emergencies. The primary 12 supply is via a 24 to 12 volt converter.

After the failure of my 24 volt microwave in China I added a 2000 watt inverter powering an electric kettle and a very cheap ($40USA) mains microwave. A far better solution. I also fitted a more powerful battery charger (25 amp) and a small Honda generator.

Main electrical distribution.


The batteries are charged in three ways:

  1. Whilst the engine is running via an X-Split electronic split charger from the alternator.
  2. When mains power is available via a Mobitronic 24 volt/8 amp charger (above) Now 25 amp.
  3. If the sun is shining via the four roof mounted solar panels.

Because the solar panels provide sufficient 24 volt power most of the time there is no mains distribution within the campervan.

Main panel front (under construction).

Most electrical power is controlled via the main panel above the dining area. This panel contains (from left to right) a loud speaker, the heating controller (top, not yet fitted), three Zig control panels, the solar controller (top, not yet fitted), the fresh and waste water level gauges, the radio/cassette player and the other loud speaker. Beneath the controls are two adjustable task lights.

!2 volt radio (rear)
Main panel complete (front)
Mains (240 volt) inlet under floor rear Inverter and solar controller
Two 12v 200AH Batteris and main fuse panel. Alarm connection box.

As well as a 25 amp battery charger I have also added a 2000 watt inverter (24 volts DC in, 230 volts 50Hz out) mounted in a sealed box with vents to the outside rear. Note that this inverter takes nearly 100 amps at 24 volts on full load and therefore requires very heavy wiring.

This inverter powers the microwave oven (800 watts out, 1500 watts in) and an electric kettle.

Because the inverter uses about 0.6 amps even with no output load I have extended the "on/off" switch wiring to allow the inverter to be switched off when not in use.

In order to provide power when remaining in one place for several days and when solar power is insufficient I fitted a small (900 watt) Honda EU10i generator. This supplies 230 volts 50Hz power to the 25 amp 24 volt battery charger. The generator is mounted in a lockable cage bolted under the body behind the rear right wheel. The generator can be used in situ or placed on the ground to reduce the internal noise level. The generator was invaluable in Iceland.

Home pageLast updated 2003-11-08.