MY DIAGRAM  (how I installed the relay) DOWNLOADS

my wiring diagram

instructions and diagram which came with my relay (141K)

complete wiringdiagram for a late bay 73-75 (880K, one very large image)



Spooky's site







Installing a splitcharge relay in our campervan and wiring it up together with a second (leisure)battery. I did not use a leisure battery as I had a brand new 'normal' battery handy. If you have the choice go for a leisure battery.

I also decided to install a second fusebox in order to hook all my camping equipment up to that. The new fusebox will get a feed from the second battery, let's call that one our leisure battery .

You can place that new fusebox almost anywhere you like, a lot of people fit it under the rear seat. I put it next to the existing fusebox under the dash. That way I didn't need to route any wires to it, I simply swapped them over from the existing fusebox (all the camping stuff). Your main feed  however needs to be routed from the leisure battery to the new fusebox.


This is what I bought:
  • wires in all shapes and sizes, just in case. I always have some in the garage anyway but if you need to get hold of some try www.towsure.co.uk, they sell it by the meter and also have recommendations which wire to use for which job. They also sell split charge relays.

    For the main feed from leisure battery to fusebox I got myself an amplifier wiring kit which had a 50 amp cable with an inline fuse already fitted. This was 5 meters long and was exactly the length I needed. However you might want a bit more. You can also use the wire which is supplied with some relays of course.

  • 2 quick release battery terminals (again from towsure)

  • some cable ties

  • a split charge relay ;-) Mine is called Kombimaster as it is a split charge relay and fridge relay in one, I only make use of the split charge function though as I hardly ever run my fridge on 12 Volts. The relay cost £12.85 from a local caravan shop.

  • a (leisure)battery, I picked a brand new 'normal' battery up at a car boot sale for a fiver, I am sure it will last a while. After that I will consider a leisure battery.


Disconnect your vehicles battery earth strap.

I fisrt ran the thick red cable from near my leisure battery to the front of the car. I simply poked it through one of the existing grommets in the engine bay, then ran it underneath the car avoiding any sharp edges and securing it with cable ties and then up into the cabin right at the front. The inline fuse should be as close to the leisure battery as possible.

Next I fitted my fusebox in a convenient place under the dashboard. You can fit it whereever it suits you best. Then I fitted a spade connector to the end of my main feed and hooked it up to the fusebox. You will somehow have to split up the main feed several times, once for each point at the fusebox you want to use. I haven't found an elegant way of doing this yet, I simply looped another wire a few times.

Next I looked for a place to fit my relay and decided on the place the spare wheel used to be, on the left in the rear of the van. This is a place close to the leisure battery so I won't need to run miles of cable.

Now all you need to do is wire everything together. To do that you need to run a wire from the relay to a cable which is live when the ignition is on . I think it is even better to hook it to the generator warning light as this is only live when the ignition is on AND the engine is running. The generator warning light is often a thin blue wire somewhere in the engine bay.

You also need a live feed from the starter battery to the relay (the light blue wire in my diagram). You should use a fairly heavy duty wire for this and fit a fuse near the battery. My relay had the wire supplied and also instructions of how to fit it. On the photos this is the red wire which, together with the thinner blue one, runs from one side of the engine bay to the other one.

Then I connected the quick release terminals to the battery together with the green cable from the relay (the battery charge) and the red wire to the fusebox. I then made sure I had a good earth connection on my leisure battery and after checking all connections again I reconnected my starter batterys earth strap.

If everything is the way it should be then the terminal on the relay which has the green wire attached (leisure battery charge) only has current when the engine is running and should then read 13.8 Volt. Note that unless you connect all camping equipment to the new fuse box you will still be able to drain your starter battery. Your headlights for example will also still drain your starter battery unless they are switched over to the new fuse box, same goes for any other electrical equipment.

The whole procedure took me about three hours.

Any questions, suggestions, comments? Email me.

Happy camping!

wire used for main feed to fusebox

other stuff I used

the main feed goes through an existing grommet

wiring at the front of the bus, note the grommet which I fitted, the hole was already there (front bellypan removed)

the second fusebox fitted under the dash near the original fusebox the relay is now located where the spare wheel used to be before being put on the front of the van, the black thing on the right is the lid above the engine

here you can see the starter battery together with the constant red live feed to the relay and the blues cable which runs from the relay to the generator warning light or any cable which is only live when the ignition is on the finished installation

The KamperChatters web ring

© stoem 2001