Auxiliary Gas Tank and Auxiliary Battery

The last two days have seen some major projects finished. As I mentioned in a previous post I have installed a "split charge" system and an auxiliary battery. The "split charge" part refers to a special smart solenoid (a.k.a. a big switch; Cole Hersee part 48530) which isolates the start battery from the auxiliary battery when the voltage drops below a certain level. What this does is allow you to run electrical accessories from your auxiliary battery without depleting the charge on your start battery. This ensures that you always have enough charge to get the car going again, which is important if you are parked for a few days in a very remote area! I also installed the optional override switch allowing me to boost the start battery from the auxiliary battery should the start battery become depleted providing another level of safety in remote areas.

I had to figure out where to put the second battery. I briefly entertained the idea of cutting a hole in the floor of the truck and mounting it below the bed. However, this seemed a bit extreme and time consuming so instead I mounted it into the bed. This takes a bit of space but I tucked it up under the jack, behind the sloping bulkhead so it does not protrude too much into the bed.

I then made an aluminum shield to protect it from my soon to be extensive rock collection.

The batteries and the solenoid were all connected with 4 gauge wire with an 8 gauge wire supplying my accessories behind the dash.

As I've mentioned previously Land Rovers generally get very poor fuel economy. The standard fuel tank on an 88" is fitted beneath the passenger seat and contains 45 L of fuel. If you're lucky and you drive slowly with a tailwind you might get 300 km from a tank! This is unacceptable given the distances I will be going on this trip. Therefore I fitted an auxiliary fuel tank to double the amount of fuel I can carry. Many 88" Land Rovers came with an auxiliary tank under the driver's seat. This tank was filled by removing the driver seat and filling it through a screw cap mounted to the top of the tank. I wanted to have the second tank filled from the outside of the vehicle, just like the passenger side tank, so I copied the right side tank setup on the left. This involved having a frame outrigger welded on to hold the front of the new tank. This was done at the local welding shop using a prefabricated outrigger from Rovers North (Roversnorth.com). I then cut holes in the body, wheel wells, seat box and bulkhead to run the filler tubes. The only tricky part was cutting the rubber filler tube and splicing it back together with some muffler pipe so that it bends the right way.

A photo from the inside of the filler setup.

Here the pipes go through the wheel well. I formed a mud gaurd for the pipes in the wheel well just like the factory one for the passenger side. Because the tank was made for the right side the vent is on the wrong side of the filler tube. I had to wrap it around the big pipe to get it to the bottom of the filler. You can see the splice in the filler pipe.

I mounted a marine fuel tank selector switch to the front of the seatbox near the handbrake to switch between the two tanks and plumbed it all with 1/4" rubber fuel lines. I also installed a switch in the dash which allows me to switch between the two fuel senders. This allows me to, with one gauge, check the fuel level in both tanks.