I have been considering where to mount the battery for months. It makes sense to install it close to the engine due to the voltage dropping as it travels down the cable and you need all the power you can get for the starter motor. Problem is that most of the weight of the car is at the front due to the engine and gearbox location, the rear wheels are pretty much only held down by the weight of the chassis and rear axle. It is therefore extremely likely that the rear wheels will want to lock up under braking.
Ok then lets put some weight over the rear axle then. You may recall my mounting two spare wheels right at the back of the car, they do not weigh a huge amount but it all helps. So what I now want to do is install a battery box under the rear seat, right in front of the axle. Ah, one of the shock absorbers is in the way as is the brake rod. But if I mount the battery anywhere else, it will be too low which is bad for playing in the mud. Eureka moment – if I take out all of the wood behind the front seats, I can pop the battery box roughly into place. As you can see there is not much room. Granted I could have a smaller battery box but I want the ‘option’ of being able to fit a bigger batter in case I need it.
I then put all the wood back, crawled under the car to move the box about and marked the wood accordingly being careful to observe the potential movement of the rear axle.
Below you can see the wood back in place. This is 20mm marine plywood and is pretty strong, but I know that I will have people in the back of the car bouncing up and down in an attempt to get the rear wheels to grip in wet mud so I want to add a strengthening brace just behind the battery box. The round hole is so that I can gain access to the rear axle as the oil will need changing at some point and the petrol tank will prevent access otherwise. The strengthening brace is 30mm angle iron securely bolted to the wood from underneath.
In the picture below, the steel strengthening brace has been installed (but you will never see it). But you can see that the wood has been protected against moisture with all fresh cuts stained to match the rest of the wood. The temporary cross head screws have been replaced with more period looking Stainless Steel slot head machine screws and the electrical cables have been run in too. The earth cable is very short in length whereas the positive cable has to run all the way to the front of the car so that is almost twice the size to minimise the voltage drop. The battery terminals are not yet fitted but they use a bolt on fitting to suit the cable ends.
The backseat can now start to be built up with a panel the backrest cushion will mount onto made from 20mm marine ply. This will be cut to match the shape of the rear of the car and gains me a handy storage area behind the seat. The seat base will spread the load across the panel the battery is fitted into serving a double purpose. The piece of wood shown is too small and does not reach the sides of the car but you get the idea.
You will know the exhaust pipe runs along the outside of the car and it will get hot. Potentially very hot. Anyone sitting in the back has a seriously real chance of leaning their arm on the exhaust pipe which I imagine would not be popular. Also entry into the car will be stepping in over the exhaust – more opportunities to warm up body parts. The answer is to wrap the exhaust pipe with a protective layer. Historically people used asbestos rope simply wound around the pipes but I have gone for exhaust wrapping tape which although not exactly period in manufacture – its much safer. Time will tell if the VSCC scrutineers dont like it and make me revert to something more period. You may have noticed it in the picture above but this is the whole pipe
A good days work…