I spent a good part of the day today working on the PHEV kit. This time it had nothing to do with electronics or batteries. Today was about mounting the battery box in the trunk.
Previously, I had simply set the box in the back. This presents two problems. First off, in the event of a roll over, that box is free to play pin ball around the cabin which surely isn't good.
Second is what you see above. This is what the box covers up. If I get a flat tire with the box full of batteries and electronics its a huge pain for me to get the box out. If my wife were driving alone I'm sure she wouldn't be able to move it out of the way.
So, I had to think up something, hopefully simple, that might allow me to access the spare tire if the need ever arises. I went through a few fancy ideas that included air cylinders, a hinged system that lifted the box up. But, I finally decided on something very simple and inexpensive which was the goal. There isn't enough room for the box to simply hinge at the back corner and tilt up, the box hits the hybrid battery box which is directly forward of it. So, the box has to move towards the rear of the car while being lifted up to clear everything.
The solution I came up with was fairly simple. Add some wheels to the rear of the box to allow it not only to hinge upward, but also move rearward. So, I ran and got some 4.5" wheels from the lawn mower section of a big box store.
To mount them to the ~16ga box, I decided to weld some threaded rod to some 1/8" plate I had laying about. This will ensure that the weight of the batteries doesn't bend the box where the wheels attach.
Here is the finished assembly. There is one on each rear corner. They stick out from the box about 1/4". They are so far rearward because they have to allow the back corner to articulate without hanging up.
The Last part of the system is the lifting part of things. I think the box weighs around 200 lbs all together with everything in it, so its not light. So, to lift the box I decided for the moment to use some ratchet straps. I attach them to the hinge mounts for the hatch, and the other ends to the rear corners of the box. These allow you to lift each side up a little at a time. Once I actually get all the bits back in the box we'll see how hard it is to ratchet those things and if its too hard I'll probably weld some extensions on the handles to give more leverage. But, with the empty box the ratchet straps work great for lifting the box up and give plenty of room to get at the spare tire and tools.
However, the ratchet straps do have a very annoying flaw. Lowering the box back down is a big pain. You have to let a little slack down on one side, re-lock the ratchet strap, go to the other one, let it slack down, re-lock and back and forth and back and forth. The empty box bumbles around a little bit which isn't too nice like this. My question is, does anyone know if you can get ratchet straps (or something similar) that ratchets in
both directions? This would really be ideal.
I'm still working on exactly how I'm going to attach the box to the trunk so it can't move in the event of a roll over. I'll have to find some way to add some weld nuts or something so it can be bolted down. I thought about welding in some angle in the trunk but I'd like it to remain completely removable (and OEM parts go back in) in the event that I want to pull it out for whatever reason.