Just another battery box

I’ve spent the past two weekends figuring out the best way to mount twenty batteries in the front trunk. I had this crazy idea to stack the batteries two rows high, but after an email from Mark Urban (he built another electric Boxster) I decided go the same route he did and make a funky shaped box that stuffs all the cells onto a single level:

The strapping is there because I need to compress my cells a little to get them to fit. As they have been sitting for a bit, they have swelled a little. My figures are crossed hoping this doesn’t effect the cell capacity too much.

Replacing the “gas” pedal

For this project I’m using a hall effect accelerator pedal instead of the standard “pot box”.  The hall effect pedal is more robust both mechanically and electrically.  However, using it means I need to replace the entire pedal assembly. Here’s the original pedal:

Removing one screw and sliding the pedal straight up released it.



The new pedal need a spacer behind it so when it was fully depressed it would clear the floor. So I made a spacer out of some 3/4″ HDPE I had laying around. I drilled and tapped a couple holes and voila! A the new accelerator pedal is mounted:


I might try and find some carpet to fill in the hole left by the old pedal.

Getting rid of the tank

Now that the gas tank has been emptied and had a chance to air out I decided it was time to pull it out. I thought I could make a couple slices with the Saws-All and it would pop out. Boy was I wrong! I spent a total of four hours cutting, yanking and prying before it finally came out in about five pieces.

Note to anyone else doing a Boxster conversion, let me recommend leaving the gas tank in. It’s a pain to remove and it doesn’t actually gain you much more usable space.

The only thing it really did was make it easier to bolt the accelerator to the firewall.

Busting out the welder

It’s been a few years since I’ve done much welding. So I did a test piece before starting on my actual battery boxes.

It turned pretty well (a little blobby but strong with no major pits or cracks). So I went ahead and put together the boxes that will each hold 8 cells (for a total of 16) in the engine compartment. I made the boxes quite tight:

If I slide this last cell in, I’m not sure it would come out easily. I still need to sand off the corrosion.

I just set them in place to get a general idea how they’ll fit.


No more gas

There are a number of small tasks that need to be done that don’t rely on other stuff being done first. So when I only have a few minutes to work on the car, I try and tick one of those tasks off the “todo” list. Tonight’s task was to drain the fuel tank.

It was relatively easy. A little googling turned up instructions on hot wiring the fuel pump by jumpering the appropriate relay. With a little rubber tubing and my 5gal gas can, it took about 20 minutes to empty the tank and transfer the gas to my other car.


The wheels on the bus go round and round…

This week, I replaced the slave cylinder, mounted the motor/trany assembly and connected the axles. Some good progress…

Here’s a picture of the motor mounting plates I had laser cut:

They are 3/8″ steel and mount to the steel face plate I already had.


Here’s a quick video of the wheels spinning with a 12volt battery:

I connected up the cables to the shifter and did a quick test to make sure all the gears worked.  They seem to be fine.