Peter’s E-914

I’ve been playing with the Parallax Stamp computer and have come to this conclusion:  it is fun. 

My main process is going to have these steps:

main:

read motor temp

if (temp < 130C) use high power, fan is off

else if (temp < 145C) use medium power, fan is off

else if (temp > 150C) use medium power, fan is on

goto main

This loop will only use 2 relays (one for fan, one for power control).  If I were to use low power setting, I’d need another relay.

I’m hoping to install the computer this weekend, but the weather may delay that (getting REALLY hot here in San Diego).  At the very least, I hope to replace the power supply for the BMS with something much smaller.

I’ve gone and purchased a small embedded computer to read the motor temperature and enable/disable the fan for the motor (www.parallax.com).  Nice stuff, very easy to work with.

However, since I now have this computing capability, why not use it to set the power settings for the controller as well?  The idea is that when the motor is cold, allow more power to flow into the motor, and when it is warm, turn down the power.  Azure Dynamics has 3 power settings available (max, norm, economy), and that is selectable by resistance into a line into the controller.

Hmmm.  This is gonna be fun. 

The kit I’ll be using for this project is available from Electro Automotive. It contains an AC motor, controller, battery racks, cables, and heavy-duty suspension. This is a bit lazy on my part, but I wanted to have most of the guesswork out of the way on this first project.

What’s interesting (to me) is that it requires the use of old-school 8 volt batteries. The kind that requires constant topping off with water. I asked why not use the newer sealed batteries, and the reply was, “You could, but you would get greatly reduced range and amperage.” Good enough.

Some other projects are looking into state-of-the-art (i.e. ultra expensive) lithium-phosphate batteries. These don’t explode, unlike lithium-ion batteries. They also cost around $2000 per battery. Ummm….don’t think I’ll go that route any time soon.

I ordered the kit on July 10 (mailed the check), so I can expect the kit to arrive within the next two months. The long lead time is due to the fabbing of the battery boxes. The motor and controller will drop-ship from Azure Dynamics. The other parts will ship from Felton to me as they become available.

Cheers!

Hi Folks,

I just bought a 1975 1.8 liter Porsche 914. It is sunflower yellow, and in pretty good shape. A few spots with rust (although I’m sure I’ll find more later). The transmission needs to be rebuilt (big surprise, eh?) and the engine has a bad case of vapor lock.

Having had the car for a few days, I figured I would start by taking out the old-n-busted alarm system. Easy, I thought. Until I tried to remove the wires leading into the cabin. Um. Ok, so how do I remove that panel from the back of the cabin? Time for the manual (again).

More later!

Cheers, Peter

P.S.  Some photos for you: