Sunday, October 21, 2007

BMS round one

I received my first prototype board from the fab house this weekend, and soldered it together.
The circuit worked the way it was supposed to, so I have ordered 3 more "final prototypes" that will have a few small changes, as well as a more polished look, with solder mask and silk screen and a slick oval shape. Once those arrive, I will probably borrow a few batteries and test the whole system.

TPS Report

Throttle Position Sensor, that is. I need a way to communicate to the motor drive that I want the car to go. Traditionally, electric car builders have used something called a "Curtis potbox", which is a variable resistor in a box, controllable by a cable hooked to the accelerator pedal. Trouble is, this device is made for controlling forklifts, and so isn't really suited to the abuse of thousands of stop-and-go cycles in a car.

Luckily, (newer) cars already have something very similar built in. The throttle position sensor tells the engine management computer to adjust spark timing and fuel mixture according to how much go the driver wants. It should be easy enough to adapt it to my purposes. The best part is, I got this one on ebay for $5. I think it came from a Ford. I 'm gonna keep all the useless-but-cool gasoline-related accessories on the module.