Sunday, September 16, 2007

Contact!

"MMmmph! Damn, that tingles!" -me catching some current from a battery terminal.

Yeah, I've started wearing rubber gloves now. I also disconnect the battery pack in more than one place when I work on the car.

I've suffered yet another component failure after the motor controller and it's the same old song: An old, and weathered part that probably outlived it's projected life-span. Luckily it was minor and relatively inexpensive.

The "main" contactor is a big, multi-hundred amp relay that connects the battery pack to the motor controller when you turn the key. It is both a safety and security device. The contactor that failed is the "Albright" brand. The terminals and large contacts are open to the air, and this allows corrosion, circuit resistance and commutation (sparking) to occur. A lot of EV'ers use these and they are durable but I don't like them. The moving, high-current parts are exposed to the elements and that just seems dumb.

I took a page from my Comuta Van days and bought a new Kilovac sealed contactor for the same price. It's a simple grey cylinder. The magnetic coil and the large contacts are permanently and totally sealed. The main contacts are also submerged in a sort of oil so every time you turn the key on and the contacts close, there is no arcing, sparking or commutation. They are rated for 1 million open/close cycles and something like 900 amps. It should last forever.

Installing it was a pain in the a$$. I had to remove the belly pan that protects the motor and everything else hiding in the engine bay. I had to use an angle grinder to cut away the old contactor bracket and drill mounting holes for the new contactor. Not difficult, just tedious.

And, once again I'm on the road. It's September now and the temperature has dropped as if someone threw a switch. Everything is cool and happy and I'm up to 3,200 miles so far.

I figure I'll get 7,000-10,000 more miles from these batteries.