I recently made another post on the Autopia blog at Wired.com, and mentioned the car the electrified '94 Golf Kyle Dansie loaned me for a little more than a month. I give a summary of my experience with the car in the Wired post, but didn't have room to include an interesting experience trying to push the range of the car one night:
On a very cold early December night I tried to make it back from the Electric Car Company of Utah's shop. I drove about 15 miles from work to, to a parts store, and then to the shop, and charged the batteries while there. But I wasn't able to get a full charge before leaving.
Under ideal conditions, the car should get a good 40 miles to a charge. The drive home was only about 15 miles, but it was very cold (batteries don't perform as well in the cold), and I didn't have a full charge. I avoided the freeway since range goes down at higher speeds.
About halfway home, the accessory battery that powers the headlights, motor cooling fan, and brake pump started to die. The first noticeable effect was the dimming headlights. I soon realized that if the battery failed completely, I would be unable to move the car even if the main pack had power, since the contactor that keeps the high voltage power circuit on is powered by the accessory battery.
I stopped and disconnected the cooling fan to conserve power. The main pack had plenty of juice to make the drive, but the accessory battery barely made the trip. Ironically, I may have been better off taking the freeway, since the main pack probably would have handled the range, and the accessory battery would only have to run the headlights for maybe half the time.
Kyle has since installed a DC/DC converter which basically acts like an alternator for the accessory battery, keeping it topped off at all times with power from the main pack. The cars range will now only be limited by the main battery pack.