Up and Running again!

The story with the Kelly KDH14500B controller ended about 400 feet after it started. I took my first test drive the day or two after Thanksgiving, and the car sluggishly rolled about 400 feet then stopped with a low voltage error flashing on its front panel. The voltage at the controller was 128V.

People at Kelly Controller were helpful in doing some debugging, but in the end they concluded that all the measurements I made were at nominal values, so if the controller still wasn't working then I should send it back. It took me a while to get it out of the car, boxed up and shipped, but I eventually did, and then things slowed down for Christmas. I finally received a replacement controller on Tuesday (Jan 5th), and I found time to reinstall it this evening. The controller booted up just fine, so I took it out for a couple short test drives around the neighborhood streets, sticking to streets above my house where I knew I could roll the car home if it quit again. Overall, things seem positive at this point.

Performance-wise, this controller is much slower off the line than the 72V unit was (it was a KD72500). In fact, when starting on any sort of a grade, 2nd gear is absolutely anemic and seems like a bad idea... First gear may actually be required to get the car moving. But once rolling in 2nd gear, the KDH14500B seems pretty good, and I got it up to 30 mph (on a slight downgrade) quickly with what seemed like less effort than the 72V system required. Further observations will be forthcoming as I venture out on longer trips.

Finally, some stats on the battery heaters. The car has been sitting here without moving for the last 5 weeks while the controller was out of it, and I had the batteries plugged in on float charge that whole time... which means the heaters were running too, keeping the batteries warmed to about 95'F. In that time, the Kill-A-Watt meter measured 198 KWh. That's about 40 KWh / week, or about 240 W average power consumption. 90 W of that is the chargers floating the batteries, which means the heaters are drawing about 150 W on average, or 1.25 Amps. Given that the ten 35W heaters would draw 350W if they were running continuously, I surmise that they are running about 40% of the time. In 5 weeks, 200 KWh @ $0.09/KWh costs about $18 for 35 days, or about $15.50 for a 30-day month. That's $15.50/mo. to keep the batteries float-charging and the heaters running in average 38'F weather (avg temp from NOAA for Dec. 2009 in Seattle). Seems like the heaters are running a lot, so I might have to look at tightening up my insulated boxes a bit.