1 year ago I started driving the vintage electro daily. I've logged 4600 miles without any trouble. That's about 80 full charge/discharge cycles. The battery is specified for 5000 cycles down to 80% original capacity.
Assuming 20 mpg as an ICE vehicle and $3 per gallon it would have consumed $690 of gasoline. At 315 Wh per mile and $0.10 per kWh I only paid $145. $545 of fuel savings over 1 year! Plus no oil changes.
The AC was repaired one more time at a shop then slowly went out again. It must have a refrigerant leak, I plan to have it repaired at the shop again. Having AC in an old car is awesome. Windows rolled up! It worked great before it went out, instant cool.
I plan to plumb cabin air into the trunk for cooling purposes. Just a little hole and a fan between the rear speakers behind the back seat. When the summer sun beats down on my trunk the batteries in there get too hot and my BMS shuts me down to prevent damage. Also the DC/DC converter overheats. As a workaround I leave my trunk cracked and try to park under trees.
I've began starting out in 2nd gear. The torque of the electric motor makes starting in 1st gear very jerky. If I floor it in reverse the wheels really tear out. It's fun to do when giving someone a ride.
I'd like to take some more data on efficiency now. I think I've come to drive it better, primarily by staying out of 4th and 5th gears. When I stay in 3rd gear my top speed is around 55 mph. But I occasionally use 4th to get up hills.
I do not miss pumping gas!
Tuesday, September 23, 2014
Monday, March 3, 2014
log
Step 36: Rewire BMS current sensor and test heater. In step 29 I mentioned that I needed to rewire the new school current sensor so that it would work better. I did this using proper shielded cable and it no longer gets stuck. Now I can log some driving and hone my efficiency.
There are 2 routes I can take to work, one via highway 71 which is mosly 55+ mph, and one via Barton Creek which is mostly 35 mph. The Barton Creek route is ~1 mile and a few minutes longer but 18% more efficient going to the office and 5% more coming home. In addition to the speed I think other differences are stop sign or stop light placement with respect to the bottom of hills (bad!).
I was also able to test my heater. It draws 900W from the battery and appears to increase energy per mile by 12% (reduce range by 12%). It was in the mid-twenties and the heater kept the car warm enough that I wasn't freezing but there is room for improvement. It was a strange sensation to smell electric heat in a car.
Notice the peak powers on the heater run are lower than the other runs. That's because the battery was near freezing and cell resistance goes up with cold. So its harder to get the amps out and I have to drive in a higher gear to get the same speed.
There are 2 routes I can take to work, one via highway 71 which is mosly 55+ mph, and one via Barton Creek which is mostly 35 mph. The Barton Creek route is ~1 mile and a few minutes longer but 18% more efficient going to the office and 5% more coming home. In addition to the speed I think other differences are stop sign or stop light placement with respect to the bottom of hills (bad!).
I was also able to test my heater. It draws 900W from the battery and appears to increase energy per mile by 12% (reduce range by 12%). It was in the mid-twenties and the heater kept the car warm enough that I wasn't freezing but there is room for improvement. It was a strange sensation to smell electric heat in a car.
Notice the peak powers on the heater run are lower than the other runs. That's because the battery was near freezing and cell resistance goes up with cold. So its harder to get the amps out and I have to drive in a higher gear to get the same speed.
Wednesday, February 19, 2014
heat
Step 35: Make heat. A space heater and a 12V fan can deliver. The heating element of a space heater will run off the direct current, it plugs into an extension cord under the backseat. The extension cord comes from an Edison fuse on the battery posts of the motor controller in the trunk. By tapping off the motor controller we can leverage the existing power relay that feeds the motor controller. The heater will only work when the key is in the on position.
The fan of a space heater requires alternating current so I removed it to improve air flow. Then I cut the back out of the space heater and mounted the 12V fan, face removed. It plugs into the cigarette lighter.
The unit tucks under the dash or can sit on the passenger floor. I get 500W of heat on low and 900W on high. If 900W is not enough I will shorten the heating element to reduce its resistance, this will increase power. The element can support 1500W.
It will have to get cold again before I can test it. In the summer it will be stored in the trunk.
The fan of a space heater requires alternating current so I removed it to improve air flow. Then I cut the back out of the space heater and mounted the 12V fan, face removed. It plugs into the cigarette lighter.
The unit tucks under the dash or can sit on the passenger floor. I get 500W of heat on low and 900W on high. If 900W is not enough I will shorten the heating element to reduce its resistance, this will increase power. The element can support 1500W.
It will have to get cold again before I can test it. In the summer it will be stored in the trunk.
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| heat! |
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| left over parts |
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