Sunday, March 16, 2008

Longest trip

I went 27 miles on a charge, but I had to stop to let the batteries recover, and limped in at about 20 mph max speed. Seems like anything over 22 mies is pushing the limit. Otherwise everything is running good. I am working on a vacuum system for the brakes.

Sunday, February 24, 2008

The stats

I created a spreadsheet to track the energy use of the Metro. It can be viewed here:
http://spreadsheets.google.com/ccc?key=pqkXLgw4FcoLQX9v1NgZjbQ&hl=en

Tuesday, February 19, 2008

What the.....

What you see here on the right is a relay. On the left is a 1000 ohm 10 watt resistor. It's wired so that when the key goes to the first position the circuit across the contactor is closed through the resistor. That way there is no sudden rush of current through the contactor when I turn the key to the second position. I did this because the contactor had stuck a couple of times.

I'm on the third charge cycle. After 21 miles my hydrometer read 1.185, which would normally be about 45% charge. This may be close. I could have up to about 9 KWH of capacity in my battery pack. I put 5.54 KWH of juice in on this cycle. That = .26 KWH/mile. I will try to go around 30 miles on the next charge, monitoring with the hydrometer, and see how it goes.

I'm figuring out the shifting. I'm driving mostly in 3rd, then at about 30 I can pull it out of gear and it slides easily into 5th.
It has good pick-up and is fun to drive.

Monday, February 11, 2008

How much per mile?

Here is my preliminary calculation;
I used a device called a "Kill-o-watt" to measure how much Juice came out of the wall.
After a full charge I drove 9 miles. Then I did another full charge. the meter said that I used 2.55 kilowatt hours.
My electric bill says I pay about 20 cents/kilowatt hour. So the 9 miles used about 51 cents.
So around 6 cents a mile.
If I got 40 miles/gallon at $3.30 gallon that would be 8.25 cents a mile. Not a huge difference.

Moving out

Saturday
We wanted to build a box for the rear batteries and install the on board chargers before the final move out. Here is the box open:
and closed:
Matt found a great place to install the on board charger on a plate at the front of the engine compartment.Can you see Matt's fingers, putting in one of the final bolts?

Sunday, January 27, 2008

The Maiden voyage

Saturday

We have the batteries secured in the front and are preparing to wire the final cables.Looks like rush hour around the controller with all the wires and cables.
The safety recommendations are to place plywood over areas not being worked on to prevent accidental shorts.
Also to be safe, before the final wiring we put the car up on blocks: just in case something unpredictable happened.
OK, all wired up, everything double checked. Key in the ignition, turn the key: NOTHING. The contactor did not close the 72 volt circuit. We got out the volt meter and tested the current to the contactor. It had 12 volts. We had tested the contactor before installing, and it made a healthy click when wired to 12 volts. We are scratching our heads. We gave Wilderness EV a call, and were lucky to reach them on the weekend. They said to test the circuit with a light bulb. Luckily Matt had a light probe in his bag of tricks. We tested the wiring we were using and sure enough, not enough current to light the bulb. We then started testing other unused wires, until we found one that lit up the light probe nicely. We wired the contactor to the good wire.
Maiden Voage take 2: Key in the ignition, turn the key: volt gauge reads 72 volts. Put the transmission in 2nd gear, push on the accelerator pedal, the wheels turn. High fives!!
We take the blocks out clean up and get ready for the first drive.
Here we are breaking the bottle over the bow before it slides into it's first trip.
We climb in, buckle up. Turn the key, 72 volts on the meter. 2nd gear, let out on the emergency break. Push on the accelerator, and start gliding out of the carport in almost total silence. Our trip starts with a steep downhill. The brakes without the vacuum pump need a lot of force. Then a stop sign, total silence. Pull away smoothly. The controller is functioning nicely with the motor. We cruise around for about 5 minutes, on the uphill the Amp guage goes up to about 300 amps.
On flats about 50 to100 amps. We reverse it back into the car port. The reverse seems a little trickier to control.
I turn the key off. Still have 72 volts. uh oh! For some reason the contactor is not releasing the 72 volt circuit. We unplug it, still 72 volts. we take of one of the cables to break the circuit, and then remove the contactor. We test it and now it seems to work.
Well almost a completely successful test drive. I am contacting Wilderness EV to see if they have a solution for us.

Sunday:
We spent the morning getting the rear battery rack ready. We will construct a plywood box to go over these batteries.


Tuesday, January 22, 2008

Secure batteries

We used some threaded rod and various bits and pieces to secure batteries. On the right you can see the new battery for the 12 V system.
We were able to reuse this gromet to protect the wires where they go through the firewall towards the 3 batteries in the rear.