EV Trans Am

Granted, all it did all day was sit there, but it did at least go.

After last night’s unadventurous drive to dinner I opted to fill ‘er back up and make the slightly longer trip to work, about 15 miles round trip. I took the back roads to keep it under 45 since I was engaged in traffic.

Went 15 miles, voltage when complete was 154. Starting was 168 so it did pretty good as far as range. Charging back up now. It’s been about 3.5 hours at 13.5 amps so we’ll see where it is.

Tonight we went out to a pizzeria that is 5.8 Google miles away. The pack wasn’t quite topped off from a quick lap around the neighborhood the other night so we started at 166 V. Finished voltage was 155.3 so we used 11V to go 11.6 miles, about a volt per mile which is easy to remember. I don’t understand why everyone says 300 watts per mile, I suppose because pack voltages vary.

So instead of saying I need 300 watts of power to go 1 mile, to me it makes more sense to say I’ll consume 1 Volt to go one mile. Voltage is potential so I like the idea of saying I’ve got 30 volts to use at 20% discharge so at 1 V/mi I can go 30 miles. Less as the pack is depleted, but about that.

Besides, who has a meter for watts installed in the car to tell them how much fuel is left, seems everyone uses a voltmeter for “fuel” and an ammeter for instantaneous use.

So after the clunk videos we opted to be brave and took Trans Amped to dinner at Route 46, about 2 miles away with backroads we could take.

For those without a Trans Am, when the weather looks like this you take the t-tops out and go cruising. Just like the good old days but all electric.

Now I’ll get technical. We figure we went about 4 miles. The batteries weren’t fully charged because of the earlier testing in the neighborhood (I did that about an hour before dinner) so the pack voltage was about 172 while charging, so probably 168 resting. After the 4 miles the measured voltage was 162. so if we used say 8 volts to go 4 miles I can take the pack down to 125 (80% of 156) that means I have about 45 volts worth of safe go juice. At roughly 2V per mile that means I’d be able to go 22.5 miles. I’d expect the mileage to decrease along with the pack voltage though so probably a little less. Yay onboard charger! This is the lowest the pack has been so I’m interested to see how long it takes at 13.5 to recharge. I need to get that 220 line installed. I do have an anniversary coming up soon…

Keep in mind the speedometer and other gauges don’t work (only the ammeter) so I’m guessing at the distances and even the volts. But it’s inline with what I’d expect. Speeds were probably 25-40 mph which is typical for my driving, maybe closer to 45 though. Amp draw in 4th at ~35 mph was a pretty stead 75 to 100. Pushing the pedal a bit more and the amp draw would increase to 800 at the highest I saw. Still haven’t tried full throttle, I’m enjoying it working after a year and a half of build and don’t want to break something just yet.

Here is a video I shot today. Troubleshooting the rear end clunk has me confused and since it only happens when you are driving and I am the driver I figured I’d tape the camera under the car and then drive. Out of 4 minutes here is 14 seconds. Second 10 is the interesting one. I’ll sort through the rest and decide it any more is worth posting. It’s a pretty cool video just to see the driveshaft spinning. It goes pretty dang fast for being under 20 mph most of the time.

For viewing understanding: The video is rotated 90 degrees. The ground is to the left and the inside of the rear driver’s side tire is on the top of the screen. The camera is mounted to the passenger side lower shock bolt looking at the rear pumpkin with the torque arm behind the driveshaft. Hope that clarifies.

Today I upgraded the switch that turns on the negative contactor. It’s a bright red, lighted rocker switch that should be easy to remember to turn off. I also reinstalled the interior console and rerouted the emergency rip cord to come out by the driver’s right knee. I’ll attach a red handle or something to it soon.

Also cut off a couple bundles from the engine wiring harness. I think I only cut wires I don’t need. I don’t have most of the sensors anymore so I don’t see why I would need them, but they may go to something I wasn’t thinking about. I did that so I could easily run the plugs to the transmission. Now the speedometer should work, as well as the reverse lockout.

I’ve got a plan to cleanup the rear battery area by remote mounting the regulators in a box next to the charger.  If I move them I can then seal up the batteries and still be able to see the regulator LEDs flashing.  That will make things look more professional and keep some road noise out.  For the past few test drives we’ve had the center console removed so we can see and hear the pavement through the shifter and the battery racks.

I can also remove the stock power steering pump from the engine bay.  I’ve got one battery that is always last and removing this pump will allow me to access it better to charge it up as a single battery so it doesn’t drag the rest down.  I like the idea of an electric A/C compressor as well, so that would free up a good amount of space under hood.

We think it’s just some driveline slack. Another test run and it was pretty smooth. The clunking happened very briefly after a few stops and restarts but overall it was much smoother. I think it’s just that the clutch isn’t there to smoothly engage the power to the rear so it gets it all at once.

Now to clean up some of the wiring and button things up. I need to reconnect the speedometer cable so I can see what kind of range I can get and how fast I go.

Trans Amped is reinsured and roadworthy!

So when the Trans Am’s mighty LT1 bit the dust, the car would buck pretty badly as the engine backfired and sputtered. I wonder if something in the rear end broke during all that and that is the cause of the clunking, not my driveline angles….

I’m thinking it might be a broken axle given feedback about the wheel changing directions rapidly before the car moves from a stop. Neighbor Mike replaced his axles, I wonder if he still has the old ones. I already have his springs in the rear. I wonder how much I can cannibalize from his Trans Am.