EV Trans Am

Just a couple more things tomorrow and hopefully we’re cruising by the afternoon to test everything out…

Today was a pretty productive day.  I made a bunch of wires and mocked up the fitment of the Raptor as well as the negative contactor box.  It will go where the catalytic converter was or possibly on the driver’s side, depending on routing of the conduit for the wiring. Also updated: wiring from switch to negative contactor, controller to motor cables, LV wiring to Raptor.

As part of my safety upgrades I’m making an enclosed front box that will contain all the HV connections except the Raptor and Motor. It’s a 12″ square by 6″ deep junction box. A plastic tray will hold all the parts then it will bolt to the box with a space below for all the bolts. This minimizes the number of holes drilled into the box the keep it watertight.

Since I’ve been driving Trans Amped it has been more difficult to work on it.  With it formally up on ramps and jackstands it was no problem to crawl under and do stuff.  Now I basically have to setup before working and I don’t like doing that.

So I haven’t done anything in a while but up next is removing the power steering pump and A/C and associated brackets.  That will probably be about 50 lbs out of the front end and will allow much more flexibility in my control board layout.  I’ve got an idea of making an enclosure where wires go in, wires go out and everything else is hidden.  Now that the car is moving and people are seeing it I’m going to be more careful about making the ability to tap into the full pack voltage, currently about a foot apart, a little more difficult.

Also on the agenda:

• Figure out a heater to use before it gets cold.
• Change the battery regulators wiring to 10 guage and relocate the regulators off battery
• Rear battery cover and carpet modification
• Relocate front battery regulators to a drier spot
• Fix the manual steering rack.  The alignment shop said it wasn’t centered and they can’t align it because the tie rod is all the way in already and the toe is still out.

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.

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.

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.