Friday, February 8, 2008

Christmas in February

The shipment from Azure Dynamics arrived today. It was all attached firmly to a pallet and plastic wrap / strapped together. The total package weight was 330 lbs:

Here it is, all unboxed / unpacked sitting on the driveway:

I ordered the AC55 motor (weight: 106 kg / 233 lbs):

...a DMOC445 controller (same as in the Volt914):

A 312-V DC-DC converter designed to work with a backing battery:

And the interface kit, composed of this cool switch (which controls motor direction & power as well as regen braking and, just for fun, the electric heater):

...and this regen braking relay & wiring:

...and a throttle potbox & wiring:

...and the main wiring harness to the DMOC445:

...and various and sundry misc connectors, etc. for the above:

So, off to order the rest of the stuff. There are some basic upgrades to the Jeep:

  • Front disc brake replacement
  • Rear disc brake upgrade
  • Suspension upgrade (a 3-inch "heavy-duty" lift kit)
  • Cable switch to replace 2wd->4wd vacuum switch
As well as a long list of parts for the conversion:
  • 2/0 or 4/0 welding cable for high-current wiring
  • Charger
  • (maybe) 26 battery charging regulators (if I go with AGM)
  • 26 batteries (AGM or flooded)
  • Cable lug ends
  • Heater core
  • Power steering pump electric feed
  • Power brake system vacuum system
  • Lots of L-bar and square tubing to weld together for various supports
  • Material for battery boxes (possibly plywood, still debating)
  • Gauges, shuts, and such
  • Fuses & circuit breakers
  • Connectors, nuts, bolts, grommets, kitchen sinks, etc.
The Jeep upgrades are on order. Still evaluating the rest.

Thursday, February 7, 2008

Parts on the way, and motor notes

I got notification from Azure Dynamics that my controller, motor, DC-DC converter, and interface harness have shipped. They should arrive in Colorado tomorrow. I'll put pictures up when they get here; in the meantime, here are some notes on why I selected the motor I did.

Basically, a sports car (like the volt914) is designed with a gearing ratio that encourages higher RPM. A SUV, like the ElectroJeep, is heavier, and the tranny typically has a lower gearing ratio. So, I was looking for low-RPM torque, and not too concerned with high-RPM perf. Here is a chart I made that combined two charts from Azure (along with an estimated "AC24L" motor that TimK mentions in this post on his 914ev blog). This plots torque vs. RPM. Note the *much* higher torque at low RPM, but the lower torque at higher RPM. The crossover happens roughly at 3000-3500 RPM. Edit - I added data for the Advanced DC 9" motor for comparison purposes:

Most people are accustomed to thinking of motor performance in horsepower, so here is the same data recalucated for HP:

I think this chart illustrates well why the AC55 is suitable for truck / SUV applications, whereas the AC24 is much better for smaller, sporty cars. This higher torque / HP is going to be especially important for the Jeep, since its curb weight is 50% higher than the Porsche, and its battery weight will similarly be 50% higher.

Time to look into 4-wheel disc brakes...