Album:2005:06-10 Electric-Vehicle

I started building an electric vehicle for Burning Man.

I haven't finished it yet, but here's some of the design so far.

Required components:

  • Motor(s): 2 EV Warrior motors.
  • Speed controller: Curtis 1204-015 275A 24-36V Golf Cart controller
  • Batteries: 6 of 12V 9Ah batteries (from emergency lights - $7 ea)
  • Charger: 8A 24V wheelchair battery charger
  • Throttle: homemade
  • Chassis: homemade (in progress)
The charger
had a 3 pin Microphone-style connector, so I bought a mike cable, chopped off the connector and attached it to some power wires for the battery harness. I found some rubber hose that the wires barely fit in and used that for protection/insulation.
Beginning of battery harness Final battery harness
with connectors laid out, showing red side still minus insulation
The harness and connector.
Battery pack hooked up. Attached to motor
for a test runner (sans speed controller)
Motor kicks in,
bam! [Video, 2.9M]
Throttle potentiometer.
I need 0-5k, so I use a portion of the range on this 25k pot.
with "machined" hole. :)
Batteries in box
showing speed controller on side and clear cover. I have two extra batteries, I figure if I run out of power I can connect those two up and limp home.
I weld a small box
to mount the potentiometer in.
I attach a plate
to the potentiometer.
And add throttle stops
to limit the pot from 0-5k.
I "machine"
some power connectors from sheet metal using a drill, a clamp and lots of solder.
The power connectors
attached to the speed controller using thumb screws.

Here are some preliminary estimations for performance.

To run for one hour @ 24V and 480W (20A) I need 20Ah of batteries. But the quoted Ah is for 10 hours, we probably need 25Ah or 30 or so. To be safe, I got 27Ah.

Charging in 8 hours takes 2-3A (60W) charger. I have an 8A charger, and plenty of 24V charge on my bus as well.

I bought a Curtis 1204-015 (275A) controller. The model 015 allows for double braking current (which doesn't matter to me) and has no HPD. I didn't pick this specific model, I just found it on ebay. Anyways, this can handle a few kilowatts of power, so it's more than plenty.

The motors are both from EV Warrior bikes. They were rated at 12V, but many run them at 24V with no problem:
12V, 2210 rpm, .378HP, no load 2.6A, stall 99.2A, stall torque 691 oz-in
24V, 4480 rpm, 1.55HP, no load 2.6A, stall 198A, stall torque 1400 oz-in

Allegedly I can get 3HP out of both of them, though I can't quite reach a combined stall current of almost 400A, but that wouldn't be good for the motor anyways. I'm told it's more like .75HP each at 24V and 2210RPM. We'll see what the truth is.

I'm hoping to get around 12-30MPH and an hour of run time before charge. That seems entirely possible considering how massive my setup is compared to little electric scooters with smaller batteries/motors.

Powered by album tool from MarginalHacks by Dave on Sat Oct 28 04:20:36 2006