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| Vehicle Name: | | Electro-Willys |
| Builder: | | m38mike |
| Started: | | 2008-09-10 |
| Finished: | | 2010-05-01 |
| Build Duration: | | 598 days |
| Build Hours: | | 500 |
| % Complete: | | 95% |
| Added: | | 2009-01-25 |
| Last Updated: | | 2010-07-08 |
| Main Build Thread |
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| Donor Vehicle: | | 1952 Jeep M38 |
| Donor Cost: | | $2,000 |
| Conversion Cost: | | $8,000 |
| Total Cost: | | $10,000 |
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| - Performance and Range - |
| Max Power: | | 23 kW |
| Top Speed: | | 70 mph |
| Acceleration: | | fast! |
| Final Weight: | | 3200 lbs |
| Range at 30: | | 20 miles |
| Range at 55: | | 15 miles |
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| - Batteries / Charging - |
| Battery Type: | | Flooded Lead Acid |
| Battery Manufacturer: | | Deka |
| Battery Configuration: | | 18 - GC8V batteries in series. Eight in one box up front, 10 in the back. |
| Battery Pack Voltage: | | 144v |
| Charger: | | Zivan PFC1500 |
| Charge Time: | | 6-7 hours at full draw |
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| - Drivetrain - |
| Controller: | | Logisystem 144v 1000a |
| Motor: | | WarP11 |
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| - Accessories / Other - |
| DC-DC Converter: | | none |
| Air Conditioning: | | 2-25 AC (2 doors off at 25 mph) |
| Power Steering: | | Armstrong |
| Brakes: | | 9 inch stock drum brakes with an old Navy anchor as backup |
| Tires: | | Coker 7.00x16 NDT Military |
| Other Notes: | | My objectives are: 1. Create a usable commuter EV from a Willys Jeep. 2. Get a 40-50 mile range daily. 3. Keep the jeep looking like a restored military vehicle. 4. Learn a lot. 5. Enjoy showing it to anyone interested. 6. Save money by not buying liquid fuel.
The conversion shop has put 4 different motors in it so far. Two because they messed up the motors, and the last one because they didn't design the conversion efficiently.
We are having problems getting settings in the Kelly controller to work well with the Warp11 motor. Part of the problem may be voltage sag or Peukert's in the GC8V batteries. After about 10 miles the batteries simply fade away. If I let them sit for a few minutes I get some of the power back. I've been doing some calculating on power requirements. Here are my equations.
Power in Watts = ((Mass in kg) (9.8m/s²) (Velocity in m/s) (Rolling Resistance)) + ((0.6465) (Coefficient of Drag) (Area in m²) (Velocity^3))
Assume vehicle is 3500 lbs and driven at 55 mph for one hour (two 30 minute trips).
P=(1590)(9.8)(25.85)(.015)+(0.6465)(0.46)(2.32)(25.85)^3
P=(1590)(9.8)(25.85)(.015)+(0.6465)(0.46)(2.32)(17273)
P=6041 W (rolling resistance)+11917 W (aerodynamic drag)
*P=17958 W = 18kW*
** /using the same assumptions at 45mph, P = 10.3kW, barely over half as much power.
This calculation estimates power (power = energy per unit time: 1 W = 1 Joule / second). To calculate energy multiply power by time.
If 55mph in a 3500 lb jeep takes 18kW, then for one hour, it would take 18 kW hr.
At 9 cents per kw-hr: $0.09 x 18kW-hrs = $1.62 per day to operate this vehicle
18kW/144V = 125A @ 55mph to maintain speed on flat ground
10.3kW/144V = 71A @ 45mph
With 8V batteries, the total amount of amps needed in the pack = 18kW/8V = 2250 Amps. This doesn't account for the efficiency of the controller and motor, but that should be around 80%.
So 2250/.8 = 2812 Amps worth of batteries are needed to accommodate the controller/motor loss.
I only want to run my batteries down to about 70% DoD so 2812/.7 = 4017 = ~4000. To get this with my 18 batteries would require each battery to provide 223 amps.
For the batteries I have, the Peukert’s exponent is 1.2 according to Deka. That means that instead of only 223 amps per battery I need 223(1.2) = 268 amps per battery.
Taking the batteries to 80% DoD will require 2812/.8 = 3515. 3515/18 = 195 amps per battery. With Peukert’s exponent the final requirement is 195(1.2) = 235 amps per battery.
Currently my batteries have a 20 hour amp rating of 135. Looks like I might not get to work and back again with my existing pack. |
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| - Stats - |
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