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Old 12-04-2009, 11:13 AM   #7 (permalink)
Ford Escort 2.0
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Join Date: Feb 2008
Location: Alameda, CA
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Electricar - '89 Ford Escort LX Hatchback
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Congratulations on the battery find!

Here are a few basic thoughts on EV performance to keep in mind as you gather parts for your EV build:

1. Acceleration = Amps. The higher amperage a controller and motor, etc. can handle, the quicker the vehicle will accelerate. A 500 amp controller will accelerate faster than a 300 amp controller.

Series motors use fewer amps as they accelerate. As an example, my motor uses about 400 amps (controller limit) for the first couple of seconds during acceleration, but tapers off to about 130 amps at top speed.

2. Speed = Voltage. In general, series DC motors (kind most commonly used in EV conversions) will spin faster with higher voltages. Your golf cart might go 20 MPH at 36 volts, and perhaps 25 at 48 volts.

One parameter of series motors is their RPM/Volt number. Some series motors will turn faster at a given voltage (high speed motors) while others will turn slower (high torque motors).

3. Range = Battery Volume. More/larger batteries (more total amp/hours) = more range, regardless of chemistry. If your golf cart had three motorcycle batteries (36 volts) it would probably work, but only for a short distance. With three 12v car starting batteries, it might go a few miles. With three 8D truck batteries, it might go ten miles. (of course, true deep-cycle golf cart batteries are normally used for max range and battery life).

Biggest problem here is that more batteries = more weight, which takes away from acceleration and speed, and in some cases the number of passengers you can carry in a vehicle... Lithium batteries certainly address these issues.

Here is a link to what your lithium batteries could look like...
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