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Old 11-27-2007, 12:18 PM   #261 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

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90 day: 52.8 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 73.57 mpg (US)

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01-21-2007, 12:08 Pm

The forklift pot is interesting. With a jumper wire (short) connected between the 2 ends of the resistor, the 0-23k pot acts as a 0-6-0 k pot - meaning resistance is highest with the wiper centered between the 2 ends and drops as you turn it either way from center.

The problem with getting just any 0-5k pot is they're usually about 300 ish degrees of rotation. But the arm on the potbox only moves about 70 degrees.

I suppose this is why the strange, jumpered, 23k forklift pot setup works. When set up that way, the resistance goes from 6k-0k within about 50 degrees of rotation (which is what we want).

Anyway, finding another pot is all moot, since I figured out how to make the forklift potbox work with the Curtis.

No need to harvest the pot from something else!

Controller: we're going to go with the Curtis to start. But will probably swap in the forklift's EV-1 controller at a later date, just to compare.

The EV-1 has a higher current limit (around 400A, compared to 275A for the Curtis), but it has no filter capacitors on the input side, so it'll hammer the batteries and reduce range as a result (input capacitance wasn't a concern in the forklift application because its 3000 lbs of lead acid effectively gave it enough capacitance). This is all stuff I'm parroting from the EVDL. I don't have a thorough understanding of it.

All I know is that people who use EV-1's say their range is reduced by 20-50% compared to a modern controller (e.g. the Curtis) with input side capacitors.

Since our goal is most range (spirited performance be damned), the Curtis is the way to go.

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