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Old 11-27-2007, 11:18 AM   #261 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,515

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 52.48 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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Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
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