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Old 11-27-2007, 06:46 PM   #473 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 20,789

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

MPGiata - '90 Mazda Miata
Last 3: 51.27 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 58.31 mpg (US)
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10-15-2007, 05:33 Pm

Today... skooled by the EV masters was I.

I asked a question on the EVDL about driving technique. I was pretty sure about the best efficiency methods, but not so much on how to make it accelerate faster.

Someone sent me an excellent summary of efficient vs. aggressive dc/serial motor EV technique. This was part of documentation that came with his old Jet Electrica (commercial Ford Escort conversion).

Result of skooling: easily lopped 1/3 off my 0-30 mph time

It's enough of a difference that now I'd consider driving it on some of the grown-up roads that I thought were off-limits.

The trick in a nutshell (pretty obvious when you think of it): mat it, and short shift. DC serial motors make the most torque at low RPM being fed lots of amps, so max out the current limit on the controller, watch the ammeter and upshift as soon as battery current falls off the limit as a result of motor RPM rising.

My previous attempt at 0-30 (before the car was legal) was done in 1st & 2nd. I did it this evening in 1st-4th and the difference was obvious. Whee!!

Quote:
Originally Posted by 2ton
So all you need now is a new gearbox.

1st 10:1 for the first 2 meters...
2nd 3:1
3rd direct
4th 0.5:1

good luck finding it

Very interesting...
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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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