I think the guy meant energy usage efficiency, not motor efficiency. Drawing less amps means the motor and controller doesn't get as hot, and the batteries aren't depleted as quickly, so range is increased. This implies overall efficiency of the SYSTEM (as installed) is increased. I'm trying to figure out what's implied as happening, not taking him literally. On May 3, 2007 andrew hay wrote: > " From: Wrambler242@xxxxxxxxxxx > " > " I stumbled on the website that the guy has who built the 4X4 XJ EV. Url is at work. Google should be able to find it, try EV Jeep or somethignt o that effect. > " Anyway, he says that electric DC motors get the best "economy" by running at their rated rpm. > > i think he's talking through his hat. electric motor -efficiency- is > not dependent on speed. > > it may be true of -his- installation, but he's made choices limiting > his flexibility. maybe even some choices he's not aware of, imho. > > " If you think about it lugging an electric causes a need to increase the amperage to maintain rpm. > > you mean overloading it, demanding more hp? that takes more current > at any speed. > > " So a 4 speed non OD trans would in fact be a fairly good tool to allow one to be able to keep the motor at the "sweet" spot. > > electric motors [with electronic controllers] don't have a sweet spot, > unlike internal combustion engines. they usually have constant torque > [within thermal limits] up to a certain speed, then constant hp above > that. if he's not getting that, he's not getting everything he could > out of his motor. > ________________________________________________________________________ > Andrew Hay the genius nature > internet rambler is to see what all have seen > adh@xxxxxxxxxxxxxxxxx and think what none thought > _______________________________________________ > Amc-list mailing list > Amc-list@xxxxxxxxxxxx > http://www.amc-list.com/mailman/listinfo/amc-list ============================================================= Posted by wixList Archiver -- http://www.amxfiles.com/wixlist _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list