Battery Vehicle Society

I have stumbled upon a good site for general interest "EVAlbum" which has pics and write up's on many ev's, both production and conversions. One thing I don't understand tho, with the same motor, controller, voltage and vehicle size all those guys are going much faster and farther than I. Is this the same situation that causes the other guys to catch more and bigger fish than I do?
tommyt

Actualy that site has been around quite a long time and has over 1200 EVs registered on it including some of our member's

Not sure what controller and power plant you have but I can assure you there's a vast variety of them there. Where in the world are you located ? I'm guessing you're in the USA and it may be that you are referring to NEVs which in the USA are restricted to I think 15mph top speed by law. Here in the UK we don't have this law as we don't have gated communities which they were intended for.

Qdos
Yes, I am in the US, specifically southern Indiana. Not sure what an nev is, but my pickup truck, an'82 Dodge ram 50 (Mitsubishi) is registered just as any other and subject to the same rules.
It has a D&D motor (ES-15A-6), an Alltrax controller (AXE-7245) and 12 Group 27 12V batteries. I use a V-belt drive to the rear end (no gearbox) with an overall ratio of 8.36:1 and 195-14 tires.
Somehow the motor seems to be limited to abt 3500 rpm. This limit appears to controlled by amperage; whether it is imposed by the motor or controller is unclear. At 34 mph, with the notgas pedal to the floor, I am seeing only 90A when the system is capable of (and at stall will deliver) 400A.
Most of my life has been spent in utter confusion and I don't see that changing soon.
tommyt

NEV = Neighborhood electric vehicle:

http://en.wikipedia.org/wiki/NEV

And the reason you only get 90A at 34mph is that the motor is acting as a generator (simultaneously!) and producing "back EMF". This is a voltage that opposes the battery voltage, and hence reduces the current that the motor can draw. All DC motors do this, and hence, EVs will have a stall current that's much higher than the running current.

Ana;
The back EMF makes sense - explains what I am seeing. Is this proportional to voltage or amperage or both? If both, in what proportions? Motor rpm probably also plays a part.
tommyt

I think back-EMF is proportional to motor RPM, but will also be affected by the field current, in the case of a non-permanent-magnet motor. Back-EMF is, of course, what we utilise when we implement regenerative braking.