Dennis Miles wrote:
Lee Hart, I have great respect for you and your opinion. I would admonish anyone not to go and try using a motor controller for a battery charger without ascertaining the exact design parameters it is capable of. Every model is usually different and some are capable of battery charging right off of the shelf, and others will require current limiting, to prevent excessive current flow, or other circuit enhancements. Technical Expertise, is why some can modify or repurpose equipment and others who haven't the knowledge can not...
You're right, Dennis. You don't want to fool with this stuff unless you know what you're doing. One mistake, and you can blow an expensive or motor controller!
That said... Figure out what current your resistive load would draw if you connected it straight to the battery. If that's less than your motor controller's rated current, it's pretty much a safe bet that you won't hurt anything powering that resistor with the motor controller. The motor controller will just work like a giant rheostat. It lets you 'throttle' power to the resistor just like it would do for a motor.
At worst, a microcomputer in the controller might shut down and say, "Hey, that ain't no motor! I ain't gonna power it!"
As for using a motor controller as a battery charger: That is a much trickier proposition. A battery has very low resistance, and can deliver awesome peak currents! Few motor controllers are going to like powering a battery directly. To do it, they would need a substantial output inductor. The GE EV-1 happens to have such an inductor; but many controllers won't!
-- Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius, and a lot of courage, to move in the opposite direction. -- Albert Einstein -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
