Drive ratio BMC 1500

[topever]

Hi guys,
quick question, maybe someone can answer. I've got a BMC 1500 watt motor turning a 10 tooth sprocket to a 48 tooth sprocket driving an axle with 10 inch tall tires.
The motor/ controller shuts down after 1 second of throttle. This is up on blocks, no load. 48 volt 12ah sla batts. Edward Lyen is helping me try to figure out why its cutting out. Am too high on my ratio? Should I run a jackshaft with another set of 10 to 48 tooth sprockets? That would put me at about a 9 to 1 ratio, right? I have no idea if that is where its supposed to be. This is my first build. It's a pusher trailer. Edward just sent me a large paragraph about something I don't have a clue about. I can tear the engine out of your car and rebuild it with more horsepower, and weld together a roll cage for you, but I don't have a clue about electronics.
Flame if you want but I'm not going to go to school and learn all this. Thats what freinds are for. I can upgrade to an 18 fet controller, and from what Ed is saying, it might be a good idea. I'm running his 12 fet now. If you guys think a jackshaft is the answer, I can whip that out no problem. I just want to go flying down the street and watch people freak when they see I'm not pedaling. (motor and batts are hidden). Thanks for listening. I'm a noob so be gentle.

 

[DAND214]

Have you tried running the motor without the chain? See if it runs longer, if so then it's the drag or the gear ratio is too high. If it doesn't run any longer it's the motor/controller problem. I wouldn't think it should shut down without a load on the wheels.

Does it restart right up again after stopping? Motor or controller getting hot?

Try that and see if it helps.

Dan

 

[topever]

Yes it will start up again immediatly after releasing throttle and starting again. But only for 1 second. Edward has bench tested it with nothing on it and he says it runs fine. A wierd noise at full throttle though. motor and controller never got hot. There can't be that much drag just running a chain and two ten inch tires in the air. I can turn that with my fingers. This BMC 1500 watt motor is supposed to be a beast from what I've read. Could there be a problem with phasing perhaps?

 

[DAND214]

I agree on the next to nothing drag in the air. So it's got to be the motor if the controller has been checked.

Maybe the throttle but not likely.

Have you tried other phase combos?

Maybe it's just a shorted motor.

Dan

 

[topever]

I need to bump this cause I still don't have an answer. Does anybody have any insight on these 1500 watt bmc motors? I believe the problem is in the motor but who has the expertise on this thing? I don't know where to turn for help. I'd hate to see this project die because of this. Surely there's an electronic guru that knows these motors. I got it from tim, associated with superkids, but he does'nt answer his phone. So i'm on my own here. Edward is swamped but he's trying to help. Anybody got a suggestion? Thanks.

 

[gogo]

Tell us more about your batteries. Have you measured the voltage drop at the point of controller cut-out?

 

[mdan]

its your phase wires, I had the same situation, have the same motor too. Ed sent me the phase wire schematics for his controller etc. once the right combo was set, the motor was good to go. Ask him to send you his wiring schematics for the motor. He runs one or two of the same exact motors on his bikes.

good luck,
Mike