Unresponsive MP

[mantares]

 

I have two MP's, one I purchased a couple of months ago and one I just received (they have been installed on a 3-wheel solar powered cart running at 24 volts; the two side 20" bicycle wheels have the motors installed). The first motor is working flawlessly and I am extremely pleased with its performace. The second motor is not working at all. Symptoms: 1) no initial beep; 2) no output from the 8-pin connector, either the 24V line, or the 5V line, and of course, 3) no movement. Both motors are running from the same 24V supply. The throttle (a GM thumb version) has its 5 volt source from the good motor and the white wire throttle control goes to both motor throttle inputs. The good motor throttle control is working OK, as is its brake control. The second motor 5V output is not connected. All grounds are connected together. As a side comment I'm an electrical engineer so feel competent that the motors are wired correctly. I checked that the 24V connector to the motor is supplying 24V but have not determined that 24V is actually getting to the motor (bad connector?). I haven't tried to open the case.

Looking for troubleshooting hints...

Thanks,
Michael Antares

[Leslie]

Cab you test the resistance of both wires leading to the Magic Pie from the battery when it is unpluged.

Switch through the common settings and see if you get any resistance at all.  0 resistance is a dead short.  And some resistance shows at least there is a load.

No reaction from the ohm meter shows there is a bad connection,

What you should see is it go from 0 resistance (dead short) or to close to it, and the ohms should increase as the ohm meter charges the main caps.  This is why you get a spark when you join the cable.

I do not know the input off resistance of the MP controller but it should have some.

Let us know how you go.

[mantares]

Thanks for the input, I was thinking of doing just that (ohming the MP input power). I'll let you know the results...

[Bikemad]

My Pie stabilises at approx 6,300 ohms if it helps.

Alan
 

[Leslie]

My Pie stabilises at approx 6,300 ohms if it helps.

Alan
 

Allan what is the MP's current draw when switched on and not moving?
 

[Bikemad]

Alan what is the MP's current draw when switched on and not moving?

Mine reads ~60mA @29.5V

[Leslie]

Thanks we can ask if this is the same as Mantares bike.

The current should be very close on most voltages.  My ecrazy controller I get 50ma at 60v.



If there are any odd readings like 2 ma or 500ma, such readings can tell us a lot about if the device is in normal function.

[mantares]

I did a lot of checking today and this is the result:

The problem is an intermittent. I haven't found which one or where as yet. I assume, since when it's bad there is no 24V or 5V output, that the intermittent wire is one of the 24V supply wires. However when the motor is OK, deliberately moving the cable doesn't obviously make it quit. I did reduce the diameter of the 24V connector sockets by squeezing the contact but that didn't cure the problem. When it's working (which it is right now), the overall performance is everything I could wish for. Throttling both motors from the thumb throttle works well--I don't see any tendency for one motor to run significantly faster than the other. The brake pull-down is awesome, in fact I wish it could be proportional; far better than the rim clamp brakes I previously had. In my situation, going down a steep mountain road while sitting on the cart, experiencing a loss of braking could be fatal.

Michael Antares
located in Northern California on the Russian River.