Magic Pie 4 of mysterious misery

[Tremor8.0]

I have installed a new mp4 on to my trike but am having a strange problem. 


OK so the lights are on on the throttle, the battery is at full charge and I test it in garage, Yay success, its working.  Then I bring it outside did one final test with the wheel up and then I sit down and nothing... huh?  I thought it has to be a loose wire somewhere, but the lights are still on on the throttle.  So I double, tripple check all the connections and swear a bit, but no go.... Then randomly its working again.  So I zoom up the street with a smile, turn around, and no motor again(throttle lights on).. scratch head ...  The motor was cold, no way it could have overheated, so more checking wires and swearing.  Then magically it starts working again?


It seems to shut down for about 5 mins.  Could it be getting a false temperature reading?


Other info:
-I disconnected one of the brake levers, only using one, as front brakes are hydraulic.
-When I fiddled with the 2 button switch the horn button sparked at the end of the wires(where horn would connect), so I disconnected it as well.  So just 1 brake and 1 throttle.

Ideas anyone?

[Bikemad]

Hi andto the forum.

You need to properly insulate all the unterminated wires (four on the control harness and four on the motor harness) to ensure that none of the individual wires can touch each other.

If these wire are allowed to touch (like yours obviously have) not only could it prevent the motor from running, but it can also melt the wiring inside the harness in seconds if either the light switch or horn button is pressed while the lighting/horn feed wires are touching either of the two ground wires! 

Alan
 

[Tremor8.0]

Thank you Alan

The spark I spoke about was at very tiny and occurred at the very end of the light/ horn wire, which was unmodified and factory shielded.  I do not believe it could have melted  the wiring harness, but mentioned it just in case.  I have now separated the wires and individually shielded them.  Still having problems.

If this problem is truly caused by the wiring harness shouldn't the wires be better shielded from the factory, as all I did was touch the button?

Heres my problem: The motor works great for a minute or less and then shuts down for about five minutes?  What could cause this?

Ian

[Bikemad]

If this problem is truly caused by the wiring harness shouldn't the wires be better shielded from the factory, as all I did was touch the button?

Hi Ian, I totally agree with you, those wires should not be left simply cut off and uninsulated.
At one time GM would put a single piece of heat-shrink tubing over the end of the cable, but this did not prevent the insulation on the wires from shrinking inside the heat shrink tube and exposing the ends of the individual copper wires.

If the Red lighting feed wire touches against the Black ground wire it will cause a direct short circuit as soon as the lighting switch is pressed. The tiny wires are only capable of carrying low current, so they will melt like a slow acting fuse when shorted directly across the battery.
Please don't try placing thin wires directly across battery terminals as you could end up with tiny grooves burned into your fingers and thumbs!!

Anyway, the fact that yours is still working, albeit intermittently, could be a good sign.

What battery are you using (voltage and type)?

Do you know what voltage the controller is set to?

When it cuts out, are all three LEDs still showing on the throttle, or do they start to go out when you operate the throttle?

When it cuts out, does the regenerative braking automatically cut in? (The regen tends to make it much harder to pedal above 6 mph when it cuts in)

I must admit that it does sound as though something could be overheating and breaking down until it cools off again, but I'm just not sure which part could cause this problem.

Intermittent faults are often caused by poor contacts on connectors and switches, so recheck that all the connectors are pushed together correctly and try wriggling the keyswitch when the fault occurs to see if it makes any difference.

One other suggestion, if your charger has a switch to select the correct input voltage, make sure it is in the correct position (110V or 220V) to suit your mains voltage:



If you have a 110V mains supply and the charger is set to 220V (like the one above) your battery will need to be recharged with the voltage selector switch in the correct position.
You can use the tip of a pen to slide the switch to the correct position 

Alan
 

[Tremor8.0]

Thanks Alan, my battery is a Headway 48V, LiFePO4, 10ah, 10C, 38120s cells, rated at 100A max cont discharge.  I installed a second charge indicator directly at the battery which shows a full charge.  It has to be charging correctly.

I am not sure what the voltage on the controller is set for.  My second problem is getting connected to the controller, which hasnt gone well so far.  I finally got the driver, and correct com, but am now getting a "data packet length error"?

The LEDs on the throttle still indicate full charge when the motor cuts out, and the regen brake stops completely as well.

I have checked all connections again and the only possible problem I can see is the anderson connectors Ive used at the battery don't seem to click together as they should.  I had them held together with zip ties to be safe but Ill see if I can fix them or change to new connectors.  The less likely problems I could see are with the controller or throttle.

If the battery connectors were to short for a milisec, as in bumped, could they cause these symptoms? 
 
Ian

[Bikemad]

Hi Ian,

If you are using a 48V battery then the voltage setting in the controller is unlikely to be causing your problem unless the "Undervoltage protection value (V)" has been substantially increased, but as you have not been able to connect it is very unlikely that this value will have been changed.

An intermittent battery connection should only cause intermittent cutting out and the motor would work again as soon as a good connection was made. I would expect the LED battery lights to go out if the battery connection was bad enough to cut the power, but apparently with some BMS problems it is sometimes possible to have enough current for the LEDs to light up, but not enough to actually run the motor.

With a minimum of 100 Amp discharge (unless you have a BMS which limits it) shorting the battery contacts for any length of time would generate a great deal of heat in the battery wires, but a momentary short would probably produce a big spark that is often accompanied by a loud bang.

If you have a low power BMS and it's continuous current output is lower than the current being drawn by the motor, then it's possible that the BMS is being overloaded and is cutting out. This might account for the return of power after it has cooled down again.

Alan
 

[Tremor8.0]

I don't think there has been a short at the battery terminals as there is no sign of an arc, nor have I noticed a spark or bang.  The bms is rated at 50-100A so it should not be the problem.  The battery shows a full charge immediately after a shutdown as does the throttle indicator.  I have also felt the battery, terminals, wires and motor for any signs of heat but everything seems cool to the touch.

I have not timed the shutdown but it seems to be around 5 mins which I thought I had read is the amount of time the controller will shut down for if the motor overheats.  Perhaps it is getting a false temp reading somehow.

Is there a list of controller errors which will cause a controller shut down.  Troubleshooting would be easier with a list of problems to eliminate.

Should I be opening the hub up?  Im not sure I would know what to look for, unless there are loose wires or something.

I cant even get to the end of the street and back.  This thing is taunting me