Shorted Wires

[Evets]

Hi all, I'm new and have just had my first failure. Bought a 750 watt Bafang geared hub kit for my fat bike from Eunorau, but after 200 km it stopped working and displayed error 03 which the manual says is hall sensor abnormality. Opened up triangle bag to see controller and discovered that the 3 motor wires are fused together where the connector insulation has melted. Separated them and tried to turn battery on again, but it starts the motor turning briefly and shuts off before I can turn on display. Eunorau will not honor their 3 year warranty, and tells me to order a new controller which I've done, but I wonder if anybody else has had this problem. I hope the motor is not damaged.

 

[Ann M.]

@Evets, sorry to hear about your issue on the kit; I'm moving your post to the relevant Bafang forum and would like to invite @Hangzhou BTN ebike, which is Eunorau, to respond. There are too many details missing, including anything about your battery, riding conditions, item the kit was insalled on, etc. to understand what may have happened so we can only speculate. The Introductions & Bike Garage is not the space for complaints.

 

[Evets]

Oh, so sorry to post in the wrong place. Thanks for providing the email address for BTN.

 

[Evets]

Battery is a 48-52 V dolphin pack bought at same time as kit which worked great for 200 km on same daily route of 12 miles with steep hills at the end of the run. Was able to pedal along with motor on full with twist throttle up these hills at 12-16 kph for over two months no problems and only used 80% or so of battery which was fully charged. I suspect that the translucent green insulation sleeves are the problem, as the silicone connector covers are unscathed as seen in photo. The wires were indeed fused together with bare metal showing on all after I pried them apart. All other wires & connectors look fine. This kit is installed on a Gravity fat bike from BikesDirect.

 

[harryS]

When you get the new controller, I suggest you not put it back inside the triangle bag. Mounting on the frame might have given enough cooling airflow to not melt the sleeves.

I would be optimistic about the motor still working. What most likely happened is that you blew up the power transistors in the controller when the wires touched.

 

[Evets]

Thanks for the suggestion Harry, I will absolutely mount it outside the bag and also use heat shrunk covers in place of the stock insulation.

 

[Evets]

Received the new controller today and hooked all the wires up where they're supposed to go, then installed the battery, turned on the power button and was glad to see the display come on as it should. As soon as I twisted the throttle, the display "info 03" came on again, so I have disconnected the battery and am assuming there's a problem with the motor now. Originally thought the problem had to do with poor insulation causing the connectors to short, but now I'm wondering if the hills I had been climbing were just too much for the motor. After removing the melted insulation I see that that all three connectors themselves were greatly heat discolored, yet only two had melted enough to cause a short. Yes, I have e-mailed BTN / Eunorau support, but no reply yet. I know some people have had to replace the three hall sensors inside the motor, so wonder if anybody knows anything about that.

 

[harryS]

The connector for your Hall sensors is a white rectangular plug with 5 or six wires going to it? Are the wire colors on each side matching? Are all the pins seated on both sides of the connector? Sometimes they pop out.

If two phase wires got that hot, it's possible they also got hot enough inside the cable to melt thru to the oth(Link Removed - No Longer Exists)er wires, but it still seems more likely that the bullets heated up first simply because of contact resistance. Unlikely to affect the Halls, unless you're very unlucky.

Does the motor turn backward easily? If the phases were shorted to each other inside the cable, they would act like a regen brake and prevent a geared motor from turning backwards.

If you have a voltmeter, it's possible to test the Hall sensors in place. The connector is open on the motor side and you can put the probe on the contacts. Red and black are power. You should see about 5 volts from red to black. Then test the blue, yellow, and green wires, using black for the negative lead. If the sensor is working, the voltage will flip between 5V and 0V as you spin the wheel backwards.

 

[rich c]

I have a dead Bafang 350 watt motor with the same 03 Info on a Sondors. I plugged the motor into another bike, same thing. So knew it was the motor. Sent if off and he told me cold solder joints on the hall sensors. Shipped it back and it worked for 10 miles. Died again. They are promising a replacement motor, but nothing after a few weeks. 03 is either wiring problem or hall sensors, that's the only options.

 

[Evets]

The connector for your Hall sensors is a white rectangular plug with 5 or six wires going to it? Are the wire colors on each side matching? Are all the pins seated on both sides of the connector? Sometimes they pop out.

If two phase wires got that hot, it's possible they also got hot enough inside the cable to melt thru to the oth(Link Removed - No Longer Exists)er wires, but it still seems more likely that the bullets heated up first simply because of contact resistance. Unlikely to affect the Halls, unless you're very unlucky.

Does the motor turn backward easily? If the phases were shorted to each other inside the cable, they would act like a regen brake and prevent a geared motor from turning backwards.

If you have a voltmeter, it's possible to test the Hall sensors in place. The connector is open on the motor side and you can put the probe on the contacts. Red and black are power. You should see about 5 volts from red to black. Then test the blue, yellow, and green wires, using black for the negative lead. If the sensor is working, the voltage will flip between 5V and 0V as you spin the wheel backwards.

Hi Harry, Thanks for replying. Yes the motor spins backwards fine. I have visually checked the connector for the hall sensors and also used a small screwdriver to push the individual pins in , but the display still shoots out the "info 03" code as soon as I touch the throttle. There is no evidence of any of the wire insulation having melted anywhere. The motor does start briefly just before the code. At least the new controller is allowing me to power up and turn on the display. I will try your suggestion for testing with a voltmeter later and report back later. The best news is that owner of the company has contacted me thanks to Ann e-mailing him directly. He has asked for a video of all my connections, so I'm off to do that now.
I'm very grateful for the support from you and Ann.

 

[Evets]

Dear harryS, I tested the leads as you suggested, but got 4-5 volts on red, blue, green & yellow BEFORE I even spun the whee backwards. Spinning the wheel did not appear to change the reading. I did this with the battery on and the display on as well. Sent a video of my connections & display error to Eunorau/BTN, but they only suggested I disconnect the brake wires which changed nothing. No problem powering up battery or display, but as soon as I turn on throttle the motor starts to turn then stops and display reads "03 info".
I do appreciate your interest and suggestions, as the company will no longer reply to me.

 

[harryS]

Sorry. If you did it right, the test indicates the the three Hall sensors are not working. You will get the 5volts before spinning the wheel, with the Hall connector attached. As it spins, each lead should drop down toward 0V several times per revolution. You have to turn it backwards because it's a geared motor, and it freewheels spinning forward due to an internal clutch. You do need to turn the wheel slowly, since if you use a digital meter, it doesn't display fast enough,

These inexpensive testers from China will tell you the same thing. You plug in the appropriate connector for the motor coil or Hall sensors and the LED's flash when you spin the wheel. Takes too long to ship, but well worth the $15,
https://www.ebay.com/itm/24V-36V-48....l1313.TR1.TRC0.A0.H0.Xebike+tester.TRS0.TSS0

Some people feel they can replace the sensors. I've never opened a motor or wish to do so.

 

[Evets]

Sorry. If you did it right, the test indicates the the three Hall sensors are not working. You will get the 5volts before spinning the wheel, with the Hall connector attached. As it spins, each lead should drop down toward 0V several times per revolution. You have to turn it backwards because it's a geared motor, and it freewheels spinning forward due to an internal clutch. You do need to turn the wheel slowly, since if you use a digital meter, it doesn't display fast enough,

These inexpensive testers from China will tell you the same thing. You plug in the appropriate connector for the motor coil or Hall sensors and the LED's flash when you spin the wheel. Takes too long to ship, but well worth the $15,
https://www.ebay.com/itm/24V-36V-48V-60V-Electro-Car-E-bike-Scooter-Brushless-Motor-Controller-Tester/132689335695?hash=item1ee4e6958f:g:RAwAAOSwvrxbRdXn&_sacat=0&_nkw=ebike+tester&_from=R40&rt=nc&_trksid=p2380057.m570.l1313.TR1.TRC0.A0.H0.Xebike+tester.TRS0.TSS0

Some people feel they can replace the sensors. I've never opened a motor or wish to do so.

Oh, I don't feel comfortable opening up that motor either. Now trying to get Amazon & Discover to help, as the seller is not even replying now. Thank you so much for helping me pinpoint the problem. Very unhappy with Eunorau/BTN support.