In dire need of help

I have tried searching for my problem, but didnt have any luck finding any answers.

I have a li-ion nmc 48v battery and a rear hub kit 48v 1000w

I was riding last night and my chain slipped. As I was putting it back on, the bike fell and stripped out the wires going into the rear hub. I got the chain back on, but noticed that there seems to be a lot of resistance in the wheel, and the throttle shuts off after a few seconds. If I release the throttle and hit it again, it goes for another few seconds.

I took the hub apart, and wired everything back together, but it is still doing the same thing. I dont know what to check now. Hoping someone who has experienced this can shine some light on what to do. The battery was in a plastic box with a lot of bubble wrap. I am getting 54v from the battery, and its seems to charge just fine.


I did not see any other spots in the wire when I had the hub apart. Thank you for any suggestions. This is my only transportation.

This is a common problem, and the solution is the same each time, usually.

If it doesnt' have the resistance when the controller is not plugged into the motor, then the controller is damaged, probably FETs shorted that need to be replaced.

If it does have the resistance when controller is not plugged into the motor, then the motor wires are shorted together in the harness, and you need to re-insulate or replace them.

Hey amberwolf!

I should have been more clear on the resistance.

When i spin the wheel by hand, there is no resistance. What i am referring to, is when I have the rear wheel off the ground, and hit the throttle, it is making a weird noise that sounds like it is being bound up, but there is nothing coming into contact with the rim or tire.

So if there is no resistance when spinning by hand then the controller is probably fine and the phase wires (thick ones) are probably fine. Instead this sounds to me like a hall sensor problem since it only occurs under power. There's a chance one of those little hall wires got damaged and it's just hard to find the spot since they are so small. I recommend following each one into the motor and checking carefully.

Ok, thats what I was planning on doing. Theres got to be a spot on a wire somewhere. It works fine, just kills the throttle. not like other problems where everything would shut off. so that made me wonder if it was just a bad spot in the wire.

the fall was not hard, it was stationary, and I grabbed it close to the ground. I have the battery pretty protected with the same bubble wrap that it was shipped with

I will take it apart again and trace all of the small wires first. Thank you guys.

Took it back apart. Could not find any other trouble areas on the wires. I dont have a tool to take the freewheel off, to get the other side of the hub off.

The wiring looked good, but its still doing the same thing. It will accelerate, but then all acceleration is cut off.

The display never shuts off, and if I release the throttle, and hit it again, it will accelerate for a few more seconds.

Not sure whats going on. I guess I will have to wait until I get a freewheel tool to fully inspect the wiring.

amberwolf said:

This is a common problem, and the solution is the same each time, usually.

If it doesnt' have the resistance when the controller is not plugged into the motor, then the controller is damaged, probably FETs shorted that need to be replaced.

If it does have the resistance when controller is not plugged into the motor, then the motor wires are shorted together in the harness, and you need to re-insulate or replace them.

Click to expand...

Thanks for the simple answer. So it has happened to others, that shorting the wires at their junction with the axle can lead to controller failure, FETs being shorted? What's a typical action in that regards? Replace the Controller and throw the damaged one away? Or can the controller be repaired? Are there people who do that?

cruzin said:

The wiring looked good, but its still doing the same thing. It will accelerate, but then all acceleration is cut off.

Click to expand...

The most likely thing based on the symptoms is either a hall wire is open (torn inside the insulation where you can't see it) or a hall is actually damaged electrically inside the hub, if any of the hall wire insulation did get damaged and the wire contacted any of hte phase wires that had damaged insulation.

If you have a multimeter, there are other threads about damaged axle-wires where people were walked thru testing both of those things with one. Sorry I don't have a link, though.

I agree. Most likely a hall wire problem. Easy to test with a voltmeter. While the motor is connected and everything switched on, stick your probes up the back of the hall connector between the black and each of the blue, yellow and green hall wires. Turn the wheel slowly to see the 5v switching on and off.

I will do that today. Its taken apart, and I was going to try to take the freewheel off. Looks like its going to be a pain.

Ill put it back together and test the hall wires.

I put it back together, hooked up everything and probed the harness as stated above.

Red: 4.27 volts, unchanged when turning wheel slowly
Yellow: 0.03 and 3.84 when wheel turned slowly
Green: 0.03 and 2.50 when wheel is turned slowly
Blue: 4.97 and only goes up to 4.98 when wheel is turned slowly.



Im stumped. I have traced the wiring, and I cant find any bad spots. I guess my next step is to cut off the protective layer and inspect the wiring from the harness to the motor. I dont know how I will protect it afterwards, unless I use a ton of electrical tape.

The connections go into the motor, and since I cant get the other side off due to the freewheel, I am unsure as to what to look at next. Anyone know how to get that freewheel off? its a chinese shimano freewheel. I dont have a tool or a puller.

You will need a puller so you don’t damage anything (to be safe), there cheap to buy on ebay. You can protect the wires by putting them in a clear or black tube different sizes are available and will be easier to deal with if you need to get to the wires.

Ahhhhh... then again my idea might not work. I personally would replace the wires from in side the hub motor or its goanna be messy.

If this is a Direc5t drive motor, you should be able to get to the wires by just removing the cover on the wire side, without removing the freewheel or far side cover.

The results you gave indicate two possible things. First, the blue wire is shorted with the red wire, giving full voltage on that side.
The other possibility is that the blue wire got shorted with one of the phase wires, and burned out into an on condition.
That would be less likely, but could happen. Hall sensors aren't that hard to replace, just a bit time consuming to get out of the old glue.

It is a direct drive motor. I should have added that in, Im sorry.

I now have it apart again. The wires go underneath to the other side, and I can see under there to asses any damage.



I will carefully inspect the wires after I remove the protective coating. Thanks

cruzin said:

Red: 4.27 volts, unchanged when turning wheel slowly
Yellow: 0.03 and 3.84 when wheel turned slowly
Green: 0.03 and 2.50 when wheel is turned slowly
Blue: 4.97 and only goes up to 4.98 when wheel is turned slowly.

Click to expand...

Red is power to the halls, so it shoudlnt' change.

If the blue never goes down to nearly zero volts, then something is damaged there. either the wire is broken between the point you measured at and the hall inside the motor and needs to be repaired, or the hall itself is electrically damaged and must be replaced.

It is unlikelyl that it is shorted to the red wire, both because the voltage is not the same between them, and because the reason hall signals go to a higher voltage than their supply is because that voltage is actually provided inside the controller on each signal wire, and all the halls do is short that voltage out when they "turn on" as magnets pass them.

It *is* possible the blue got shorted to a phase and blew the hall on it, though; it's common enough in axle wire damage from twist or impact.

You can test continuity of the blue wire from the point you measured at to whatever point you have access to inside the motor (or even just at the axle exit, if you use a needle to pierce the insulation and stick into the wire itself, then touch that with your meter probe).


As for disassembling the motor, I'd hold off on that until you're sure there's no external wire breakage inside the insulation of that blue wire via continuity test.

EDIT: since you've already got the motor open again, you can at least measure continuity on the blue wire all the way up to the point it disappears thru the hole to the other side. It is probably not damaged after that point anyway, so if it reads ok there, then it is probable the hall has failed and wouldneed to be replaced.

If it does need a new hall, Honeywell SS41 or SS41a are common replacements for these. Search ES for them and you may find there are still some members taht have some to be mailed out cheap.

I know that I have some but I have no idea where they are right now, so I can't help.


If you have a good local bike shop, you can take your wheel to them and have them remove the freewheel, or if they won't do that, they can sell you the tool to use to remove it. Probably between $10 and $20. But the catch is that many of these tools wont' fit over the thicker motor axles, being made for the smaller bicycle axles. Some of them have to be bored out. Ebikes.ca (Grin Tech) has some already bored out for common Shimano freewheel splines.

After careful inspection, I did not see any problems in the wiring. I uploaded a video to youtube:


[youtube]PXsi8qe3KvM[/youtube]

I dont have any wire, or I would just run all new strands.

Im leaning towards it being on the other side of the motor, which I cannot access. I tried banging that freewhell off with a chisel and hammer, hitting one of the little dimples, but it would not budge.



Edit: just read your post right after I posted this, amberwolf. I will do that now. Thank you.

Note that I just edited my post (before you posted) with additional info, so you may want to re-read it.

I ran a jumper wire from the point to where the wires go under to the other side, all the way to the harness. Still reads 4.97 and doesnt change at all when I spin the wheel.


Im guessing that the hall sensor is bad.

I also assume that it is not safe to ride it like this? If so, then I will have to put my stock wheel on and peddle until I get the parts.

re these the sensors that I need? If so, I will order a few of them.

http://www.mouser.com/Search/ProductDetail.aspx?R=SS411Avirtualkey67810000virtualkey785-SS411A


I will have to see if my local bike shop will mess with it. Last time they told me they wouldnt touch an electric hub, but to remove a freewheel they might budge a little.

did you establish that the halls sensor signal wire were toggling on and off yet? does your voltmeter work properly? can you verify it works? 4.27V is very low for the hall sensor power but they may be shorted so that would pull the voltage down on the red wire too. maybe. but the motor has to be intact for you to spin it to establish that the halls are toggling. you should not open the motor until you are able to confirm they are dead. they usually only fail when the phase wires short to the hall sensor leads. if that is the case and you are not capable then this is a dead motor and cannot be repaired since you don't have the tools or skills and the bike shop will know even less.

the green and yellow are both changing from 0.03 to 2.5-3.5 when I spin the wheel. The blue stays at 4.97

My meter is working correctly. When the bike fell, almost all of the wires were skinned and touching. I would really hate to consider this a bad motor, as I havent had it for very long. I got it in December and paid 300 for the kit. Thats a lot of money to just throw away.

then you have to learn how to work on them then. if you take it to the regular bike mechanic then they will charge you a lotta money to tell you they cannot fix it.

the numbers do not make sense though. something is wrong if the blue wire is higher voltage than the power.

do you still have the motor open? if the blue is stuck at 5V constant then open the power lead to the blue wire hall sensor. it may be open circuit on the output and shorted on the inside.

I got the other side open, and partially pulled off. The freewheel comes off with the plate almost 4 inches.

I was able to visually inspect the sensors. I didnt see any visible damage. All three sensors seemed to be in one piece.

Im getting 4.9v from the blue AND yellow at the little board on the motor.


Now I am suspecting that maybe the controller got messed up when the wires were crossed. I dont know lol.

Im done for the day, the sunlight is fading. Thank you everyone for your help.

This is a good reason to have 2 items. One is a motor tester which is about 25 bucks from Ed Lyen in California. The second is a backup controller. BMSBattery sells them cheap. You could also order 2 when you do, since the prices are very low. This is what I do since I have a number of motors some of which work.
otherDoc

dnmun said:

the numbers do not make sense though. something is wrong if the blue wire is higher voltage than the power.

Click to expand...

It's perfectly normal, cuz that's the pull-up resistor voltage from inside the controller, which for whatever reason seems to always be higher than the hall supply voltage on almost every controller/motor I've ever tested.

See my other post above about that.