Help please

[thegavo]

Hi guys, just hoping someone could help me with how to proceed.
My wires have touched whilst out on my 48v, 1500w brushless ebike, it's the green, yellow and blue wires that head to the hub motor from the controller, I had noticed heat where they joined the controller wires, I took it apart, cleaned the loops and bolted them together again, then put more insulating tape on. It's been fine for ages but still got hot, I kept a check on it, but today alas it got hot hot, the insulation failed they touched and first I knew was when I tried to pedal off, there was resistance, it didn't move so I twisted throttle and there was a juddering noise. I immediately shut it off went in battery bag and found the insulation was so hot and the wires were shorted, I separated them and tried the throttle but still it just juddered. Even with battery off, if I try to turn hub wheel with wires connected it has loads of resistance until I disconnect, then the wheel turns, I've just looked in controller, no smells, nothing obvious to see. So how can I know if it's damaged the hub, or if it is indeed the controller, any help would be much appreciated. Thanks Gavin

 

[Benjahmin]

As an electrician, heat like that says to me that you've got a bad connection. I think that the three wires you mention are the phase wires to the motor. The juddering you mention sounds like one phase is burnt out or not connected.
No doubt one of the pedelecs wizards will be along shortly to help you.
In the meantime disconnect the battery - just in case.

 

[thegavo]

Thanks, just hope someone sheds some light, I'm scared to replace controller if it's not the problem. If it's in the hub it might knack the new controller ?

 

[Danidl]

Thanks, just hope someone sheds some light, I'm scared to replace controller if it's not the problem. If it's in the hub it might knack the new controller ?

If the hub were knackered and had short circuit s it would destroy a new controller.

If the wires coming from the controller shorted together such that large currents came from controller,and melted insulation. I would suspect that one of the three sets of transistors in the controller is burnt out. You have said that it is a 1500w motor so it is drawing about 15 amps per phase that is a lot of current.. if that current can melt insulation on a long stretch of cable, how much more temperature will be produced in the confines of a small box.
Thinking logically, if two wires external to the hub motor shorted, the current will flow through them bypassing the motor in the hub, so there would be no reason for it to have been damaged. If you have access to a multimeter with a low resistance range, and disconnect the three wires going to the hub measure the resistances between each of the three wires and also between the wires and the metallic casing of the hub motor. These wires go to coils of wire inside the hub called windings. The resistance between each winding will be low in the order of a few ohms, but should be about the same between each winding . The resistance between any wire and the hub should be very high 100k ohms or higher.
If you get readings like that you could reasonably infer that the hub is undamaged.

 

[thegavo]

Thanks for this, I shall buy the replacement controller.
what would be the best method to connect these wires into the new controller when it arrives, I had bolts thru the round hoops they were supplied with, to link them, I thought that would have been a good connection, but the heat says otherwise, thanks again

 

[Deleted member 4366]

It's easy to sort out the cause:

1. Disconnect the motor cables. Make sure that they can't touch each other. Turn the wheel. If there's resistance, there's a problem in your motor or cable. If there's no resistance, the motor is probably OK.

2. Reconnect to the controller. If there was no resistance disconnected, but resistance when connected, you've probably blown a mosfet or two in the controller or the motor wires are shorted inside the controller case.

3. Remove all the screws from both ends and the side of the controller. Slide the insides out. Check the three motor wires first to see if they're touching. Look at the row of black mosfets that were screwed to the side. Are any blown or do they stink of burning?

4. With nothing connected to the controller, measure the resistance between each motor wire (on the controller) and the battery positive. They should all be the same (range 10k to 14K). Do the same for the battery negative. they should be the same as each other, but not necessarily the same as the first three, still in the range 10k to 14k. Any anomalous readings means that a mosfet is blown, in which case you need a new controller.

Whatever is wrong, the cause is that you went too slow for too long with high power.

It's normally the crappy PVC coated wires on the controller that melt before the ones on the motor cable. If that's the case, unsolder them from the PCB and solder the motor cable directly to the PCB.

 

[thegavo]

I slid controller out earlier, there were no visual clues and the smell inside was lovely, like new even, but the hell I had putting it back together... individual metal plates to hold the side bolts, what a pig.
With regards to how it happened, I did a lap round our field (2 miles) ish, absolutely flat out with my dog running with me, when I stopped then tried to go again, nothing ..

 

[Danidl]

Thanks for this, I shall buy the replacement controller.
what would be the best method to connect these wires into the new controller when it arrives, I had bolts thru the round hoops they were supplied with, to link them, I thought that would have been a good connection, but the heat says otherwise, thanks again

The description of the connectors you give would fit crimped eyelet type and these would be the suitable replacements. You can purchase these in any maplins, bring an old one with you to ensure the proper diameter. These are single use components . Bare a length of the wire insert it through the open cylinder end and then squeeze clamp the cylinder until it collapses. Ideally it will form a cold weld with the wire metal and be clamped in place also.the aperture in the cylinder must match the wire diameter and these cylinders are colour coded. There are specific tools designed for this clamping , but an ordinary vise grips or good electricians pliers can be used. I have used the cable cutting edge in the electrician s pliers to get enough pressure, and tried to ensure it did not shear through

Maplins will also be able to supply suitable gauged cables. Try and ensure that the replacement connections are the same order as the original.

I would agree with d8veh, that you open the controller, it's probably failed , but nothing ventured nothing gained. It might be ok and simple cable replacement might get you back on track....

Update having read your post... If it smells ok then it is likely to be still ok . You might be lucky.

 

[Deleted member 4366]

I slid controller out earlier, there were no visual clues and the smell inside was lovely, like new even, but the hell I had putting it back together... individual metal plates to hold the side bolts, what a pig.
With regards to how it happened, I did a lap round our field (2 miles) ish, absolutely flat out with my dog running with me, when I stopped then tried to go again, nothing ..

If you want the answer, do the tests in sequence instead of trying to guess.

 

[Danidl]

If you want the answer, do the tests in sequence instead of trying to guess.

Agreed

 

[thegavo]

Hi, if it wasn't clear in my post the bike is not working.
I genuinely don't think I have the skills needed to try and reassemble the controller a 2nd time, in fact, it was just pure luck that I got the metal tabs to line up for the bolts in the side of it.
The kit was from leaf bike.com and he lists replacement controllers but they are £135 delivered, seems a lot when you look at eBay, you can get a 1500w 48v controller for less than £40, I have no idea if it would be compatible tho

 

[Deleted member 4366]

You don't need to dismantle the controller to turn the wheel!

 

[Danidl]

Hi, if it wasn't clear in my post the bike is not working.
I genuinely don't think I have the skills needed to try and reassemble the controller a 2nd time, in fact, it was just pure luck that I got the metal tabs to line up for the bolts in the side of it.
The kit was from leaf bike.com and he lists replacement controllers but they are £135 delivered, seems a lot when you look at eBay, you can get a 1500w 48v controller for less than £40, I have no idea if it would be compatible tho

..
Let's back. Up a few stages. ..
Your bike at present is junk. It does not work. There are any of a number of things which could be wrong with it and only one way that it will work ... When all of the faults are rectified. It is possible that your bike has multiple faults not just one because sometimes a single fault can create a cascade of other faults. A short circuit in a circuit can create excess current which blows fuses and electronic circuitry. Hopefully you have just a single fault.
The likely faults are
1 defective cable to the hub motor either shorted between two phases or an open circuit. This can be repaired by anyone with at least one hand and a head
2 a defective motor where one of the windings has burnt out making a short circuit accross it's windings or to the metal housing. This is not user repairable
3 a fault in the controller. User repairable by experienced technician,. But not you.
Using a number of simple measurements you should be either able to isolate the defective regions or maybe even effect a repair. We have suggested what these measurements should be.
If you have access to a multimeter, simple measurements help pinpoint the problem areas quicker.
From his vast experience d8veh has suggested that a juddering vibration instead of smooth rotation is indicative of current not flowing in one of the three windings of the motor. And he has given you a process by which you can test mechanical damage to the hub. The rotation test
I have given you numbers that you might expect when measuring electric resistance in the motor. Hopefully the motor is still operational. D8VEH is of the opinion that they are very robust.
Even if the controller is still ok, you will need to replace the defective wires. I have described a process for doing so.using crimp connectors. Hopefully the only problem is a defective lead and replacing that requires only common sense and using crimp connectors.


If when you replace the wires, it does not work then your problem is likely the controller, and based on what you have said to date, you would be better advised to get it from the original supplier. .. some eBay vendors ,may look low cost at first sight because they omit transport and delivery,
And returning it from junk status to valuable product.
These are the processes by which a shop would go about repairing the bike.
So best of luck.

 

[thegavo]

Yes all fully understood, very informative, very helpful and massively appreciated, it really is , Will update as I progress

 

[Ultrafunkula]

Hi, if it wasn't clear in my post the bike is not working.
I genuinely don't think I have the skills needed to try and reassemble the controller a 2nd time, in fact, it was just pure luck that I got the metal tabs to line up for the bolts in the side of it.
The kit was from leaf bike.com and he lists replacement controllers but they are £135 delivered, seems a lot when you look at eBay, you can get a 1500w 48v controller for less than £40, I have no idea if it would be compatible tho

If u need controller or a motor that'll replace with top quality try these guys at grin

http://www.ebikes.ca/shop/electric-bicycle-parts/controllers.html

 

[thegavo]

Replacement controller ordered on Monday, just a waiting game now for a while

 

[thegavo]

Update .. new controller arrived, fitted and bikes working again, thanks for all the help

 

[Danidl]

Replacement controller ordered on Monday, just a waiting game now for a while

Well done