Troubleshoot 2010 e-bikekit

steelframe

100 µW
Joined
Mar 29, 2017
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8
I have a 36V LiFePO4 front hub drive setup bought from E-BikeKit in 2010 that I am having a hard time troubleshooting. Battery is fully charged (reads 41V on digital meter!) and the handlebar controller turns on when power button is pressed and indicators light up normally, but wheel motor does nothing at all when thumb throttle is actuated. Hand brake lever switches seem good, they are 3-wire hall effect type. I pulled the motor coil 3-wire connector off (Anderson type) and put a voltmeter across all 3 combinations from the controller and I get nothing (with throttle actuated). The controller has an 8" multi-conductor pigtail ending in a circular 8-pin connector that connects with the handlebar computer (model 709 -maybe made by JueShuai), throttle, and brake switches (outer cable has a molded split to these 4 items). Also a 6 pin (5 wire) Scooter type connector for the motor hall effect sensors.
I've looked all over for obvious wire breaks or bad connectors and found nothing. I don't want to start scrapping off insulations from wires to test more voltages before I get a better handle on how the circuit is supposed to work. The company, E-BikeKit says it is too old and they have no schematics or useful help on the phone. Again, the motor cannot be made to turn or even make a noise. Any help would be appreciated!
PS: The controller also has 2 small single connector wires and a 3-wire connector coming out of it that are un-hooked - look like they are extra.
 
Was the problem sudden, happening just when turning on the bike the most recent time?

Or were there *any* symptoms or problems of *any kind* before this?

If the ebrakes are activated (or connection problem exists making the controller think they are activated) then the motor wouldnt' do anything. Often, disconnecting the ebrakes will allow the kit to work if this is the case.

If the throttle is not outputtting a voltage or if the controller is not receiving it due to a connection problem, th motor wouldnt' do anything. You should get just under 1v on the throttle signal wire with no throttle applied, and around 4v with it at it's maximum. Check at the back of the connector on the controller side.
 
Thanks for your help. One of the brake levers has what looks like a good functioning switch. In the process of trying to get the motor working I have cut the wire to the other brake switch, leaving the 3 wires open circuit (the bike needs only one as it has a coaster brake). No difference. I am assuming that the switch releasing (brake lever pulled) closes the switch and inhibits the drive, so this should be fine. Also, the brake switch cables, along with the display and throttle cables, all hard wire together into a common cable that terminates in a circular 8 pin connector in which there is no way to get to the individual pins or wires without opening up and destroying the cable.
That said, it does seem like the drive is being inhibited doesn't it?
Maybe I can open up the throttle mechanism and get voltage reading that way - I will try.
 
I am by NO means an expert, but sounded similar to an issue I was having.

Check my thread, it ended up being the throttle: https://endless-sphere.com/forums/viewtopic.php?f=2&t=86810
 
Its probably the brake cut off. With the three wire Hall sensor type if they are left disconnected the controller thinks the brake is on. Its such a needless over complication of what should be a simple switch. I went thru that with diagnosing a guys Izip where both sensors are integrated into a wiring harness that runs the display too requiring total replacement of the harness. :cry:
 
Thanks for inputs. I still don't have this e-bike motor turning.
Regarding the throttle - I took off the cover (see photo) of the Wuxing and it looks like a solidstate 3-wire sensor with a magnetic strip on the adjacent moving throttle arc. I put a voltmeter on it and measured 4.26V across Blk-Red and 3.4V to .7V across Red-White. So I am guessing that it is working correctly.

Regarding the cut wire to the 2nd brake lever sensor (the 1st lever still has its sensor screwed into it and mechanically works as expected) - I stripped back the 3 wires and measured 4.3V between Red and Yellow and 4.3V between Red and Green. If its true that an open brake circuit signals that a brake is applied and thus inhibits the motor drive, can I short two of these wires out to simulate a closed switch?
 

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I decided to re-solder the cutoff bake switch back onto the wires. The switch itself appears functional mechanically (there is a spring, then a small magnet, then a plastic plunger that moves the magnet into the switch body when the brake lever is released). I am guessing that the when the lever releases, it pushes the magnet toward the Hall effect sensor causing it to conduct. If so, that would be the reason that cutting the wires would inhibit the controller -as that would be like the brake lever being pulled, thus allowing the magnet to move away from the sensor.
The bike motor still did nothing when the throttle was actuated. I then checked voltages on the 3 wires to the sensor and got the exact same readings that I got from the bare wire coming from the 790 controller that I had before I re-soldered the switch back on (see my last post). Regardless of actuating the switch plunger.
So come to think of it - I should only be seeing voltage between one of the pairs of wires (power supply to the senor). There should only be voltage showing up on the third wire when the sensor is actuated (the brake lever is released).
So now I am thinking that something is wrong in the 790 control unit - or a short between the sensor signal wire and power supply wire.
Unless the Hall effect sensor is a sinking type (if there is such a thing) whereby the sensor grounds out the signal wire when actuated. But if that were the case, then everything should be working after re-soldering the switch back on.
 
Sounds like the throttle is working ok.


Most of the switching hall sensors I've seen used in motors and brake levers are sinking-current-types, so the signal wire reads near or even above the supply voltage (because there is usually a pull-up resistor inside the controller, so that without a brake lever attached it would still work normally).

If you read low or no voltage on the signal line at the controller side of things on either brake lever, it may be inhibiting controller operation.


You can test for a short between signal and power by disconnecting the battery, waiting a few minutes for any capacitors inside the controller to discharge, then using an ohmmeter on 20Kohms range between signal and power. It will probably read a few kohms if it's working as it should, and will read less than a few hundred ohms if it is shorted.



Oh, and is it a 709, or a 790? Cuz when I see 790, I think of this:
 
Amberwolf - that is a scary 790! Yes, my handlebar controller is a 790 (I made a typo before). I posted a photo of it a few back.
That's good info that the hall effects might be sinking type. I checked as you described and got over 1K ohms so I think wiring is good.
It doesn't seem that the hall effect switch is working though, since I see voltage on the switch output whether or not I press the switch actuator post.
Before I try jumping the sensor output (to simulate working the switch) I need to better understand the wire/color logic. I don't want to short out the supply. I am measuring +4.3V between read and green and between red and yellow with my meter's red probe on the red wire. Is this indicating that the system is positive common (opposite most of what I am used to in vehicles and industrial equipment)? Or it could be that the green is the common (negative) and the red is sensor power (positive) and the yellow is sensor output that has a pull down resistor in the circuit. If that is the case, that would mean that the hall effect is sourcing type, correct?
 
To find ground, disconnect the battery, and measure from the controller's battery negative wire to the other wires, with the meter on continuity or ohms. Nearly zero ohms means you've found hte ground wires.


If none of the wires on the brake switch changes output level (relative to any of the others) regardless of lever position, with the wires connected normally to the controller and the controller powered on, then the switches are not working.

If the wires do change level but the controller doesn't respond, then the switches are working but the controller isn't working.
 
Very helpful amberwolf. I found ground (or common) for the brake switch is yellow, +4.2V power is red and signal is green. I disconnected (un-soldered) the green and was then, with power on and voltmeter between green and red, was able to verify that the hall effect brake switch is; a) indeed sinking, b) is working (green from switch sinks to ground when the button is released (lever operated).
Non-the-less, the bike motor will not move with the switch in either position or with the switch disconnected - indicating that the controller or the wire harness is sinking the green to ground. I put a continuity meter between yellow (ground) and green and measured 0 continuity with the handlebar controller turned off but continuity with it turned on.
I then dared to short the green to red (apply 4.2V to green) and low and behold the bike motor worked! I just did this for a few seconds - after I detected a smell from the drive controller.
I then tried resistors between the red and green. The motor worked with a 10 ohm resistor but not with a 39 ohm (or higher).

So I think that there is damage (touching circuit) in the drive controller? The control looks a lot like others I have seen pictured of (extruded aluminum body) but has this cable with round connector that goes to the handlebar controller, throttle and brakes which I have not seen anywhere else. Also, there are devices (tri-acs?) in there that are screwed to the case - so it is almost impossible to take apart to get at the circuit board.

Do you think if I permanently install the 10ohm resistor to bring up the signal wire I can the bike that way - or is there another suggestion to fixing this?
thanks.
 
That low a resistance means a high current is being drawn from the 5v regulator in teh controller, and even if it can handle it, it will make more waste heat and use more power than ti was meant to.

Normally pullup resistors are in the thousands of ohms, so I think you'd be better off to find the short in the wiring or controller , if you can.

Regarding disassembling the controller, you can look around at the various "controller repair" or "mod" / "modification" / hacking threads to see how yours might be fitted together (there are a few ways they are designed, so don't know how yours in particular comes apart--some do not have to have the FETs unscrewed from the case, some do, some have removable lids, some don't).
 
Well I'm back to working on this troubleshooting job - a friend who is a electrical tech is going to put an eye on it.
He is asking for a schematic and I have already asked E-bikekit for one but they claim it is too old and don't have any info anymore. I bought the kit in 2010.

So I am looking for a schematic for a 2010 E-bikekit with 36V 350W geared front hub and throttle control. I have attached 2 photos showing the controller and wiring. A similar schematic (that uses a hall effect throttle and hall brake lever sensors with a handlebar control unit like shown would be helpful). The issue seems to be in the brake switch inhibitor circuit.

Any help would be much appreciated.
 

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Those 4 into one harnesses sometimes get internal shorts in the top bit where they split one into 4.

Your system is very simple, but that harness makes it difficult to test. You need to figure out which wire is connected to which pin in the connector at the controller end, then you can make your own harness if it turns out to be faulty.

In the main trunk is:
36v from battery
36v switched by the display to power the controller.
ground
5v for the throttle
throttle signal
PAS signal from the display to the controller
Brake signal wire, which floats at 5v, but can't provide any power
Sometimes there's a wire for the lights
some harnesses are dual purpose. they have two wires for data from the LCD. If you have the 790 panel, only one of those wires is used.

All grounds in the harness are spliced together where it splits
All 5vs are too

You have:
throttle - 5v, ground, signal
790 - 36v, 36v return, ground, PAS signal
Brake x 2 - ground and brake signal


Any short on the 5v would prevent your throttle from working
Any short on the 36v would stop the 5v, so you'd get nothing on the throttle
The throttle would work independently from the PAS signal

That only leaves the brakes. I'd be surprised if there's a short there. You should test the motor with both brake switches disconnected.

All things considered, I think you're looking on the wrong side of the controller. I would think that the problem is somewhere between the controller and motor. Normally, you'd need an e-bike tester ($10) to check them, but if you have the 9-pin motor connector, they can't be tested without making adaptor leads. Show us a photo of the wires from the controller.
 
Re the controller case, those are the mosfets screwed to the case as a heat sink. Sometimes, but not always, what looks like a solid case actually has a lid that separates... Usually you have to completely take off the non wire end, then undo the top​ screws of the other end, and the lid slides off. Again, not every controller does that... And on some it's not slotted on to where it has to slide off, but just lifts off.
 
I don't recall EBK ever selling that particular display, but the do often try shit out, and then will sell it at some point. So that's why they don't have any parts.

In any case, you got a good motor still. I'd scrap the whole thing except for motor, and slap an affordable controller ( with self learn) and new throttle on it, without display.

Strip it down to simple, and get er back running for about fifty bucks. That display is shit, so dump it.

Re troubleshooting, if the controller powers up, first thing is unplug the brakes completely, then with the wheel off the ground, short the throttle wires, and see if it jumps to life. (not really possible with your harness though, easy if the throttle has a three pin plug)

90% of the time, the problem is just in the wires, often a closed circuit on the brakes, or a broken connection on the throttle. Sounds like your problem is not that simple. VERY simple to slap another aftermarket controller on it. If nothing else, it will eliminate all the old wiring.
 
I found this tracing of a Julet harness I did about a year ago if it helps anyone. zoom in to see the colour of the wires in the small circles:

 
Or

http://www.ebay.com/itm/Electric-Bike-Brushless-Motor-Controller-36-48V-350W-For-Electric-Scooters-New-/142185783657?hash=item211aeee169:g:mbcAAOSwHMJYMm32

14 bucks.


http://www.ebay.com/itm/48V-1000W-Electric-Bicycle-E-bike-Scooter-Brushless-DC-Motor-Speed-Controller-/302033172698?hash=item46529478da:g:xogAAOSwqfNXpEdo

35 bucks.
 
Just to wrap up this post in case someone is searching who has a similar problem:
Turned out the solder connection between the Hall effect brake switch and the green (output) wire was broken and the green wire was intermittently touching the yellow (ground) soldered connection, thus inhibiting the drive. A new switch with pigtail was soldered in and everything works!
 
Thanks Steelframe for posting the problem AND the solution.
So often on forums, we see a similar problem to that which we have but it ends when the OP either loses interest or fixes it but doesn't bother to say how.

Cheers Mate!
 
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