Powabyke Ebike Fuse Keeps Blowing

[Wolvyr]

That resistor will be for a different version. it can't fall out. maybe it's for a different voltage battery or a different input device somewhere.

I considered this, though i'm still undecided on what to do about R22. While it seems reasonable enough that the controller may function fine without it, to me it also looks like the pads had been soldered as you can see some brown/orange discolouration from the flux on the R22 pads. However, there is no spike or obvious break point that you'd expect from a resistor that had snapped off. Even if I wanted to put a resistor in there to see if anything happens, I wouldn't know what value to use. Seems like a dead end.

you need to test the mosfets:
https://www.google.co.uk/search?q=h.....69i57j0l5.5455j0j8&sourceid=chrome&ie=UTF-8

Thanks, i'll try this next. Can MOSFETs be tested in circuit, or do they need to be isolated like resistors?

Current at startup on the 200 watt 36 volt Powabyke brush motor setup is 600 watts, A to B published the graph some while ago.

If i'm understanding this correctly, I should expect there to be a instance of 16.7A (600w/36v) being drawn from the battery as soon as i flick the ignition switch on? Even so, from what the other posters here are saying, this still shouldn't fry a 15A fuse, right?
Would it e an awful idea to try out a 20A fuse and see if anything different happens, or is that asking for my MOSFETs to blow?

 

[Danidl]

Following your suggestion, I tried this. With the motor diconnected, the same issue persisted. While I may be no closer to the problem, I at least can rule out the motor (to some extent). Thanks for the advice!


Thank you very much I'm an electrical and electronics engineering student - if I gave up, I wouldn't be able to look my lecturers in the eye aha!



If it were the MOSFETS, do you know of any methods to confirm this?
Wires shorting may be a possibility, though from what i've seen, there aren't any places I imagine a short could happen.

The reason I think a short may be possible, is because after following Nev's advice on disconnecting the motor, I found that the fuse was actually breaking under these conditions:

Battery and Ignition OFF
Battery switch ON
Ignition switch ON
- fuse okay
- twist throttle and there is no reaction from the motor
- the LED's from the motor controller also have not turned on, indicating is not actually receiving power / working

rock the battery side to side
-fuse blows

Then inspecting the connection point between the terminals of the battery and the dock connecting it to the motor controller, there are burn marks on the metal terminals, in addition to a rattly/buzzing noise at the same time as the fuse breaking.


Next I'd like to test whether the throttle works, however I don't know what to expect.
Is the throttle just a potentiometer, and the controller uses it alongside an on-board resistor to act as a potential divider and it reads the voltage as the input? Or does the throttle itself have both resistors, and the controller board directly reads the voltage?
Perhaps it depends on the model and build of the throttle. Anyone have some experience?

As an electronics student I would be tempted to ask what year... . .
Now the calculation you are making say that the current will be 14 amps is not necessarily true... A motor not rotating presents as a short circuit, and the current which flows will be limited by whatever other resistance is in the circuit.it is only with rotation that one gets a back emf to limit current.. .
To check whether a mosfet is alive or dead, will require removing the drive to the gate, and then measuring the resistance drain to source, and then apply a voltage of about 6 v , a PP3 9v battery will do between gate and source.. the actual voltage depends on the moset, so you need to pick up a spec. l sheet. The test would best be done with the gate unsoldered and no power supply attached., as the external voltage could.. actually likely to blow the controller driving the gate...
I actually suspect a short circuit to ground, which is very hard to test with a conventional multi meter ,as motor windings resistance is so low..

 

[Nev]

I actually suspect a short circuit to ground, which is very hard to test with a conventional multi meter ,as motor windings resistance is so low..

I don't think he needs to worry about motor resistance and back EMF etc. If I have understood what he has written correctly. The fuse keeps blowing even with ALL the wires to the motor disconnected. Therefore unless proven otherwise (ie. two different faults on his bike) we can at the moment assume that the fault does not originate in the motor, but there is a short circuit somewhere else.

 

[Deleted member 4366]

If i'm understanding this correctly, I should expect there to be a instance of 16.7A (600w/36v) being drawn from the battery as soon as i flick the ignition switch on? Even so, from what the other posters here are saying, this still shouldn't fry a 15A fuse, right?
Would it e an awful idea to try out a 20A fuse and see if anything different happens, or is that asking for my MOSFETs to blow?

15A sounds much too low to me. I would use a 25A one.

No significant current should go through the fuse until you open the throttle or pedal, but if the MOSFETs are blown in a brushless controller, they fail to an open state, so the maximum current that the battery will supply tries to rush into the motor, like instant full throttle, so be careful. Make sure that the wheel is off the ground when you put in a stronger fuse.

 

[Danidl]

I don't think he needs to worry about motor resistance and back EMF etc. If I have understood what he has written correctly. The fuse keeps blowing even with ALL the wires to the motor disconnected. Therefore unless proven otherwise (ie. two different faults on his bike) we can at the moment assume that the fault does not originate in the motor, but there is a short circuit somewhere else.

Ok that makes it easier, again it is probably still a short circuit. .. my next suggestion is an old troubleshooting trick... Replace the fuse with a car headlight bulb. If there is no short in the wiring the bulb will only glow dull red at best. Manipulating all the wiring harness and twisting wires etc might cause the bulb to brighten, then you have found the short... If the light stays bright , then disconnect leads in turn and so isolate the high current node...
Incidentally my reference to back emf etc was to remind him \ her .of the .Physics of motors and that motors can draw a lot more current than the calculation might suggest.

 

[Roger Holmquist]

[QUOTE="Wolvyr, post: 437557, member: 16339"



....
. That is, until I looked adjacent to it - there is a resistor missing!
See below for what I mean:

https://drive.google.com/file/d/1tz781btKckf7zqxYbwBtKFh8n1ScIa8k/view?usp=sharing

The far-right resistor is slightly off colour, and to the left of it is 2 pads with the print R22 between them. I am unaware of whether this resistor came off and is the issue, or whether it was never needed in the first place. Unfortunately, there is no circuit diagram for this board either. However, I did find another use with the same controller board (but a different issue altogether) that happened to upload a video, in which you can see his controller board.

At 0.5x speed at 15 seconds in, here is what you can see on his board:

https://drive.google.com/file/d/1TrMQsNCMd9PQlNAV2ET81Iy_JY6Qqhpv/view?usp=sharing

It's certainly not easy to see, but im sure its there - a resistor at the pads for R22. Sadly, the resolution is so poor you can't make out the colour bands, or any colour at all for that matter. Any ideas on how I can find out what size resistor to put in the place? And just as a note, R22 does not refer to the resistor value, but is the resistor's name, as all other resistors have a name,..
....

I don't believe there is any resistor missing here.
It's very common with unused components in electronic boards, it usually boills down to a modified design.
/Roger


?[/QUOTE]

 

[GettinBetter]

As Roger says above, a missing component is very common on circuit boards, I would lean towards your analysis on post #16 where you mention that rocking the battery blows the fuse, surely this indicates that the problem is inside the battery box or the cable connecting to it, or even the cable itself. My board has a date marking of "Jun 26 2000" on it but it's different to yours.

 

[Ajax]

Don't worry, I did my research. I'm no stranger to a multi meter, and Im comfortable reading circuits. I'm 95% confident that the red and brown definitely are power connectors, and that the blue and yellow are digital signals. The red wire definitely goes directly from one of the battery terminals, while the brown goes to the motor controller. Alternatively, the blue and yellow wires are both a significantly smaller gauge, and both come from the same region (labelled P2) on the motor controller.
I know the dangers of randomly connecting wires first hand!




I'm not sure I follow what you mean here. Are you saying I would need to twist the throttle away from me (anti-clockwise looking at it from the right) to accelerate opposed to the traditional clockwise twist?



Thank you very much for this link! The manuals do not answer my question, but they contain valuable information, nonetheless




On another point, I have some theories as to why I'm having the problems I am, and was hoping to hear some input from somebody far smarter than I.

Theory 1 is that upon startup, the controller draws full current for a brief moment causing the 13A fuse to break. Considering the seller listed the bike as a 500w motor, its theoreticall possible that the motor could draw up to somewhere in the region of 14A (500w/36V = 13.89). Though I very much doubt that this is either a 500w motor, or that it could really draw that kind of current, I still want to consider this as a potential cause. I will picking up a 15A fuse and testing that out to see how it goes. Any thoughts?

Alternatively, theory 2 is that having the power cables that I cut from the ignition permanently closed circuit may be an unfavourable condition for the motor controller. Perhaps the key is to have the battery connected, and then have the power cables make contact via a switch, as they would have originally with the ignition switch. Any ideas on this?

These are the steps I plan to take next. Anything else I should try?

Hello,
I'd like to start by saying its been a while since I last posted, so if I've forgotten any important rules on where/how to post please don't hesitate to remind me.

I've recently picked up a Powabyke electric bicycle - model unknown.#
https://drive.google.com/file/d/11FX3RHnrYbn4WtIkfaOp8y7_aRVBgSAR/view?usp=sharing

I have reason to believe it is a Powabyke Commuter, though I have no way to be certain.
The battery is 36V, and the seller claimed the motor is 500w, though I quickly realised they had no clue what they were talking about and this must surely have a 200w motor in like the other Powabyke Commuters.

The bike came with no charger, so after taking the battery apart, drawing up a wiring diagram and finding out which of the two types of electrical connections was the charger, I left it to charge overnight - no problems here.

The next day I attached the battery to the bicycle and flicked the switch, only to realised that there was a key that the seller had lost which was required for the ignition switch. I decided on cutting out the ignition altogether and have it permanently connected, as the battery itself had its own on/off switch which i thought would be enough for now. I then planned to cut the wires before the ignition switch and have them connect to each other.
See below for the wiring on the rear of the ignition switch:
https://drive.google.com/file/d/1PEten0HdfpkotVQ7mpqoswFfmCeN0fN3/view?usp=sharing

After spending some hours looking for documentation/a wiring diagram for the K3602 motor controller on the bicycle, I failed to find anything remotely helpful. I decided to take it into my own hands and make a few assumptions. I first assumed that the red and brown were obviously the 36v power, and that I should just connect these directly, and secondly that the yellow and blue were just a digital signal to alert the controller that the ignition was in the 'ON' state. Again, I had no wiring diagram, so was only using intuition.

Having no other leads on how to go about this, I went forward on connecting those wires, like so:
https://drive.google.com/file/d/1xGplslkdJo7zIoHGsLolHgfgtCfoSEMv/view?usp=sharing

(Red going straight to brown, and blue going straight to yellow - I know the insulation tape looks awful here but it was only to test whether this would work).

I reassembled the electronics on the frame and attached the battery. Making sure the fuse on the battery was fine, and the battery was still outputting at least 36v, I attached it, flicked the on switch, and hoped for the best.

To my frustration - nothing! Checked the battery output - 0v. Checked the fuse - blown. After replacing the fuse and trying again, history only repeated itself. Fuse after fuse was blowing after connecting it to the controller and flicking the switch. I then tried removing the blue and yellow wires altogether to see if that made a difference, which it did not.

The motor does not make any movement - though I know it is functional as bypassing the motor controller altogether does cause it to spin. I cannot find any documentation on this bicycle or its controller out there, though I have contacted Powabyke via email and am waiting for their response.

Does anybody have any clue why fuse after fuse keeps blowing? Did I make a stupid mistake while reconnecting the wires from the ignition switch? Any suggestions at all?

I am very grateful for any help anybody may be able to offer, so dont be shy!
Thank you for taking the time to read this and have a good day

I would look for a short on the main wires from or near the battery, causing the postive to connect to the negative.

The short which occured when you pedeled for a short while, suggest a lose connection, where the vibration of pedeling made the connection.

Like wise when you jiggled the battery, you made the connection. I would look for a dry solder. I think you are over thinking the problem
when you suggest the motor's draw could be responcible.

As for the key circuit, that should be a simple braker circuit on either the positive, or the negative pole, not both. eg it completes the flow on that pole from the battery. Occasionally you'll have a controller with a special 'key' circuit, acting like a relay circuit, which takes a nominal current to complete a higher current circuit.

Btw where is the fuse in the circuit - is it just after the battery, or integral to the battery? This could provide another clue as to which pole to look for the short.