Powabyke Ebike Fuse Keeps Blowing

[Wolvyr]

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

 

[Deleted member 4366]

I don't know the wiring, but rather than just randomly join wires togethe, which can do a lot of damage, you should use a meter or trace them to see where they go and come from.

When you get the wiring sorted, the throttle doesn't work until you turn the pedals.

If you have to replace the throttle for any reason, be aware that it works backwards compared with any that you can buy from Ebay, etc.

There are some manuals in this thread:

http://www.pedelecs.co.uk/forum/threads/powabyke-manuals.24105/

 

[Wolvyr]

I don't know the wiring, but rather than just randomly join wires togethe, which can do a lot of damage, you should use a meter or trace them to see where they go and come from.
/

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!

If you have to replace the throttle for any reason, be aware that it works backwards compared with any that you can buy from Ebay, etc.
/

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?

There are some manuals in this thread:

http://www.pedelecs.co.uk/forum/threads/powabyke-manuals.24105/
/

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?

 

[Nev]

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).

Fuses have a fusing factor (number usually greater than 1) for example an old rewireable fuse had a fusing factor of 2. This meant that a 15 amp rewireable fuse would not blow until 30 amps was passing through it. I can't remember the fusing factor for cartridge fuses used in plug tops but I am fairly sure that a 13 amp one would not blow when 13.89 amps is passing through it.

 

[Nev]

In your place I think I would try the following. Make a note of the make and model number of the ignition switch. Search on line for the ignition switch and hopefully get hold of a drawing showing the actual make and break connections of the rotary switch. Armed with that diagram you should then be able to work out what wires you need to connect together. You don't need the wiring diagram of the entire system. You just need to know what connections the switch makes and breaks.

 

[Wolvyr]

I am fairly sure that a 13 amp one would not blow when 13.89 amps is passing through it.

Thank you for this information. I suppose this has debunked my first idea.

Search on line for the ignition switch and hopefully get hold of a drawing showing the actual make and break connections of the rotary switch.

If only life were that simple. Sadly, this is such an old model that has been discontinued for a while. Even in its prime, that documentation seems to have not been in circulation. I've found the code for the ignition switch on the manual (it is PTBATLOKIGN5/21), but searching for this yields no results of worth.


Has anybody had experience with a bike where every time they turn the switch on the fuse blows?
I'm considering looking at getting a new motor controller, though I cannot be certain of the power of the motor so it certainly wont be easy to find a compatible one.

Would it be an awful idea to bypass the fuse on the battery altogether and see if anything happens?

 

[Nev]

Would it be an awful idea to bypass the fuse on the battery altogether and see if anything happens?

Please don't do this, the fuse is the weak link in any circuit. The idea being if there is something wrong (short circuit for example) the fuse will blow before any damage can occur to the circuit (either wiring or components).

 

[Nev]

The part number you posted in the previous post is the number they have for the ignition switch. Is that the number that is actually on the switch and not the number they have used in their wiring diagram. This is just a stab in the dark but I would doubt that they would make the ignition switch. Someone would have made it for them. If you can find out who makes the switch you might be able to get a wiring diagram of the switch from them.

 

[Nev]

As a last resort would it be possible to break open the ignition lock assembly and work out what connections are made or broken when the key is turned. I know you haven't got a key, but by breaking the thing open you might be able to circumvent the need for a key, and hence might be able to work out what is going on inside the switch mechanisem.

 

[Deleted member 4366]

If you fit a normal throttle, it will give high power when at rest, and low power when you twist it open.

IIRC, there are two modes of operation: Something like in one mode, the throttle only works when you pedal, and in the other mode, you turn the pedals to enact it, but it works independently after that. Unless there's a separate mode switch, those two wires are probably something to do with that.

 

[Danidl]

Please don't do this, the fuse is the weak link in any circuit. The idea being if there is something wrong (short circuit for example) the fuse will blow before any damage can occur to the circuit (either wiring or components).

A fuse is actually just a a piece of low melting point wire. If it were rated at 13 amps and 14 amps were flowing through it it will blow given time. Probably on a warmer day. There are different rating on fuses determining how long it will allow an overload current before blowing. ..

 

[Nev]

A fuse is actually just a a piece of low melting point wire. If it were rated at 13 amps and 14 amps were flowing through it it will blow given time. Probably on a warmer day. There are different rating on fuses determining how long it will allow an overload current before blowing. ..

The OP said each time he replaced the 13 A fuse it blew straight away. That would not happen with just 14 amps flowing through the fuse. There must have been a lot more than that amount of current flowing to cause the fuse to blow as soon as the switch was closed.

 

[Wolvyr]

If you can find out who makes the switch you might be able to get a wiring diagram of the switch from them.

Sadly, there was no branding or printing on the switch other than the words 'IGNITION' and 'OFF'. Finding the diagram seems to be futile at this point.

As a last resort would it be possible to break open the ignition lock assembly and work out what connections are made or broken when the key is turned.

This is precisely what I did in the end.
Here's what I found out:
The red and brown wires had been wired so that in every position of the switch, they're always closed circuit. I believe this was done by the previous owner, as they had lost their original key.
The yellow and blue wires were only connected in one orientation of the switch, and based on the pattern of wear on the contacts, i'd assume that most of the time they were not connected together. From this, plus some information on the internet, I've concluded that red and brown definitely are power and should be closed circuit, while blue and yellow are used to determine the mode of the bike - whether its twist and go, or pedal assist.

IIRC, there are two modes of operation

I can confirm this, which explains the blue and yellow wires.


I've been doing more work on the bike, so here are my updates:

The glass tube fuses I've been using are blowing one after another, and I'm running out. I have a lot of blade fuses, so I decided to wire in a blade fuse holder for easy and fast replacement of fuses as a temporary measure until I can pinpoint the fault.

I also wired up a 2 position switch between the red and brown wires which were going to the ignition, so I can manually operate it for fault finding.

So now equipped with easy to replace fuses and an ignition switch I began testing to work out under what conditions the fuse would blow.


First, with the ignition switch off, I flicked the battery switch on. No fuse blow - naturally, since there is no current draw anyway.

Next, I flicked on the ignition switch. Strangely, there was no fuse blow - unlike every attempt before. Now twisting the throttle, unfortunately there was no response from the motor. Pedalling the bike half meter, for some reason, resulted in the fuse blowing.

My first guess was perhaps the motor was generating a reversed current that the fuse really did not like, which seemed odd. I have yet to find anything to confirm this, though my hunch is that this isn't the problem.

After replacing the fuse, I tried again. Ignition switch off, battery switch on, then ignition switch on. Now turning the throttle, the bike is stationary, no motor reaction, and the fuse blows! No movement, no current generation! This is part of the reason I don't think the motor generating any current is the issue here, as well as the fact the controller likely has some protection from reversed currents.

It almost seems like the motor controller just loves to draw massive currents at totally random times, which is making the fault finding process incredibly difficult.

Some more information I've gained is that with the battery and ignition switch on, and the throttle twisted, there is no voltage making it to the battery terminals. So I can confirm that the controller is not actually sending anything to the battery.


With barely a thought on what direction to go down next, I've considered a new route, though frankly I'd rather fix the original problem than have to go down this rabbit hole.
So here's my plan:

Since the battery itself is fine, and the motor appears to have no issues either, that leaves the motor controller as the culprit.
Whether its the wiring or the controller board itself that's the problem I do not know, since I cannot find a wiring diagram anywhere, even after contacting the manufacturer. Knowing this, I should try to replace the controller.

Issue 1 is that I'm not certain of whether my motor is brushed or brushless. I understand that brushed motors generally have 2 connections, and brushless 3, but my motor seems to be a strange one. There are 4 wires coming from the controller down to the motor, which go into pairs, that go to 2 terminals (2 wires per terminal). From those terminals, one wire each (so 2 wires total) go to the motor itself. I'd assume this is a brushed motor because it has two terminals, but why would there be four wires coming from the controller?

Issue 2 is that I cannot confirm the power of my motor. The seller listed it as a 500w, I believe it to be a 200w, though its physically larger than a 360w hub motor I already have lying around (broken). I don't want to purchase a 200w motor controller, only to find out I'm massively hindering the motor's output. What methods/strategies can I employ to find out what the power rating of my motor is? (note - there is no printing on the motor itself, and the casing appears to be different to the hub motor in the pictures in the bike's documentation PDF I have)


After I know this information I want to try out using an Arduino to control the motor using a 36V motor driver board. This way I can program in functions that I would like to have on my bike.
Does anyone know if somebody has tried and/or documented this on this forum or elsewhere before? I'm looking around the internet myself but so far haven't found much.

Thanks to anyone who took the time to read this long post. I've spent so many hours on this bike already, here's to hoping I get it working soon!

Edit: I found <this motor driver> which seems to be perfect for this situation.
Also, <this driver> seems to do the job and is significantly cheaper.
Thoughts?

 

[Nev]

.
It almost seems like the motor controller just loves to draw massive currents at totally random times, which is making the fault finding process incredibly difficult.

Is it possibly to disconnect all the wires going to the motor? If so then once you have done that then operate all the switches (ignition, throttle etc.) to see if the fuse blows. If it does then at least you will have eliminated the motor as the probable cause (unless your really unlucky and have more than one fault on your bike).

BTW I admire your tenacity with trying to sort out the problem I suspect most people would have given up long before now. I really hope you get it sorted, and perhaps some of the experienced electric bike people on here might give you more help than I am able to.

 

[Deleted member 4366]

It sounds to me like the mosfets in the controller have blown or you have a short on the motor wires somewhere.

 

[Wolvyr]

Is it possibly to disconnect all the wires going to the motor? If so then once you have done that then operate all the switches (ignition, throttle etc.) to see if the fuse blows. If it does then at least you will have eliminated the motor as the probable cause

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!

BTW I admire your tenacity with trying to sort out the problem I suspect most people would have given up long before now. I really hope you get it sorted,

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!

It sounds to me like the mosfets in the controller have blown or you have a short on the motor wires somewhere.

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?

 

[Deleted member 4366]

The throttle has a hall sensor in it. it uses a 5v supply (normally black and red wires) and a signal wire that gives between 1v and 4v depending on its position. To test it, wire three AA cells in series to power it, then measure between ground and the signal wire to see the output.

 

[Wolvyr]

To test it, wire three AA cells in series to power it, then measure between ground and the signal wire to see the output.

Thanks for the instruction!
I did this and did indeed see a ranging voltage between 1 and 4 volts on the signal connection, with 1v at full throttle and 4 at no throttle.

From what you were saying previously, I gather that all other throttles will give 4v at full throttle and 1v at no throttle?



With the electrics taken apart so I could test the throttle, I decided to closely inspect the controller board for any abnormalities.
Carefully observing each component, all seemed fine except one slightly off-coloured resistor. 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, along with their ratings printed on the silkscreen. Sadly, R22 does not have its rating printed.

I'm still stuck in the dark, but i've gained two useful pieces of information today.

My big question now is, would a resistor that small really cause my battery to arc at the terminals and the 15A fuse to blow?

 

[Deleted member 4366]

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.

Your throttle is working correctly. As I said before, it's backwards compaared with a normal one.

you need to test the mosfets:
https://www.google.co.uk/search?q=how+to+test+a+mosfet&rlz=1C1CHZL_enGB733GB733&oq=how+to+test+a+mosfet&aqs=chrome..69i57j0l5.5455j0j8&sourceid=chrome&ie=UTF-8

 

[flecc]

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.

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.
.