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The failed PedalCell CadenceX Bike Generator from the previous mailbag video is tested, torn down, analysed, hilrariously laughed at, and dodgily repaired.
00:00 - Failed Pedalcell generator - getting the pinout
02:00 - The PCB
02:40 - Oscilloscope rotation test
03:45 - Dremel speed Captain!
04:22 - Generator teardown
05:32 - Hmm, what's going on with these stator coils
06:00 - Hall effect sensors
06:58 - A-HA Gotcha. These magnets make no sense at all!
08:47 - Someone skimped at the glue factory
11:27 - It's just a BLDC Brusshless DC motor being used as a generator
12:48 - Nothing that can't be fixed with some epoxy
14:00 - Vrooooom!
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#ElectronicsCreators #FAIL #Pedalcell

Just a quick follow up video to a mailbag item that i got. Which is is a pedal cell uh bicycle. Generator usb uh thing so it's basically a here which goes onto your rim here spins around and puts some charge into some super caps. Which then gives you a dual um five volt usb output.

So you can charge your phone. While you're cycling and stuff like that anyway um. It was supposed to be dead. The person who sent this in actually said that they killed two of these things um and we couldn't see anything in the electronics.

If you want to see it here it is here it was just a potted um. Thing so you know not easy to get in there and sort of like reverse engineer. Everything that's the uh rectification diodes for the input um here which just comes from the generator here. There's uh.

Six wires. There. So i thought i just uh a few people asked if i could actually check the motor actually have a look at the output of the motor and see if anything's failed there so that's what i'm going to do in this video. So i'm just going to get a pin out here.

I've soldered on six wires. So i'm just going to go around and try and find the pin out for this thing. That one up there oh no. 16.

Meg why is this 16 meg there okay anyway it looks like that first pin doesn't connect to anything so. That's a not connected next. We got one um. The second pin.

So the second pin here which i'm just going there doesn't matter which direction. They don't actually have numbers. But this pin here connects to this pin here with eight ohms that sounds like a coil to me okay. So that's what we've got there the three which i couldn't uh well essentially non uh connected and three uh to wind in so it looks like we have our three windings in there.

Which is what you'd expect if you have a closer up look at the board and i'm gonna have to because it's a gloss solar mass you can see that okay we've got our three power lines. There and the other i can only see one trace coming off that center pin. So maybe they've got a sensor in there um. Or something i can't see anything coming off.

These. Other pins. Maybe i can try and measure something uh pierce through if you're trying to probe through a conformal coating you can have really sharp probes to make sure you get through. I'll just uh buzz that out to see if these go anywhere.

But yeah basically we've got our three uh winding wires plus our plus potentially up to three sensors there or at least one well. That's strange. I'm getting bugger all out of any of those windings nothing that's 100 millivolts uh per division. And it's not a uh.

It's not a scale thing. I'm getting nothing nothing so what the heck's going on there i mean. This is you know what you'd expect um to measure for a three phase generator. I don't know about the values um eight ohms.

But uh you know like this is like a three phase generator going into a uh diode rectifier and that gives you the output voltage. That's exactly what you'd expect i mean surely to give me something if i'm spinning this sucker. I mean i'm not going hugely fast. But i'd expect to get something like what the so unless.

There is something in there because there was one trace going off which looked like i don't know it may have been going to a power source or something. But like i can like that's winding resistance that i'm measuring surely um. Like what right let's try and actually rotate it faster and you'll notice look at all the spikes coming up when i turn on the dremel. But let's try and knit that's going pretty fast.

I'm getting bugger all out of that nothing that is definitely eight ohms across there okay and it doesn't matter which winding. I choose um it it's just it's getting nothing wow. What the so i don't know are all the windings like fused together or something. Like that aha.

I found an access uh keyway in here. Which gave me access to the two grub screws. Here and ta da. I'm now able to get this sucker off.

We can potentially open. The motor seems like a decent motor. It uses like sks bearings in it what has got any brand in this well okay so much for that there's zero branding on that but as i said. There is an sks bearing in there i believe they're okay aren't they um.

I don't know i i guess i can unfold it open it up there we go here's the peekaboo inside. There i'd have to desolder. But i'm getting um. The bugger all out of the windings.

Oh. I checked the uh winding resistances again yep. So we've got u y w. There there are three windings we've got vdd ground and then h u.

There which h. I presume would be hall effect. So they've got a hall effect sensor on one only one of the windings. Obviously they thought they might have three.

But they only did one so. I guess um. Even. But the generator was generating nothing so ah looks like i can pop this pcb out tada gotcha.

It's our winding um. It's all a bit rough as guards a bit how you doing. But uh like you know don't see any melted windings or anything. Like that so there's your rotor and there's the magnets and the stators and i like i don't know so i would have expected to get what there we go something out of that there you go.

That's interesting. They do have three hall effects sensors in there. But they're. Only connecting up one of them.

So yeah okay fine whatever um. I don't even know why they need that maybe it like it cuts. It off at like a minimum rpm or something like that would be my guess so what i've done is just measured uh. Some dc resistance around the pins on here and the operational one up here.

Which is actually connected um. It measures they all all three measure identical resistances in various combinations on the pins. So there's nothing obvious in terms of like one of them's you know gone kaput shorted whatever so so there you go we're getting eight and a half ohms on the winding well i've put this back on doesn't spin that good now it gets stuck in the duck put on ac and we get something out of it not much aha. I think what's happened here.

I've removed one of those magnets and uh. I think these were originally attached like this so i think what's happened doesn't make sense to have the magnets in this location. I can start like getting them all out and well there we go hello. They're quite powerful.

So i believe what is supposed to happen is well these are supposed to be attached to the rotor and the magnet is supposed to spin like this so it's not really a squirrel cage motor. But why they've got the laminations in there i don't it's just a rotating magnet um in induction motor with the with the stators that's how it's supposed to work with a rotating magnet in there. The only conclusion. I can come to is that um yeah.

These magnets were supposed to be around this rotor like this and you're supposed to have a rotating magnetic field which then induces a magnetic field in the state of rotating magnetic field in the arts moving magnetic field um in the stator coils uh as it rotates and um bob's your uncle you get the um three phase generation out of your stator coil. So i can only presume that these things were originally like stuck on there and they're just flung themselves apart. And when they do they just obviously um. That they just attract themselves over to uh the stator laminations down in there and they stick to it and boom.

Your motor just flung apart and that's why it doesn't generate anything anymore aha. I got fooled for a second there i thought that this looked like um a squirrel cage type motor. Because you got the laminations in there and i thought these look like like at normal distance visual distance. These actually look like the aluminium bars often they use that copper as well to go through there.

But these aren't these are actually these are actually the glue marks between the magnets that were supposed to hold them on so it yeah. It's completely kamagutsu. There they just haven't used enough glue on these things they've just put a little bead down there and that's it unbelievable. I guess he was pedaling too fast.

And it just spun itself way off. Oh wow. That is that is terrible that is terrible muriel. Unbelievable and especially when you've got like using it on a bike like this where the vibrations are going to be absolutely awful you know like no no no no no no aha.

I got the last of them out here and that one just falls off fine. But i can't separate these two so they're like glued together yep yep. So i think i think that's what happened i mean i like i can't see any like there's no like super glue residue or anything like i can't see anything on there but these two are obviously stuck together all the others were kind of like individual and whoa and then the whole thing is supposed to go together oh like that um have i got one out yeah. But even those last two eventually uh fell apart.

So like there's basically no glue residue left on there and like there's none there seems to be none on like the base the curved base of this thing. Which is making contact there was just an absolute little sliver along the edge there and and that's what you can see in the rotor. Unbelievably crap quality wow. It's oh there's a washer in there as well that's come out.

But i think that sucker has flung itself apart. I think that's just piss poor uh construction of the rotor then once they fling apart. They actually magnetically attach to the stator and then it's then it's completely gone ski. No wonder we'll get anything out of it so this seems to be essentially a brushless dc motor being used as a generator you can see the alternating north south maintenance.

There they've marked it like that. But um yeah. I was a bit a little bit confused by the uh laminations in there we got our steel laminations it almost looked um squirrel cagey. So i guess that's to you know confine the magnetic field better or whatever.

I don't know i don't care enough a part enough motors to uh know this sort of thing and of course. Some yeah you'd find three hall effect sensors on a dc brushless motor um. But normally they're a motor to drive them in this particular case. They're using it as a generator and they're.

Only using one of the um hall effect sensors output as i said maybe to you know detect low rpm or something like that because they don't have to uh drive. The thing or anything like that i don't think they've got any synchronous uh converter in there or anything to um to do that i don't think it's that fancy. So yeah. That's it and it's just spun itself apart.

It's completely kamagatsa. So that's just terrible muriel really i mean no wonder i'm surprised it like lasted as long as it did like i do unbelievable okay so i'm going to actually attempt to glue these magnets back on i'm just going to use some arrow tight. I guess some five minute epoxy um. You know just just hold it on temporarily um to try and get this thing back in if i try and actually just put it in with the just the magnets holding themselves around there and onto there then it doesn't have enough strength it just sort of goes like and just sucks the magnets over onto the uh laminations of these stators there hopefully it doesn't ooze out.

But i'll put some on there and just uh try and stick the magnets on uh. I won't give up my uh day job for a roll on the production floor that's for sure well i'm not going to be riding my bike with this anytime soon. But there you go and it doesn't feel very smooth. But uh.

I think i might have goofed the magnets up in there because i um. The little red permanent marker. They had on there well it wasn't permanent they'd all like rubbed off and um. There was like physically handling them.

And it was a dog trying to get it back on so yeah. But there you go that's one volt per division. So it's now working let's try. The dremel again wow look at that okay.

Let's go to 10 volts per division. Try that again look at that 10 volts per division. There you go winner winner chicken dinner so there you have it this uh cadence x pedal cell bike generator convert your cycling motion into electricity to charge your devices um is a load of crap as i said. The person who sent it in has gone through two of these.

And yeah. That's just it just tore itself apart um. That's just a brushless dc motor. They're pressing into use as a generator on the bike and it didn't have nearly enough glue and then it's kamagatsa and how many out there i don't know have you got one of these are there like you know chats on the forums about everyone's cadendex uh generators.

Failing and stuff like that so yeah. There's nothing wrong with the electronics. Which i thought was um looks you know quite decent actually um. And i'm sure if i actually hooked that back up to here it'd you know it'd work again and it was interesting how it uh flung itself apart in there and the magnets stuck to the status and when i took it apart.

I'm going this is kind of like how does this kind of work um. You know because it it just didn't make sense from like a traditional motor topology uh point of view. But it makes sense when you realize that all the damn magnets have flung off the stupid thing and i hope you enjoyed that video. If you did please give it a big thumbs up and discuss down below um.

What you think about the implementation of this uh brushless uh dc motor um and pressing it into service as a generator because that that that looks like all it is it's not like a purpose design industrial type. You know like commercial grade motor in in my opinion. Anyway my vast opinion in our bicycle. Generators um.

Yeah. Let us know what you think down below. Like is this just like absolute garbage or like were they onto something with um. You know using this with they just you know bought a dodgy brand or maybe.

This is just like had a dodgy batch from the factory or something i don't know. But you know when you mount this on the bike. There's going to be a ton of vibration on here. And that's and that's going to you know transfer down to the shaft.

And that's going to be shaking the buggery out of the magnets and i yeah. It's just completely fallen to bits. And it was just interesting how like it felt smooth as silk. It felt like you know before i took it apart.

It was smooth as and we could measure uh the three stator coils in there and so like it should have worked but no there was no rotating magnet so there's no rotating magnetic field you don't get much out of your stator coils when your magnetic field's not moving anyway catch you next time you.


25 thoughts on “Eevblog 1485 – pedalcell cadencex bike generator lol fail!”
  1. Avataaar/Circle Created with python_avatars Robert Backhaus says:

    At least now anyone who has this problem will know how to fix it. It would be good for the first person to do so to document the procedure on iFixit (or elsewhere). The exact procedure to gain access to the spinner grub screws is something this video isn't clear on.

  2. Avataaar/Circle Created with python_avatars IanScottJohnston says:

    What is it with glue!!…..wasnt there an old story of a loudspeaker manufacturer who went bust because they forgot to price in the small amount of glue required to hold the cone to the coil in a large run. Sheesh!

  3. Avataaar/Circle Created with python_avatars kokodin says:

    to fix it you probably should do it in 2 steps
    1 epoxy the core and slip on the magnets but separate them with teflon/polyetylene spacers and wait for glue to set
    2 remove spacers and fill the gaps with more epoxy glue

    it could be better than factory with cheap metal to metal epoxy 😛

  4. Avataaar/Circle Created with python_avatars david haillant says:

    Maybe that's why they recommend, in their "do's and don'ts", to not go over 40mph? (centrifugal force stuff…)

  5. Avataaar/Circle Created with python_avatars Jarno Honkanen says:

    This was interesting, not because faulty product but it relates to topic of my masters of theses "Bicycle dynamo powered charger for electronic devices" (paper is in finish) where I studied HUB generator powered USB charger, done some measurements about HUB generator, and done some simulations.

    3-phase generator is definitely better choice than 1-phase generator what usually is seen HUB generators. More steady output voltage after rectification.

    Quality of construction of generator really matters, it's harsh environment. All that vibrations and etc.. but here rotor construction had extremely bad quality 🤦

  6. Avataaar/Circle Created with python_avatars NICK says:

    A thin aluminum band around the magnets would secure them quite well

  7. Avataaar/Circle Created with python_avatars corey Babcock says:

    When you said completely I said comagaterd before you did lol

  8. Avataaar/Circle Created with python_avatars frollard says:

    It's an interesting segue to how the new Tesla S plaid needs carbon fiber overwrap on the motor rotor…no gear changes means it needs torque from 0-200+km/h. I forget something like 9:1 means the rotor something absurd 30cm(guess from memory) diameter has to spin at absurdium rpms…Rotor needs the carbon wrap just to prevent a nearly solid piece of metal from becoming shrapnel.

  9. Avataaar/Circle Created with python_avatars Steven Bliss says:

    They probably thought they were getting a bargain buying up a bunch of cheap 3p motors at surplus, but they got screwed by the supplier! …WOW!

  10. Avataaar/Circle Created with python_avatars popraw a says:

    This was overrevved or overheated until it failed

  11. Avataaar/Circle Created with python_avatars stelmo502 says:

    Funny– Chinese manufacturing is of high quality and is made to last!!!! I am surprised. NOT

  12. Avataaar/Circle Created with python_avatars dim zen says:

    Seems like glue is heated, melted, and magnets gets free

  13. Avataaar/Circle Created with python_avatars Incendium87 says:

    SKF bearings are good. From what I can tell it looks like SKS is an offbrand trying to look like SKF.

  14. Avataaar/Circle Created with python_avatars SysGhost says:

    Interesting. A friend of mine had this bike generator that failed only weeks after installation. I start to suspect it failed the very same way.

  15. Avataaar/Circle Created with python_avatars Thomas W says:

    That was a good Video !

  16. Avataaar/Circle Created with python_avatars nikize says:

    One of the diodes on the board seems to have had their magic smoke escape.

  17. Avataaar/Circle Created with python_avatars john wright says:

    Proper industrial servomotors can lose their magnets if they spin fast enough. When the magnets fly off, the coils are destroyed. This is how I destroyed a big and very expensive industrial servomotor. Heat-cured tape is wrapped around to hold the magnet assembly together, but a few seconds at speed was enough to break them off.

  18. Avataaar/Circle Created with python_avatars pocoapoco2 says:

    In days past, those magnets would have been glued to the spindle, then screwed to the spindle straight through the back of the magnets and thread into a tapped hole into the spindle. Finally those screw heads would have been chisel/punch-set say they couldn't back out.

  19. Avataaar/Circle Created with python_avatars AffordBindEquipment says:

    Just sent the company the link to this vid. Wonder what kind of reply I'll get…

  20. Avataaar/Circle Created with python_avatars Control Man says:

    Its Broken! What do I win ?

  21. Avataaar/Circle Created with python_avatars leslie meehan says:

    $400 AU way too much

  22. Avataaar/Circle Created with python_avatars James West says:

    I restored an e-bike motor with this issue. I glued the magnets back in place with loctite 638 and replaced the brushes.

  23. Avataaar/Circle Created with python_avatars Bob Cat says:

    A few inches of Scotch tape wrapped around the magnets would be the simplest cheapest fix.
    Hey PedalCell, you can send me one of these to thank me.

  24. Avataaar/Circle Created with python_avatars Scott H says:

    Odd gadget, probably cheaper to get one of those small solar panels with a USB output. Simpler and nothing mechanical to fail.

  25. Avataaar/Circle Created with python_avatars Vishaal Mali says:

    Huge fan of your channel! How I learned all of my EE fundamentals. I’m actually the engineer that designed the electronics. Would love to chat more

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