Motor perhaps overextended?

E-driver_

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I have a bike with a 250 watt motor.

I have overvolted this bike quite a lot. So I have a controller with max current of 25. And a 48volt battery 17AH.

When going up a slope earlier today. The motor then started making all kinds of strange noises. At least I am 80% sure this sound comes from the motor.

The battery connections still shows me 48 volts so I don't think the battery or controller have taken any damage. But the motor gave me a lot of strange sounds. It still runs but with a strange sound. Any idea what this is or how I can fix it?
 
harrisonpatm said:
But it should be close, and chances are if you rewind a motor by hand, it's not going to have the exact same specs as it did before, due to human hands being less precise than machines.
The only *possibly* machine-wound ebike/scooter/MC motor I've seen are the Ultramotor/TDCM brand. Everything else Iv'e seen has been almost certainly hand-wound (often badly, some quite well, but still not machine wound).

If you know of specific machine-wound motors, I'd be interested in seeing them to compare. :)

Example of an Ultramotor that *might* be machine wound:
file.php



Examples of some almost-certainly hand-wound motors (there would be more but most of the pics from that far back seem to be gone):
Fusin
file.php

9C (nine continents)
file.php

file.php

Crystalyte HSR3548
file.php

file.php
 
Fair enough. I don't work with ebike motors very much, mostly with a variety of lots of other kinds of motors. Not usually BLDCs, and what I've scrapped and disassembled is almost always machine wound. You know more about ebike motors than me. But I think my point still stands, so I'll rephrase: if he's planning on rewinding his motor, for whatever reason, his relatively inexperienced hands are not going to be able to perfectly match specs to what it was before anyway, however it was wound, so that should be taken into consideration.

I still say go for it. It's sort of mind-numbingly meditative.

What's also meditative, is watching the machines do it. I love those videos.

https://www.youtube.com/watch?v=C6qhP6mO2EM
https://www.youtube.com/watch?v=6a2kpaUzAWA&t=318s
Edit: this second link does indeed feature machine windings of what looks like BLDC stators. What kind of motors? Don't know, but it is fun to watch. Starting at 4:30
 
harrisonpatm said:
I still say go for it. It's sort of mind-numbingly meditative.
That's true....the only one I ever rewound myself (more than a decade ago) was brushed, but I knew little about power demands of systems and interactions of various things, so it turned out to be pointless (even though I rewound it the same as it had been, and it worked fine, it just wasn't enough of a motor for the job).

FWIW, most of the motors I have or have worked with are pretty old, so these days they could be more machine wound...others could probably say better than me.


What's also meditative, is watching the machines do it. I love those videos.
https://www.youtube.com/watch?v=C6qhP6mO2EM
Hmmm...I can imagine a piece of music for this... This one doens't sync up right but could probably be edited to do so (I know I have a better fitting one somewhere but I don't think I have it uploaded):
https://amberwolf.bandcamp.com/track/under-the-frozen-sky

FWIW, the brushed motors shown first in that vid look a lot like the one in my big Ryobi string trimmer (AC powered), Later on there's some that look like the little "Unite" motor I rewound. Some of them (like the ones with the coils left hanging off (for what later process?)) I don't recognize from anything I've had apart. Toward the end they show some cieling fan motors...which I did start the process of trying to reuse one of as a BLDC motor:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=19516
but was never able to finish it (I probably have the skills and tools now, but I'm not sure if I will ever get back to it :( ).



https://www.youtube.com/watch?v=6a2kpaUzAWA&t=318s
Edit: this second link does indeed feature machine windings of what looks like BLDC stators. What kind of motors? Don't know, but it is fun to watch. Starting at 4:30

Certainly seems to be some type of 3-phase motor, skipping two teeth for each winding. The one after that looks like an induction motor (pretty similar to the one in my biggest box fan).

For most people it would probably be relaxing to watch...but my mind becomes active watching the process, to see each step and movement to learn from it and figure things out.... I can't turn that off, and sometimes it's annoying. :(
 
My apologies for this side track, but anyone that appreciates hand wound motors MUST see mountain girl Lin Guoer and her YouTube channel. Amazing…

https://youtu.be/mKWJnC9Ype8
 
The bike that originally had this rear wheel motor is now almost rehabilitated. It has a very strong rear-only motor now.

I dismissed my first idea of making it a two wheel drive, since the rear wheel with the copper wire is of course busted. So I put an extra strong rear motor wheel on it instead.

But perhaps the other busted wheel can come in handy in the future when I get time to do a two wheel bike again and if I manage to fix the copper wire.

Since this thread is about this bike I thought I could post my new problem here instad of making it a new thread.

The thing is that the bike is now working very smoothly. Only thing is that this new motor wheel also cuts out sometimes. Now, I have read several threads about this. And I suspect that this might be the BMS of the battery that kicks in when the new controller pulls too much current ?

The battery that I planned to use for this bike is a 48volt 17AH battery and looks like the pictures below. But I am thinking perhaps it is not strong enough or has a bms that cannot handle the current.

Do you think this cutoff is occurring because the battery cannot handle the amperage draw from the controller? I am not sure how to see what the bms inside this battery can handle. Since the sticker is blurred and worn out. But perhaps it is possible to open the battery and see if the battery has a bms of 45-50 somehow? Then if the controller pulls 50-52 amps perhaps it cuts out sometimes? Or am I thinking about the mechanism correct?

The thing that occurs is that the bike is running along fine and fast. But sometimes the current cuts out. This happens both with throttle and pedal assist. I have also gone over the connections and I think they are all solid.

The controller is a relatively strong one. I think the max current is around 52amps since the rated current is 26. I put a picture of the specs of this one below.
 

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Does power shut off completely? Or does the motor just stop driving, yet power remains on?

The former means the battery's BMS has shut off the output for whatever reason. The latter usually means the controller itself shutdown for whatever reason.

If it only happens when voltage drops under load, it's probably the LVC (of the BMS in the first place, and the controller in the second). If you don't know if voltage is dropping under load, you'll need to setup a voltmeter on the battery that you can see during testing and then watch it as you put the system thru load tests to cause the problem to happen, and then note down (or record a video of) the voltages you see.

The former may mean an actual problem with the battery, or just insufficient for the controller's demands. If you know the battery's specifications (peak amps, max amps, continuous amps) and the controller's battery current limit(s), you can easily see if it's just insufficient.

If it's not insufficient, you can try troubleshooting it, or just replace it. If it's just insufficient, you can either replace it or add another in parallel with it that can make up for the difference.
 
tomjasz said:
My apologies for this side track, but anyone that appreciates hand wound motors MUST see mountain girl Lin Guoer and her YouTube channel. Amazing…

https://youtu.be/mKWJnC9Ype8

I think she might've done this once or twice. ;)

She is definitely amazing to me. That motor might be better than when it was first built. :)
 
amberwolf said:
Does power shut off completely? Or does the motor just stop driving, yet power remains on?

The former means the battery's BMS has shut off the output for whatever reason. The latter usually means the controller itself shutdown for whatever reason.

It is the latter. It only happens now and then and the battery seems to be fine after the shutoff.

The bike keeps on going pretty strongly after. The battery or motor does not seem to be extra hot or anything like that.

So it only happens in small bursts. It just stops supplying current to the system. And then it keeps on going again.

Do you think this is the controller?

It is a new controller so it should be working I guess. It also came together with the motor so they are supposed to be in the same system.

The battery is the only thing that did not come with the kit, but it is also quite decent quality I think. Because it can handle a lot of riding without decharging too fast it seems. And it does not get very warm.
 
E-driver_ said:
It is the latter. It only happens now and then and the battery seems to be fine after the shutoff.

The bike keeps on going pretty strongly after. The battery or motor does not seem to be extra hot or anything like that.

So it only happens in small bursts. It just stops supplying current to the system. And then it keeps on going again.

Do you think this is the controller?
More details are required to guess reasonably.

Under exactly what circumstances does it happen? What circumstances does it *never* happen under? (if you go slow, does it happen? Does it happen if you go up a hill but not if you ride on the flats? Does it happen if....? )

So far all we have is
"The thing that occurs is that the bike is running along fine and fast. But sometimes the current cuts out. This happens both with throttle and pedal assist"
plus your new info above, which unfortunately doesn't tell us what speed you're going relative to it's max speed, what the load on the system is like (terrain, wind, etc), and so on, to see what might be contributing to the shutdown.

Also need to know if you see voltage sag when it is happening (and if so, is that *only* when it is happening, or also the same voltage sag at other times it does not happen). (does the battery meter drop when it happens--if the meter doesn't respond quickly or show anything, you may need to use a voltmeter attached to the handlebars where you can read it while riding, with it connected to the battery leads to the controller).

More detail is better. ;)
 
amberwolf said:
Also need to know if you see voltage sag when it is happening (and if so, is that *only* when it is happening, or also the same voltage sag at other times it does not happen). (does the battery meter drop when it happens--if the meter doesn't respond quickly or show anything, you may need to use a voltmeter attached to the handlebars where you can read it while riding, with it connected to the battery leads to the controller).

Hmm I will see if my extension cables are long enough to put the wattmeter on the steering rack. (Battery is located on the rear rack and the controller is on the top tube).

But if I understand it correctly I should connect the wattmeter going from the battery to the controller, right? Then tape it to the steering and watch it when I ride in different circumstances? Watching for dropping wattage when the weird burst-shut off arises?
 
E-driver_ said:
But if I understand it correctly I should connect the wattmeter going from the battery to the controller, right?
Yes. .

Then tape it to the steering and watch it when I ride in different circumstances?
Yes. Try things you think will cause the problem, and if it happens, note down what the meter says just before it does, and when it does, and after it does.


Watching for dropping wattage when the weird burst-shut off arises?
Voltage.

Voltage drop is what indicates a problem with the battery being unable to supply the demands the controller makes.
 
amberwolf said:
E-driver_ said:
But if I understand it correctly I should connect the wattmeter going from the battery to the controller, right?
Yes. .

Then tape it to the steering and watch it when I ride in different circumstances?
Yes. Try things you think will cause the problem, and if it happens, note down what the meter says just before it does, and when it does, and after it does.


Watching for dropping wattage when the weird burst-shut off arises?
Voltage.

Voltage drop is what indicates a problem with the battery being unable to supply the demands the controller makes.

I have one that looks like this. Picture and link.

Do you think that will do it?

https://www.aliexpress.com/item/1005003975079461.html?spm=a2g0o.productlist.0.0.130c5f60qe0L69&algo_pvid=aa48503c-e0ba-4153-aa31-1d2dd135ca93&algo_exp_id=aa48503c-e0ba-4153-aa31-1d2dd135ca93-20&pdp_ext_f=%7B%22sku_id%22%3A%2212000027613732969%22%7D&pdp_npi=2%40dis%21NOK%21226.56%2195.13%21%21%216.22%21%21%402100bdd516690686646043246e9953%2112000027613732969%21sea&curPageLogUid=oxxssE68XteZ
 

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E-driver_ said:
I have one that looks like this. Picture and link.

Do you think that will do it?
I got one of those years ago ... lasted about two weeks.
 
Hmm I think I found the problem. You know inside the battery rail where the two cables are soldered to the pins. It had begun to slowly loose its hold of the pin this cable. So I think that is why it was giving me random cutoffs. Today I tried it again and the battery kind of dies completely. So I checked the first cable from the battery rail and it was not giving voltage.

Now I have soldered the whole shabang on there again. And tomorrow I am going to testdrive again.

I also managed to make the bike fall when I wasn't very focused and it was standing beside me. So now I also have a destroyed front light and kickstand.

So the testdrive tomorrow will be for buying those two things :)
 
I tried the bike today and it seems to work fine for now.

Now, a weird thing happened going up a steep slope after I had been to the tool-store. The battery was around 30-50% left in the tank(I think because it is a little difficult to see on the sw900-display.

Now when I was riding on the highest gear and the highest level on the wattage the battery just died. Because of low charge I figured.

Now the bike had been standing in around 0 degrees for a good while before I rode home from the tool-store. Perhaps this could be a a cause for the rest of the story.

Now usually with another battery I have that is high quality I can wait a while and the battery recuperates. Now this battery which is 48volt17ah, seems to recuperate very slowly. Because it was showing red dot charge all the way home when I pressed the level button on the battery.

Now when I got home like 40 minutes later I took the battery inside for a while. And then I checked the level on my BBS02 where it is much easier to see the exact charge-level.

It showed 37%(!). I then tried it on the other bike again and it was now up and working again.

Any idea why this happened?

Could the battery get really "tired" from the cold. And then not wanting to take me up the slope and just shut down the charge?
But in that case why did it not recuperate again before like an hour later? Do some batteries recuperate charge much slower than others? Or would the cold make it kind of recharge itself much slower?

Or do you think it just became "too much" for the battery or something?
 
You've got a lot of variables that you mentioned, but the main one:

E-driver_ said:
Could the battery get really "tired" from the cold. And then not wanting to take me up the slope and just shut down the charge?
But in that case why did it not recuperate again before like an hour later? Do some batteries recuperate charge much slower than others? Or would the cold make it kind of recharge itself much slower?

Presumably you have heard about voltage sag. For most battery chemistries, cold temperatures will amplify it. Hazarding a guess, your battery's voltage sagged during a hard current draw, while it was already at 30-50% SOC, so the sag probably caused the controller or BMS to trigger LVC. You may not have had this happen at previous similar scenarios in warmer weather, because the battery was warmer, so the sag was not so drastic.

Did you charge the battery as soon as you got home? If so, you shouldn't have: it sounds like the battery was very cold, 0 degrees C, through and through. If you charged it right away, it could have caused some permanent damage.
 
harrisonpatm said:
You've got a lot of variables that you mentioned, but the main one:

E-driver_ said:
Could the battery get really "tired" from the cold. And then not wanting to take me up the slope and just shut down the charge?
But in that case why did it not recuperate again before like an hour later? Do some batteries recuperate charge much slower than others? Or would the cold make it kind of recharge itself much slower?

Presumably you have heard about voltage sag. For most battery chemistries, cold temperatures will amplify it. Hazarding a guess, your battery's voltage sagged during a hard current draw, while it was already at 30-50% SOC, so the sag probably caused the controller or BMS to trigger LVC. You may not have had this happen at previous similar scenarios in warmer weather, because the battery was warmer, so the sag was not so drastic.

Did you charge the battery as soon as you got home? If so, you shouldn't have: it sounds like the battery was very cold, 0 degrees C, through and through. If you charged it right away, it could have caused some permanent damage.

I waited a while actually. Before I charged it. It was not extremely cold outside where I left it. Around 0-3 degrees I think.

I have heard about voltage sag but I don't quite understand what it means. I only have a rough estimate in my head about what it is.

What is it more precisely?

This never happened to me with other batteries. Does the BMS play into this and is it possible to make it more voltage sag resistant somehow?
 
E-driver_ said:
harrisonpatm said:
You've got a lot of variables that you mentioned, but the main one:

E-driver_ said:
Could the battery get really "tired" from the cold. And then not wanting to take me up the slope and just shut down the charge?
But in that case why did it not recuperate again before like an hour later? Do some batteries recuperate charge much slower than others? Or would the cold make it kind of recharge itself much slower?

Presumably you have heard about voltage sag. For most battery chemistries, cold temperatures will amplify it. Hazarding a guess, your battery's voltage sagged during a hard current draw, while it was already at 30-50% SOC, so the sag probably caused the controller or BMS to trigger LVC. You may not have had this happen at previous similar scenarios in warmer weather, because the battery was warmer, so the sag was not so drastic.

Did you charge the battery as soon as you got home? If so, you shouldn't have: it sounds like the battery was very cold, 0 degrees C, through and through. If you charged it right away, it could have caused some permanent damage.

I waited a while actually. Before I charged it. It was not extremely cold outside where I left it. Around 0-3 degrees I think.

I have heard about voltage sag but I don't quite understand what it means. I only have a rough estimate in my head about what it is.

What is it more precisely?

There's lots of info online, try googling "voltage drop," that's a somewhat more common term. But briefly, and simplified, and narrowed to apply to ebikes: when you pull a lot of current from a battery, the nominal voltage of the battery will drop. Higher current draw means lower voltage sag. The extent to which the battery voltage drops depends on many factors, including battery quality, battery health, current, length of wire... Sometimes the sag can be so low as to make the motor controller think the battery is depleted, depending on the settings.

E-driver_ said:
This never happened to me with other batteries. Does the BMS play into this and is it possible to make it more voltage sag resistant somehow?
This does happen, with basically all batteries, in all uses. The extent to which is happens is what matters. Perhaps you have had excellent quality battery that never saw any sort of significant current draw. Or perhaps it has happened, but never so much as to trigger the controller's LVC. And again, the cold weather will increase the amount it occurs.
 
harrisonpatm said:
The extent to which the battery voltage drops depends on many factors, including battery quality, battery health, current, length of wire... Sometimes the sag can be so low as to make the motor controller think the battery is depleted, depending on the settings.

Hmm I do have quite a long wire on this one. Probably 60-65 centimeters from the battery rail to the controller. The reason is I have the battery mounted on the rack and the controller mounted on the top tube in front. Therefore it needs some length.

This might effect the voltage sag you think?
 
E-driver_ said:
Hmm I do have quite a long wire on this one. Probably 60-65 centimeters from the battery rail to the controller.
...
This might effect the voltage sag you think?
Only if it is 16 or 18 AWG wire.
Sound silly ??? Well that is what my NEW Bafang BBS02 has for power leads ....
I am going to have to crack the case open and change those out to 12 AWG.
 
LewTwo said:
E-driver_ said:
Hmm I do have quite a long wire on this one. Probably 60-65 centimeters from the battery rail to the controller.
...
This might effect the voltage sag you think?
Only if it is 16 or 18 AWG wire.
Sound silly ??? Well that is what my NEW Bafang BBS02 has for power leads ....
I am going to have to crack the case open and change those out to 12 AWG.

Hmm I don't know I could post a picture. 12 is the best or best to maybe go even lower?

Or perhaps go with xt90-cables might up the connection there perhaps? It is 48volt but perhaps good to go with xt90 anyway? I mean for thickness of wire and connectors.
 
Oh man! :)

I think they might be 14 these cables yes. I did not know what I was doing when I ordered these o I thought they were good :)

But lower is better then right so 12 or lower? 14 might be a bit thin? :)
 
E-driver_ said:
Oh man! :)

I think they might be 14 these cables yes. I did not know what I was doing when I ordered these o I thought they were good :)

But lower is better then right so 12 or lower? 14 might be a bit thin? :)
Lower is better (larger diameter = more copper, lower resistance) however there is a point of 'diminishing returns'. I use 12 AWG unless it is really a long distance (greater than 4 feet) but I rarely run more than 20 amps draw ... maybe 30 (at 52 volts) momentarily. See the attached spreadsheet.

Regards cold temperatures: Batteries are based on a chemical reactions. Most battery chemistries like temperatures in about the same range as humans (sans coats, sweaters, HVAC, etc). Colder temperatures slow down the reactions ... thus the battery can not produce as much power or recover as quickly. The exception is a battery under heavy current draw that might be close to overheating.

When I was working for my rich Uncle Sam in remote Alaska (decades ago) we always kept lead acid batteries on charge in the winter. Otherwise we might not get the vehicles to crank the engines until spring time.
 

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This chart says 14 gauge wire is suitable for 32 amps.
https://www.powerstream.com/Wire_Size.htm

I've used 14AWG pure copper wire for battery leads on speed controllers up to 35 amps, with no problems or noticeable warming of the wire runs. It's a rare circumstance when a controller draws its maximum power for a prolonged uninterrupted period. It's a safe bet that any one of your plugs is a much more significant bottleneck for current flow than 14ga wire is.
 
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