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Hmmmmmmmmmmm... is this bad? (some minor[?] ACM heat damage)


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What do you mean? Where the cables come out from the battery packs? A cabling visible in the board space is ok.

Also, I'm smelling nothing. The burnt sleeve part smells a bit burnt, but the rest of the wheel smells as it should.

Edited by meepmeepmayer
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2 minutes ago, meepmeepmayer said:

What do you mean? Where the cables come out from the battery packs? A cabling visible in thje board space is ok.

Nope...

i mean where the plus and minus terminals of the 18650 cells are sitting! GW uses cheap material to connect the 18650....

If much amps are drawn, this heat can come through...and even melt the heatshrink paper on the above and down the cells..

@zlymex postet a photo of that happening...

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On 07/10/2017 at 11:35 PM, zlymex said:

I don't use that cell cases for current over 1A, the reasons have been best described above. I got some of those cases as well which I use for testing 18650 cells at not over 2A current after I modified the wires.

I don't use spot welder neither when I build battery packs, even one of my friends got one readily accessible by me. Most of the common spot welders are low current rated thus cannot weld thick nickel strip.

Thick nickel strip is necessary because nickel is less conductive than copper(only about 25%), let alone there are nickel plated steel strips widely available with even less conductivity.

 Even professionals like Gotway(is it?) has not done this correctly, only about 0.1mm thickness is used for their EUCs, and I don't know the type(of nickel or nickel plated steel).

Here is the ACM(820Wh, two packs of 410Wh each) of one of my friends, the nickel strip was once(or several times) becoming so hot that burned the shrink wrap through a fish paper layer.
596445a6de6f4_webwxgetmsgimg(24)sp.jpg.d5bc8b326a4ef41777c0d6ce6383532c.jpg

Guys check your batteries if you are hill lovers, that is another hazard apart from motor wires and motor connectors

 So what and why do I use when I build my own battery pack? I won't talk about it this time because I don't recommend to others.

Here....

More pictures in the thread. I'd certainly have a look. As for the connector...it looks like it has melted quite a bit. It will not stop doing it unless you stop your wonderful (but stressful to the wheel) rides. I say remedy now rather than reassemble and hope for the best. @Marty Backe  removed the connectors and soldered the wires together I think. Maybe this should be an option for you too. Eventually it will melt enough to short something else. Then you are stranded and have a bigger repair bill to deal with.

Edited by WARPed1701D
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40 minutes ago, KingSong69 said:

Nope...

i mean where the plus and minus terminals of the 18650 cells are sitting! GW uses cheap material to connect the 18650....

If much amps are drawn, this heat can come through...and even melt the heatshrink paper on the above and down the cells..

@zlymex postet a photo of that happening...

I had a close look at the battery (only board side) and it looks great. Found and repaired a little spot where a screw had damaged the plastic cover, though.

I really believe that one connector is the only damaged spot. All the usual suspects are ok - where the motor cables and hall sensor wires come out from the big sleeve, the motor wires, the other connectors, everything perfectly fine.

I really wonder how this specific damage happened. Long, strong current, or shorter but very strong current? (had a short very steep part) Why are the other connectors ok? Is it really only that sleeve that did this somehow? Even the motor cables in the sleeve next to the connector are perfectly fine. Maybe the connector is failing?

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15 minutes ago, WARPed1701D said:

Here....

More pictures in the thread. I'd certainly have a look. As for the connector...it looks like it has melted quite a bit. It will not stop doing it unless you stop your wonderful (but stressful to the wheel) rides. I say remedy now rather than reassemble and hope for the best. @Marty Backe  removed the connectors and soldered the wires together I think. Maybe this should be an option for you too. Eventually it will melt enough to short something else. Then you are stranded and have a bigger repair bill to deal with.

Thanks!!!!:clap3:

In the photos it looks worse than in real life.

Problem is, I have no soldering or other equipment (and experience) whatsoever, but I guess I'll have to have a look at the connector now.:crying:Possibly another mountain ride planned for Monday, with @Tilmann (if time works out), can't have it failing then.

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4 minutes ago, meepmeepmayer said:

Thanks!!!!:clap3:

In the photos it looks worse than in real life.

Problem is, I have no soldering or other equipment (and experience) whatsoever, but I guess I'll have to have a look at the connector now.:crying:Possibly another mountain ride planned for Monday, with @Tilmann (if time works out), can't have it failing then.

You've done several heavy rides with this unit so far and the connector has reached that state. I doubt one more will be the tipping point to failure especially if it is less stressful than some of the others you have posted so I wouldn't rush the repair before you are ready, but I would do it sooner rather than later. You could always stop by an electrical repair shop and ask if they would do the work for you. Replacing the connector could be done by anyone with some soldering experience regardless of what they usually repair.

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I'll manage, some friends with more electrical experience do exist. The real number of (noteworthy for the stress/currents) mountain rides is like 4, so it's not extreme. But maybe it indeed is not from the last ride (although that's my guess, I just want to know from which part).

I'll think about it (but not for too long, next week it must be done if repaired now). Thanks, man:)

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1 minute ago, Marty Backe said:

Yep, your cables are melting like mine did, just not long enough to cause them to short together.

Are they? They certainly would have after more stress, but for now only the one connector is damaged (the others look perfect, but they also did when my cables melted together, so it means nothing).

What really bugs me is why one connector is damaged and the others not. That tiny bit of sleeve certainly can't have made the difference alone. But it literally only started melting where it touched the sleeve, and only there. WHY???:unsure:

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41 minutes ago, meepmeepmayer said:

Are they? They certainly would have after more stress, but for now only the one connector is damaged (the others look perfect, but they also did when my cables melted together, so it means nothing).

What really bugs me is why one connector is damaged and the others not. That tiny bit of sleeve certainly can't have made the difference alone. But it literally only started melting where it touched the sleeve, and only there. WHY???:unsure:

In my case the three connectors were laying side-by-side, so they melted together. Maybe only one of the connectors got super hot like yours, but since it was touching the other connector they jointed into one. In my case the connectors did not short, but the wires did. This is why I focus on keeping the wires separated so that even if they get hot enough to melt the insulation, they can't touch.

Maybe don't focus on 'Why', but instead prevent the melting from causing any problems. We might not like it, but that's reality. Of course this is only necessary if you're worried about it. Just take longer breaks in the future and shorter hill climbs - if you're not going to fix anything inside the wheel.

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1 hour ago, meepmeepmayer said:

I had a close look at the battery (only board side) and it looks great. Found and repaired a little spot where a screw had damaged the plastic cover, though.

I really believe that one connector is the only damaged spot. All the usual suspects are ok - where the motor cables and hall sensor wires come out from the big sleeve, the motor wires, the other connectors, everything perfectly fine.

I really wonder how this specific damage happened. Long, strong current, or shorter but very strong current? (had a short very steep part) Why are the other connectors ok? Is it really only that sleeve that did this somehow? Even the motor cables in the sleeve next to the connector are perfectly fine. Maybe the connector is failing?

I dont know how this motor drivers work ...but i would guess one cable is for responsible for powering for accelarating and one for braking and one ...?

so for me it makes sense that one is more damaged than the others...

 

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5 minutes ago, esaj said:

My best guess is that the one that has began to melt has poorer connection than the others (higher resistance) and heats up more/faster than the rest under high currents.

Yea, this kind of suggests itself. Guess I'll have to re-do the stupid thing. FFFFFFFUUUUUUUUUUUU... oh well, such is EUC life.

--

What do I need to solder the wires together directly? Soldering iron and some kind of high-temperature solder? Heatshrink tubing? Anything else? besides lots and lots of cable ties:-) Where to get this quickly? :)

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I like the cable tie idea and thought it was to increase breathability of a hot cable in an attempt to prevent it from reaching a point of melting insulation or to stop two hot cables that are touching each other from melting due to combined heat. But @Marty Backe  suggests it is to keep two melted and exposed wires seperated. Surely if a wire is hot enough to destroy its insulation it will be hot enough to destroy a cable tie too especially as it is more likely to fail at the point a cable tie is wrapped around it and thus heat insulating it. Would there not be a better material to use if this is the case other than a cable tie?

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13 minutes ago, WARPed1701D said:

But @Marty Backe  suggests it is to keep two melted and exposed wires seperated. Surely if a wire is hot enough to destroy its insulation it will be hot enough to destroy a cable tie too especially as it is more likely to fail at the point a cable tie is wrapped around it and thus heat insulating it. Would there not be a better material to use if this is the case other than a cable tie?

It's also for keeping the insulated wires separated - all known insulation failures happened where two or more cables touched. Maybe that stupid tubing really did cause that specific connector to melt, so who knows.

But it really is mostly for keeping potentially exposed wires apart. These melting spots aren't too big, and even if one tie fails, the others next to it might be enough. Or one cable is interrupted before two of them touch.

This is only an emergency measure after all, you stilll have to be careful not to have too much current for too long. I find what Marty did is the natural thing to do.

Edited by meepmeepmayer
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10 minutes ago, esaj said:

Heatshrink/silicone-tubing or even just electric tape if you can't find anything else for covering the contacts is a good idea, you don't want them getting in touch with each other, otherwise the motor will lock up (very strong braking) and at the same time likely fuse the wires together. If the joint is good, it shouldn't heat up much more than the cables in general, so probably not that critical to get very high temperature solder like those with very high lead-content or that Au/Sn (gold/tin) -stuff that likely costs a small fortune and isn't readily available anyway. And if the entire cables then start to melt... well, you've got a whole new problem ;)

Maybe it would make sense to have these new connections as weak points. Better than cables fusing together in the depths of the big motor wires sleeve. Hmm...

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5 minutes ago, meepmeepmayer said:

It's also for keeping the insulated wires separated - all known insulation failures happened where two or more cables touched. Maybe that stupid tubing really did cause that specific connector to melt, so who knows.

But it really is mostly for keeping potentially exposed wires apart. These melting spots aren't too big, and even if one tie fails, the others next to it might be enough. This is only an emergency measure after all, you stilll have to be careful not to have too much current for too long. I find what Marty did is the natural thing to do.

I think the sheath was probably the last straw for the hot connector tipping it to the point of melting. A bit like wrapping it in a duvet. The others may have done the same if they had been touching each other or something else.

Using ties to keep wires apart and increase their ability to radiate heat and prevent an incident in the first place makes sense as long as the tie itself doesn't cause a hot point where it wraps the wire. I just wasn't sure of their ultimte utility in keeping a failed wire from eventually touching something else. If that were the intention of their installation then I may have been looking for a different solution.

From what I have read though the wire insulation has never shown signs of melting, even in the crowded space of the axle, so the high resistance of improperly speced connectors is likely the main weak point, and you are about to deal with that.

9 minutes ago, meepmeepmayer said:

Maybe it would make sense to have these new connections as weak points. Better than cables fusing together in the depths of the big motor wires sleeve. Hmm...

Then they should have used fuses! :lol:

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