meepmeepmayer Posted August 10, 2017 Share Posted August 10, 2017 After my latest, quite demanding mountain ride (and planning more), I figured it would be a good time to check the insides of my 84V ACM. Aaaand there's some bit of heat damage on one of the motor connectors! Here's how it looks, if you have some input how severe it is (probably ok, but who knows) and if that connector needs to be redone, or what else is recommended, I'd be very grateful. Except for that one issue, everything is perfectly ok with no visible damages whatsoever. #1 Overview. You can see a bit of damage at the one motor connector covered partially by that heat sleeve. #2 Closer look. The discoloring on the sleeved cables is normal, that's just how they are colored. There is no visible damage anywhere, except for the one connector. #3-5: The sleeve is lightly stuck to the connector, and the connector itself is a bit heat-damaged. The other cables in the sleeve are totally fine. All the cables coming from the black motor sleeve are totally fine. #6-7: Cut out that part. Funnily enough, the inside looks less bad. #8-11: A closer look at the connector. The upper side (where the sleeve was) shows heat damage, the rest of the connector is ok (it looks much worse in those close-up, flash photos than it is). Well, guys, be careful on mountains If you have any input, specifically whether this is ok and can be left as is, or whether the connector should be redone... Is there some kind of high-temperature duct tape to reinforce certain parts, if necessary? How bad is this? Link to comment Share on other sites More sharing options...
US69 Posted August 10, 2017 Share Posted August 10, 2017 Just for interest: Have you checked the upper and lower parts of the batterie? As there have been reports of burned batterie connectors, which even come through the heatshrink... Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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. Link to comment Share on other sites More sharing options...
US69 Posted August 10, 2017 Share Posted August 10, 2017 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... Link to comment Share on other sites More sharing options...
WARPed1701D Posted August 10, 2017 Share Posted August 10, 2017 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. 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. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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? Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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!!!! 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.Possibly another mountain ride planned for Monday, with @Tilmann (if time works out), can't have it failing then. Link to comment Share on other sites More sharing options...
WARPed1701D Posted August 10, 2017 Share Posted August 10, 2017 4 minutes ago, meepmeepmayer said: Thanks!!!! 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.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. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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 Link to comment Share on other sites More sharing options...
Marty Backe Posted August 10, 2017 Share Posted August 10, 2017 Yep, your cables are melting like mine did, just not long enough to cause them to short together. I removed my connectors and soldered the wires together. I then added separators to keep all of the wires from touching each other. I recently opened my ACM again and everything looks perfect. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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??? Link to comment Share on other sites More sharing options...
Marty Backe Posted August 10, 2017 Share Posted August 10, 2017 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??? 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. Link to comment Share on other sites More sharing options...
US69 Posted August 10, 2017 Share Posted August 10, 2017 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... Link to comment Share on other sites More sharing options...
esaj Posted August 10, 2017 Share Posted August 10, 2017 12 minutes ago, KingSong69 said: 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... Nope, all the cables are in use while motoring or braking. 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. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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? Link to comment Share on other sites More sharing options...
esaj Posted August 10, 2017 Share Posted August 10, 2017 Just now, meepmeepmayer said: 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? Probably almost any decent hardware store carries pretty much all you need. A very basic soldering iron with no temperature control is probably good enough for this, if you have no further use for it, and shouldn't cost much (I've seen some basic 40-80W irons for <10€ here). Many alloys in soldering wires have high melting temperatures, such would probably be good for this (something like Sn/Ag = tin/silver or Sn/Sb = tin/antimony for example). Here's some generic table of ratios and melting points I grabbed from Google Image search (but there are many more alloys): 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 Link to comment Share on other sites More sharing options...
WARPed1701D Posted August 10, 2017 Share Posted August 10, 2017 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? Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 @esaj Wow thanks, will try to find this stuff tomorrow. Soldering iron (might already be available) Soldering wire. Heatshrink tubing (thanks for the keywords/tip with the electrical tape, some duct tape that can take temperatures might always be useful) That's it? Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 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... Link to comment Share on other sites More sharing options...
WARPed1701D Posted August 10, 2017 Share Posted August 10, 2017 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! Link to comment Share on other sites More sharing options...
esaj Posted August 10, 2017 Share Posted August 10, 2017 20 minutes ago, meepmeepmayer said: @esaj Wow thanks, will try to find this stuff tomorrow. Soldering iron (might already be available) Soldering wire. Heatshrink tubing (thanks for the keywords/tip with the electrical tape, some duct tape that can take temperatures might always be useful) That's it? Pretty much... a couple of items that might become useful are something like: Something to remove the sheathings from the wires... knife might do, just be careful not to nick (too many) strands inside the wires A good quality wire stripper is expensive though. There are some cheapo "automatic" wire strippers that work well enough for most stuff, look about like this: Then either a soldering "helping hands" or just a couple of books on either side might work to keep the wires in place (they should not move about while you solder them): If you're using heatshrink or silicone tubing, remember to slide it into one of the cables before you put them together Braid the wires together as tight and as well as you can (there are multiple techniques, I won't go into debating what is best): and have them held (by the helping hands or books or other weights or whatever) so they're not being pulled. Put a little bit of tin on your soldering iron tip, take it to the braid and let it heat up a few seconds, apply more solder while keeping the iron there (the wires should wick the solder up), then remove the iron and let the joint cool down before taking it off from whatever's holding the cables, then insulate it somehow (heatshring/tape...). Don't go overboard with the solder amount, it won't help that much to have a huge blob on the joint and it will just prevent you from seeing the joint well as well as start to wick inside the insulation. To my (untrained) eye, something like this looks like a proper joint, you can still see the shape of the strands in the joint, but it looks shiny and smooth: If you need better instructions, there's probably loads of tutorials and videos up in the internet. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted August 10, 2017 Share Posted August 10, 2017 That's a pretty decent char on that insulator sleeve. I wonder if it was due to the insulator touching the outer shell which reflected the heat back so the outside was darkened. The other black plastic connectors are more air cooled rather than sitting against the insulation tubing and the shell so they don't heat up as much. You could get some of these butt connectors and a crimping tool: https://www.cableorganizer.com/multilink-butt-splices/#features I think it's generally a good idea to keep the high voltage motor cable separate from each other and apart from the low voltage hall sensor wiring as we know that the high voltage wiring does tend to heat up quite a bit. At connection junctions where the metal connectors may not be equally as conductive as the wire itself, that extra resistance translates to heat given off which can be enough to melt solder and the black plastic covers. Link to comment Share on other sites More sharing options...
Pard Posted August 10, 2017 Share Posted August 10, 2017 2 hours 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??? Heat builds up at the connector, and not at some random spot along the wiring, due to resistance from the joint. The soldering of the wire to the connector plug could have been done poorly (I bet it was) or the connector itself could be poorly fitting or corroded to some degree. The other connectors and solder joints most likely had less resistance. If you have the unit open already, it makes sense to do what Marty did and solder the motor wires directly to the board extensions. This is not a joint you will be frequently disassembling, so make the connection as resistance free as possible by joining the two wires and protecting with a sleeve. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted August 10, 2017 Author Share Posted August 10, 2017 23 minutes ago, Hunka Hunka Burning Love said: That's a pretty decent char on that insulator sleeve. I wonder if it was due to the insulator touching the outer shell which reflected the heat back so the outside was darkened. The other black plastic connectors are more air cooled rather than sitting against the insulation tubing and the shell so things heat up more. Wow, you're a smarty Indeed right. There's a small imprint of the connector on the side pad (but where it directly touched, not where the sleeve was between them, just a little discoloring there. Didn't see it before (it looks much worse in the photo than it is, again). Can't believe something like this can make a difference. Must have been closer to disaster that I thought. 23 minutes ago, Hunka Hunka Burning Love said: I think it's generally a good idea to keep the high voltage motor cable separate from each other and apart from the low voltage hall sensor wiring as we know that the high voltage wiring does tend to heat up quite a bit. That's exactly how they installed it, the hall and motor wires have separate routing as soon as they exit the big sleeve. Link to comment Share on other sites More sharing options...
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