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

[Pard]

1 hour ago, esaj said:

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.

What he said ...

[meepmeepmayer]

7 minutes ago, Pard said:

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.

Ha, you'll probably win this one

I'm actually glad they fucked up the connector. Better this now than melted cables again (my connectors were fine back then, even though they were the sketchy old ones that frequently failed, while the cables shorted together through the insulation).

Ideally this could be repeated. There should be some fuses you can put in the wires that start whining when they get too hot or something like this, to warn you.

[WARPed1701D]

17 minutes ago, Pard said:

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.

Maybe the GotWay glue gun specialist built your EUC and opted to forgo solder on that connector and just glued it!  (See @Marty Backe thread about his Charging connector).

[esaj]

18 minutes ago, meepmeepmayer said:

Ideally this could be repeated. There should be some fuses you can put in the wires that start whining when they get too hot or something like this, to warn you.

I don't know if fuses that warn you about getting near the limits exist, but that's actually a pretty good idea (assuming that the wheel itself has no warning of using "too much" power over extended periods). Ideally, a current sense -IC & some extra electronics (or a microcontroller) could be used for a warning system, but even the motor current sensor-ICs (ACS7xx, don't remember the specific model) on Rehab1's ACM-board he sent to me are partially bypassed with very small resistors (1 milliohm, if memory serves, and then likely compensated for in software), probably because they cannot handle the high current by themselves. I think @zlymex used some form of inductive current measurement (I'm not sure what they are called in English, just "inductive current sensors"?) that are touch-free and won't add resistance in the measured circuit:

 

 

That's probably physically way too large though   But with similar (smaller) sensor, a single motor phase could be monitored, and if "too high" (how ever much that is) averaged current is measured over some certain amount of time (1 second or whatever), the thing could start beeping...

[Hunka Hunka Burning Love]

1 hour ago, meepmeepmayer said:

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.

That's exactly how they installed it, the hall and motor wires have separate routing as soon as they exit the big sleeve.

  I must have watched too many episodes of 

If your connectors are crimped, you could just do like what Marty did and separate them all.  You might not need to replace them?  You could add on a heat shrink tube over the connectors to give them some added protection, but they do have their melting limits.  Maybe some TechFlex insulation tubing might help along with keeping the motor wires separate and not touching anything near the connectors.

[Marty Backe]

1 hour ago, esaj said:

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.

 

 

 

Very good info @esaj. FYI, I opted to join my wires per diagram #5. I used generic solder and obviously went with heat shrink tubing.

These wires don't get hot enough that the insulation drips off the wire  so I'm really not worried about my cable ties melting too. I probably went a bit overboard with my excessive use of cable-ties, but I figured it can't hurt. In my opinion what's important is to keep the wires separate from each other a couple of inches on either side of the connectors. It's the connector region which is getting all of the heat. And I suspect when the connectors are eliminated the hot spots are also eliminated.

 

[Marty Backe]

2 hours ago, WARPed1701D said:

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.

Then they should have used fuses!

When I burned up my motor and control board it was because the wire insulation melted and the wires shorted together. The connectors melted together also, but they did not actually short. Everything within a few inches of either side of the connector are at risk of melting.

[Hunka Hunka Burning Love]

2 hours ago, esaj said:

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:

 

 

I have this one, and it's really bad.  It's supposed to be an automatic wire stripper, but it just doesn't grip onto the wire very well or at least mine doesn't  I got the cheapest of the cheapest so I'm paying for it twice as I don't even use it any more.  Maybe there are higher quality versions of this one, but really it's better to get the heavier duty wire stripper and be done with it as I think it also can crimp whereas the one above doesn't do that.

[Pard]

This reported failure had me worried, so I opened up my Msuper to check it out.

The connectors on mine are the newer versions in the clear shrink.  The solder connections from wire to connector seem robust.  No signs of any problems.

The screws that fasten the shell panel to the "frame" easily strip the soft plastic.  I use a drop of CA glue on each screw before I turn them in, so that they do not loosen up and disappear.

They are still easily removed with that drop of CA, but they will remain locked in place until I want them removed.

Additionally, the double sided foam tape on the battery that helps secure it to the shell is weakened every time you open it up.  Just remove a new strip of paper to expose fresh adhesive before closing up the shell.

[esaj]

42 minutes ago, Marty Backe said:

Very good info @esaj. FYI, I opted to join my wires per diagram #5. I used generic solder and obviously went with heat shrink tubing.

These wires don't get hot enough that the insulation drips off the wire  so I'm really not worried about my cable ties melting too. I probably went a bit overboard with my excessive use of cable-ties, but I figured it can't hurt. In my opinion what's important is to keep the wires separate from each other a couple of inches on either side of the connectors. It's the connector region which is getting all of the heat. And I suspect when the connectors are eliminated the hot spots are also eliminated.

Yeah, even eutectic tin/lead -solder (melting point around 183 Celsius) probably works just fine, as the joint shouldn't heat up in use that much if done properly (if you overlap the strands enough and there's a good connection, the joint might actually have even slightly lower resistance than other parts of the wire ). But using higher temperature solder can't hurt either (assuming the iron's hot enough to properly heat up and connect everything together).

I just watched the video @Pard linked earlier, good tips and a well made joint, although since I like to nitpick , I have to mention that when he goes over the solder types, he calls the last one "silver solder" (but later on corrects that it's "metal working silver solder"). The non-leaded electrical solder he shows in the middle also contains silver (most lead-free electrical solders are tin/silver in varying ratios), the issue with the first solder he discards is that it's for metal working and has acid core, the silver itself is not the problem. Also, I had totally forgotten that soldering guns exist (mostly I've heard them called "quick soldering irons"), probably works fine for this type of soldering, but for electronics, total crap (that's why I've forgotten that they exist ). The tip is way too big for any precision work, and while they really do heat up fast (thus "quick soldering irons", usually with powers exceeding 100W and no temperature control), they also very easily overheat and kill more heat-sensitive components like transistors. But if @meepmeepmayer is only planning to use it for soldering wires and such, then it's also an option. Do the connections like he shows in the video and you can't go wrong.

[esaj]

11 minutes ago, Hunka Hunka Burning Love said:

I have this one, and it's really bad.  It's supposed to be an automatic wire stripper, but it just doesn't grip onto the wire very well or at least mine doesn't  I got the cheapest of the cheapest so I'm paying for it twice as I don't even use it any more.  Maybe there are higher quality versions of this one, but really it's better to get the heavier duty wire stripper and be done with it as I think it also can crimp whereas the one above doesn't do that.

The one I have has a small screw you turn at the other side of the strippers to control the grip (turn it too tight, and it will nick the strands though, too loose and it does what yours does, and the adjustment is pretty touch'n'go ). But the funny thing is that those are usually much cheaper than proper "manual" strippers. In this case, if it's for just for this single use, even knife could work, if done carefully (cut only part way through the sheathing around the wire, not all the way to the strands, then lightly bend the cut part around and pull the sheathing off), but if there's need to strip wires more often, proper wire strippers will save you a lot of headache in the long run

Where I mostly use the "automatic" strippers is when stripping ribbon cables, as they can strip multiple wires in one go:

 

 

 

[Marty Backe]

53 minutes ago, Hunka Hunka Burning Love said:

I have this one, and it's really bad.  It's supposed to be an automatic wire stripper, but it just doesn't grip onto the wire very well or at least mine doesn't  I got the cheapest of the cheapest so I'm paying for it twice as I don't even use it any more.  Maybe there are higher quality versions of this one, but really it's better to get the heavier duty wire stripper and be done with it as I think it also can crimp whereas the one above doesn't do that.

I use this type. I have two for covering the entire range of wire sizes. They work great because skill is removed from the wire stripping operation. You can't make a mistake and get perfect results every time. Not the cheapest though.

[Hunka Hunka Burning Love]

 That's the Mercedes Benz of wire strippers.  Nice if you do a lot of electrical work, but a basic one for simple repairs works okay.  A pair of sharp needle point scissors also works in a pinch.

[Rehab1]

Ugh! @meepmeepmayer I was sure this was a past problem. Good thing you were prudent and looked inside.

I experimented with those factory GW heat sleeves and they melted at 95 degrees C. I feel very confortable with Marty's modification or if you don't prefer using wire ties as separators I like the heat sleeves I used. They would not melt when I used a blow torch at 1900 degrees C. 

 

If you are into soldering use 5mm bullet connectors. They are rated @ 150 amps each and you can still disconnect the motor wires if needed. 

 

[meepmeepmayer]

4 minutes ago, Rehab1 said:

Ugh! @meepmeepmayer I was sure this was a past problem.

This has nothing to do with the old, failing connectors. This new one is going to be crimped anyways.

The heat damage on the connector just shows the cable insulation would have failed not too far after this happened. Which is a known issue (me, Marty, @zlymex, ...) that was never actually fixed (they'd have to use vastly thicker cables for that and make new motors with bigger axles - aka design new wheels - all they did was using 14AWG on newer motors instead of 16AWG like on older motors like mine).

7 minutes ago, Rehab1 said:

I experimented with those factory GW heat sleeves and they melted at 95 degrees C.

Nice, a concrete number!

[MaxLinux]

8 hours ago, meepmeepmayer said:

#8-11: A closer look at the connector.

The plastic softened enough to be imprinted with the weave pattern of the sleeve! That must have been VERY hot!

[Paddylaz]

9 hours ago, meepmeepmayer said:

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.

 

So....should EVERYONE take a look at the insides of their euc every few weeks/months? Or is there an inherent 'fragility' to the Gotway electronics? 

I mean, when you say a demanding ride, presumably if the Gotway 'let's' you do it in the first place without a cut-out, doesn't that mean it's within normal safety parameters? Or not?

(apologies..... I have the electrical knowledge of a grapefruit).

[Marty Backe]

58 minutes ago, Rehab1 said:

Ugh! @meepmeepmayer I was sure this was a past problem. Good thing you were prudent and looked inside.

I experimented with those factory GW heat sleeves and they melted at 95 degrees C. I feel very confortable with Marty's modification or if you don't prefer using wire ties as separators I like the heat sleeves I used. They would not melt when I used a blow torch at 1900 degrees C. 

If you are into soldering use 5mm bullet connectors. They are rated @ 150 amps each and you can still disconnect the motor wires if needed. 

Any self-respecting hacker would have taken it to the nice round number of 2000 degrees c.   1900 degrees! That doesn't prove a thing.

[Marty Backe]

26 minutes ago, Paddylaz said:

So....should EVERYONE take a look at the insides of their euc every few weeks/months? Or is there an inherent 'fragility' to the Gotway electronics? 

I mean, when you say a demanding ride, presumably if the Gotway 'let's' you do it in the first place without a cut-out, doesn't that mean it's within normal safety parameters? Or not?

(apologies..... I have the electrical knowledge of a grapefruit).

Only if you ride long duration's (> 10 minutes?) up very steep hills.

I've even contemplated adding a clear Plexiglas window on the side so that you can peer inside the wheel with a flashlight. Then I would publicize the crap out of my modded wheel. Perhaps that would shame Gotway into making some changes 

[Pard]

35 minutes ago, Paddylaz said:

So....should EVERYONE take a look at the insides of their euc every few weeks/months? Or is there an inherent 'fragility' to the Gotway electronics? 

I mean, when you say a demanding ride, presumably if the Gotway 'let's' you do it in the first place without a cut-out, doesn't that mean it's within normal safety parameters? Or not?

(apologies..... I have the electrical knowledge of a grapefruit).

Yes.  It should be a scheduled maintenance item, every certain number of miles.

You can remove the pedals and side plates in a matter of minutes to inspect the condition of your axle bolt tightness, your motor connectors, etc.

The components are known to be hobby grade and prone to failure.  The wheel is subjected to constant jolts and vibration.  Inspection makes sense.

Alternatively, you can wait for them to fail.  

[Rehab1]

1 hour ago, Marty Backe said:

Only if you ride long duration's (> 10 minutes?) up very steep hills.

I'll test your  >10 minutes steep hill theory tomorrow on the ACM if it does not rain. I have 2 hours rented at the proving grounds . 

[Rehab1]

1 hour ago, meepmeepmayer said:

This has nothing to do with the old, failing connectors. This new one is going to be crimped anyways.

I forgot that you have the 16 awg wired motor. 

[Hunka Hunka Burning Love]

1 hour ago, Marty Backe said:

Only if you ride long duration's (> 10 minutes?) up very steep hills.

I've even contemplated adding a clear Plexiglas window on the side so that you can peer inside the wheel with a flashlight. Then I would publicize the crap out of my modded wheel. Perhaps that would shame Gotway into making some changes 

 Considering that the ACM already looks like a PC case on a wheel, adding in a clear window would be perfect!  Add in some sound activated lighting and away you go!

 

[MaxLinux]

5 hours ago, Hunka Hunka Burning Love said:

I have this one, and it's really bad.  It's supposed to be an automatic wire stripper, but it just doesn't grip onto the wire very well or at least mine doesn't  I got the cheapest of the cheapest so I'm paying for it twice as I don't even use it any more.  Maybe there are higher quality versions of this one, but really it's better to get the heavier duty wire stripper and be done with it as I think it also can crimp whereas the one above doesn't do that.

I have this kind too, and I love mine (I'm sure many variations and quality levels exist). 20 years ago at a computer show I got one of these for $5.00, totally expecting it to be junk. 20 years later it perfectly strips everything from the tiniest, thinnest wire to maybe 16 awg or so. It strips standed wires without cutting or nicking any of the strands. I marvel every time I use it that it was so cheap and works so well and lasted this long!!

[MaxLinux]

3 hours ago, meepmeepmayer said:

a known issue (me, Marty, @zlymex, ...) that was never actually fixed (they'd have to use vastly thicker cables for that and make new motors with bigger axles - aka design new wheels

I think this is the key to progress for the next generation of EUCs. What can be achieved with the current motors/axles has reached its maximum.