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[one more GOTWAY WARNING] ACM died on a hill (it was bad cabling + high stress, final update pg 16)


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So the motor cable is 3x1.5mm2 (around 16+ AWG)  + 5x0,2mm2 (for hall sensors). (found a video that shows it)

58cfdd19a5d75_Motorcable.jpg.544c3a6db811343cdc7dd97543d77084.jpg

So lets assume that the motor cable is made from silicon with a max temp of 200 degrees (thats insanely hot and should only be the result of a short and never under normal circumstances) Lets assume a high 125 degrees C for speculation

Looking at this http://catalog.connectronicscorp.com/Asset/WIREMAX-conductor-CURRENT--2-.pdf

The maximum current of a 16AWG is 26A at ambient 30C, but thats 1 cable i free air (not inside a box with heatgenerating mosfets) and the cable is now 125C! = Hot!

Combining 3 16AWG cables you get a factor of 0,8: 26*0,8 = 20.8A and thats in free air not inside a hot casing 26A = 200 degrees = failure.

 

So then for design purposes lets say max output is 2500W / 84V = 30A  then 40 * 0,8 (not free air) = 32A = 40A cable for design.

According to the Wiremax table then we need 14AWG = 2mm2 cable = and this is 30 degrees ambient (a hot sunny day and a black wheel and big hills and overheat protection at 80 degrees well, then you need to design cables for that situation so this is for some situations to small for my liking)

Me i would design around 90 degrees, so a 12AWG = 3,3mm2 cable almost double in whats installed today to be perfectly safe.

 

* Disclamer

The motor cable might not be made from silicon so then we need even bigger cables.

The load might be somewhat devided along the 3 motor cables / don't know DC engines enough, i only know 3-phase design and there the situation is different.

There are many other things to consider in the design but if you have design the wheel to constantly use maximum power then you need big cables.

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2 hours ago, Rehab1 said:

Interesting the motor wires are 16 gage.

Are you sure? From the pictures in the thread it looks like 3x1.0mm2 (17AWG)  cables to the motor from the markings on the motor cable.

*Wrong, found video, its 1,5mm2 = 16+ AWG.

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45 minutes ago, Xima Lhotz said:

Are you sure? From the pictures in the thread it looks like 3x1.0mm2 (17AWG)  cables to the motor from the markings on the motor cable.

They may be 17 AWG which is even worse!

I took 2 shorts videos of the so called 'Protective Heat Sleeve'. The sleeve is definitely not designed for high temperature which is troubling! 

In the first video I am cutting away the large protective sleeve covering the 3 motor wires to perform a flame test.. The 2nd video speaks volumes of the test!

 

 

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19 minutes ago, Rehab1 said:

They may be 17 AWG which is even worse!

All the info can be found on the motor cable something like: "3x1.0mm + 5x0,2mm2"

If it is 1.0mm2 then = 17AWG.

*Its 1,5mm2 = 16+ AWG, found a video that shows the correct information.

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14 hours ago, steve454 said:

They all say a certain slope is possible, but none of them say for how much time you can climb a hill before overheating.  They never say anything about overheating.  They should put some safeguard in the wheel to prevent overheating.  And like you said, not just better heatshields, but some kind of warning like beeps or slowing down like Kingsong does.  Several people mentioned their Kingsongs overheating and making it impossible to ride without a few minutes to cool down.  Annoying, but good safety feature.  Also just remembered a Speedyfeet video where he was climbing a long hill and the Ninebot went into low power mode until it cooled down.

When I overheated my ACM,I was climbing fire access roads in the foothills above my house.The ambient temp was 75F and I ascended hills with constant 20 to 30 degree grades for about a mile before it overheated.This was done on My modded ACM 2040 which has 3X the original battery wh capacity of 680wh for a total of 2040 wh.The wheel itself weighs 57lbs. and my weight is 200lbs.A 257lb. load for these conditions is a very well designed wheel in extreme conditions.When the wheel reached 79C it went into tilt mode and beeped just like when I overheated my KS14C except it (the 14C) shuts down at 69C.After my ride I inspected the motor connectors and there was no sign of overcurrent at the connectors due to faulty connectors but obviously many connectors are faulty and seemingly are the weak link(s) in these machines.The next mod for the ACM2040 will be the deletion of the motor connectors altogether.They are used for ease of assembly and really aren't needed by the end user so if anyone has concerns about the weaknesses of a Gotway,that is the mod that would I would recommend for peace of mind.

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38 minutes ago, jrkline said:

so if anyone has concerns about the weaknesses of a Gotway,that is the mod that would I would recommend for peace of mind.

There is another mod I just thought of for anyone looking for a little "gotway peace of mind". Stencil "Gotway" on your helmut,(if you have one).This is what @Marty Backedid and he has owned 3 ACM's; including my ACM before it became the world famous ACM2040,a Monster and Msuper v3 and has never had any motor connector problems.Obviously @Marty Backehas the blessings of the "Gotway Gods!":)

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11 minutes ago, jrkline said:

There is another mod I just thought of for anyone looking for a little "gotway peace of mind". Stencil "Gotway" on your helmut,(if you have one).This is what @Marty Backedid and he has owned 3 ACM's; including my ACM before it became the world famous ACM2040,a Monster and Msuper v3 and has never had any motor connector problems.Obviously @Marty Backehas the blessings of the "Gotway Gods!":)

I didn't want to suggest this myself, but now that you've brought it up, I concur whole heartily :D 

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I found it @meepmeepmayer. I think it was @Hunka Hunka Burning Love that said there might be a hidden screw preventing the inner shell removal.  One little screw prevented the shells for coming apart! This part of the ACM I trust!

Hope this helps if your proceed to tear into your wheel! Good luck!

 

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Another weak point in Gotways is under the motor cover. The other ends of those famous wires. Half of their length is not protected by individual sleeves and being held in place by a tight clamp that would cut the hot isolation as a knife. 

And I suspect there is another trio of connectors under the sleeves?

(The picture belongs to MSuper and was taken from there: http://transporteco.ru/2017/03/20/foto-otchet-po-to-1-dlya-msuper/ )

Wires inside motor.jpg

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3 hours ago, Rehab1 said:

I found it @meepmeepmayer. I think it was @Hunka Hunka Burning Love that said there might be a hidden screw preventing the inner shell removal.  One little screw prevented the shells for coming apart! This part of the ACM I trust!

Hope this helps if your proceed to tear into your wheel! Good luck!

 

You owe me a nickel.  6b567c5d48.jpg  Wadiditellya?  Time to update my signature line me thinks...:whistling:

Edit:  Googling the temperature of cigarette lighter flame, it shows a bit under 2000C.  Maybe another test might be to place the heat sleeve over a soldering iron tip and see how long it lasts under temperatures closer to about 200-300C?  I doubt the wires themselves are getting that hot, but at junctions like connectors or pinched areas they could be putting off some heat making their insulators less effective.  The thermal sleeving could be helping to isolate individual wires and keep the heat from adding to each other.  I'd be curious to see what @esaj thinks of my arcing theory.

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1 hour ago, jrkline said:

When I overheated my ACM,I was climbing fire access roads in the foothills above my house.The ambient temp was 75F and I ascended hills with constant 20 to 30 degree grades for about a mile before it overheated.This was done on My modded ACM 2040 which has 3X the original battery wh capacity of 680wh for a total of 2040 wh.The wheel itself weighs 57lbs. and my weight is 200lbs.A 257lb. load for these conditions is a very well designed wheel in extreme conditions.When the wheel reached 79C it went into tilt mode and beeped just like when I overheated my KS14C except it (the 14C) shuts down at 69C.After my ride I inspected the motor connectors and there was no sign of overcurrent at the connectors due to faulty connectors but obviously many connectors are faulty and seemingly are the weak link(s) in these machines.The next mod for the ACM2040 will be the deletion of the motor connectors altogether.They are used for ease of assembly and really aren't needed by the end user so if anyone has concerns about the weaknesses of a Gotway,that is the mod that would I would recommend for peace of mind.

That is really interesting!

I estimate my ride length to 1400m which is less than a mile. The slopes also certainly weren't up to 30%. Also I think I'm less "donut" than you;) It was colder than your ride.

So the only difference is 67V vs 84V (or just bad luck?). If I had done it with a 67V ACM, or if the cables were stronger on my 84V, would I have just gotten a temperature warning and that's it?

That's really what I'm so unsure about: assuming you can fix the motor wires, could you trust the wheel then?

Return or repair, I'm torn. ???????????????????????????????

1 hour ago, jrkline said:

There is another mod I just thought of for anyone looking for a little "gotway peace of mind". Stencil "Gotway" on your helmut,(if you have one).This is what @Marty Backedid and he has owned 3 ACM's; including my ACM before it became the world famous ACM2040,a Monster and Msuper v3 and has never had any motor connector problems.Obviously @Marty Backehas the blessings of the "Gotway Gods!":)

I always thought the point of the GW sticker was so other people see it, and then they can pre-dial 911, get out their first aid kits, etc in advance:P

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Interesting cable discussion, everyone. @Radislav's picture tells me a lot of work would be required to use stronger cables, if that's even completely possible.

I'm also on @Xima Lhotz's side. Designing a wheel properly can't be that hard, can it? Looks to me they just took off-the-shelf parts they could find, and put them together like lego, without too much second thought.

@Rehab1 Congratulations on your successful treasure hunt, and interesting pictures and videos (fire video, lol). I have no plans for opening the wheel further, unless I'm deciding for a full scale "everything" operation. Maybe I'll try to separate the wires later if it does not "damage" (:rolleyes:) stuff more, and see how the motor behaves (still locked). Right now I'm being as minimally invasive as possible.

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1 minute ago, meepmeepmayer said:

<snip>

Return or repair, I'm torn. ???????????????????????????????

<snip>

Given your relative (compared to me in California) nearness to Speedfeet, I would have him repair it. I suspect the wiring would be better than the factory once Ian is finished with it.

It's rather bad luck that this happens at all (based on the hundreds/thousands which have been sold). It's rare indeed for someone to get struck by lightening twice, so you would be really safe :D

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1 minute ago, Marty Backe said:

Given your relative (compared to me in California) nearness to Speedfeet, I would have him repair it. I suspect the wiring would be better than the factory once Ian is finished with it.

It's rather bad luck that this happens at all (based on the hundreds/thousands which have been sold). It's rare indeed for someone to get struck by lightening twice, so you would be really safe :D

Wouldn't the exact same thing happen again? It's the cables after all, not some bad connectors. What would change after a repair?

You really think bad luck was involved? My impression was the total opposite - I just did something the wheel can't do.

"statistical safety" lol

Maybe I should write Ian just with the problem description, and decide for return or repair later...

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12 minutes ago, meepmeepmayer said:

Wouldn't the exact same thing happen again? It's the cables after all, not some bad connectors. What would change after a repair?

You really think bad luck was involved? My impression was the total opposite - I just did something the wheel can't do.

"statistical safety" lol

Maybe I should write Ian just with the problem description, and decide for return or repair later...

You still haven't talked to Ian???  Well, I have to say at this point you have all the possible information that a person can have regarding this problem and you're just going to have to make a command decision and move forward one way or another. Good luck with your choices and hope you can get back to riding and fun soon :)

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21 minutes ago, meepmeepmayer said:

That's really what I'm so unsure about: assuming you can fix the motor wires, could you trust the wheel then?

Return or repair, I'm torn. ???????????????????????????????

What did Ian say about the wheel?  Did he see the photos?  He'd be the best person to tell you whether he can get your wheel repaired to a level that would last through the type of riding you're expecting of it.  He could tell you if a return is even on the table of options.  Personally I think @EUC Extreme has been way ahead of the game many months ago when he showed us how he replaced his motor wires with heavier gauge wiring and also changed out his connectors.  I believe he also installed extra heat sinks.  He had suggested to Gotway to move to thicker wiring, but they did not do it.  I'd bet if you had something similar done, the wheel might have a better chance to meet your expectations.

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Ok ok I get it, I'l write Ian first and make the decision later. Sorry if I'm stressing everyone out by going so slow:mellow:

I just don't know much about electronics, if it's my fault or the wheel's or just bad luck, all that stuff. The answers her were very helpful in getting a feel for the issue though.

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I don't think it's your fault your wheel shorted out by just riding on it.  We're not stressed.  We're just a group of passionate people who want to see your issue resolved and to help you out.  It's a great community of folks we have here with a wealth of combined knowledge and experience.  But to continue helping you, you need to help yourself to those first steps and talk with Ian to see what options he has for you. 

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2 photos depicting the upper and lower mosfet banks attached to the 'so called' heat shield. In my opinion the heat sink on the ACM 1600 is nothing more than a piece of extruded aluminum. There are no fins to dissipate the heat.

Another upgrade added to my discrepancy list.

 

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@Rehab1 Your... trial and error is very helpful in getting me to decide if that's the stuff I want for myself... sorry if I'm laughing right now, if happened what the deleted posts make one think happened:D

:thumbup: You're doing the good work!

...

..... and now the post is back again? Mysteries...

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15 minutes ago, meepmeepmayer said:

@Rehab1 Your... trial and error is very helpful in getting me to decide if that's the stuff I want for myself... sorry if I'm laughing right now, if happened what the deleted posts make one think happened:D

:thumbup: You're doing the good work!

 

I am actually having fun! This takes me back to my creative days when I had lots of time to invent and fabricate unique things. It sucks your wheel is currently broken:crying: Hopefully something positive will come out of this ordeal. :) Hang in there!

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I found some heat sink FINS!

Interesting piece of engineering. Upon further disassembly I located 12 milled fins on the bottom of the extruded aluminum that is used to support the circuit board and Mosfets. The fins strategically fit into an opening molded into the case allowing the heat to be vented outside the enclosure towards the wheel. The wheel  acts as a fan to further dispense the heat as it spins. 

Feeling a bit better!:)

 

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1 hour ago, Rehab1 said:

2 photos depicting the upper and lower mosfet banks attached to the 'so called' heat shield. In my opinion the heat sink on the ACM 1600 is nothing more than a piece of extruded aluminum. There are no fins to dissipate the heat.

Another upgrade added to my discrepancy list.

 

This is cool, but My God, you are really going at, disassembling your wheel to the extreme. Next you're going to be resoldering the mosfets ;)  And this from someone that hasn't actually had any problems. I got to hand it to you, but my mind is not into doing this kind of stuff (at least right now). I watch with fascination (and distance)  all of you guys :thumbup:

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2 minutes ago, Rehab1 said:

I found some heat sink FINS!

Interesting piece of engineering. Upon further disassembly I located 12 milled fins on the bottom of the extruded aluminum that is used to support the circuit board and Mosfets. The fins strategically fit into an opening molded into the case allowing the heat to be vented outside the enclosure towards the wheel. The wheel  acts as a fan to further dispense the heat as it spins. 

Feeling a bit better!:)

 

That part I did know about from older posts somewhere. Glad you're feeling better.

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How difficult is it to replace wires into the motor?

I think that some wire maybe a little damaged when bending, so it cannot carry the amp it said to be able to carry which is already low even it is not damaged.

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