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

[US69]

5 minutes ago, Marty Backe said:

There's nothing preventing (is there?) Gotway from feeding cables thru both sides of the wheel.

or even better: making the diameter of the center axis bigger:-)

[Marty Backe]

48 minutes ago, meepmeepmayer said:

If I keep it, I want to be sure that won't happen again. So a repair would have to ensure that. Is that even possible? No crashes without warning, that's what I want.

Whether I wait (for a loooong time probably) or go for a KS16S (or I don't know what, maybe the coming KS18 if it's good)... I don't know. And yes, I like EUCing, but riding while never knowing how close to a crash you are is not fun! For flat land "safe" rides it's just too expensive (and are they even safe?). I have no idea if my 1.5h mountain ride immediately before that was dangerous or not, that's what pisses me off the most. Did I enjoy it while 1% from disaster?

It gives me no pleasure in saying this @meepmeepmayer, but there is inherent risk in riding high performance wheels like the ACM. If you can't truly enjoy your rides because of constant questions in the back of your mind, maybe a slower and less powerful wheel would be better for you. That's not a bad thing - everyone has their own comfort level.

But any self balancing single wheel device that goes faster than walk-off speed is going to have some inherent risk - no way around it.

[US69]

1:00 p.m.  here...

goood night!

@meepmeepmayer keep us informed of Ians answer please...

And you know what: Most important is....that nothing happens to you on your accident!!!

with that said....All sleep well!

[meepmeepmayer]

11 minutes ago, KingSong69 said:

Nope, not really, but:

GW lets all responsibility in the hand of their customers...KS for example goes a safety first way...with the result, that nobody buys them because of their "bad performance "...

I guess the true answer- no offense meant- is that pushing a 120cell euc up a fat hill for longer than lets say a minute...is not possible in the moment...

As here was no overcurrent...just a to long used high current...

That's what I'm going for, with a KS it would probably just have beeped at me to stop, and everything's good (my current rose colored KS glasses say that). That's my impression of the KS at least. Main reason for ACM was the big battery, otherwise I might have gotten a KS (well I also really like the sturdy ACM design, but the KS handle might have beaten that alone).

@Marty Backe Why would any high performance wheel be more dangerous (except going faster, which isn't my thing)? Higher safety margin while doing the same things like with a weaker wheel. I really just want wheel designed to warn you before anything predictably breaks (high current/temperature or whatever aren't random events) If I had too much money, I'd start a EUC manufacturer right now... (dreaming of nicely feathered pedals)

@KingSong69 Good night and thanks a lot (to everyone as well). I will write Ian tomorrow evening (other stuff comes first unfortunately) with the pictures etc. Still not sure if repair or return (if he accepts a return) is the better idea.

[steve454]

41 minutes ago, meepmeepmayer said:

So how much "mountain" exactly is allowed?

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.

[Marty Backe]

6 minutes 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.

Gotway's do power down when they overheat. At 79c tilt-back starts kicking it to force you off the wheel. But that's probably to protect the mosfets. The cabling heat is a totally different matter.

[steve454]

25 minutes ago, meepmeepmayer said:

I went down the hill with the wheel on my back, and it took 20 min (I checked the time).

What?  You carried the wheel on your back as you walked?  That's a good workout.

[steve454]

10 minutes ago, Marty Backe said:

Gotway's do power down when they overheat. At 79c tilt-back starts kicking it to force you off the wheel. But that's probably to protect the mosfets. The cabling heat is a totally different matter.

That appears to be a misbuilt vehicle warranty issue.

[Rehab1]

On 3/17/2017 at 9:42 PM, Linnea Lin Gotway said:

Hi @meepmeepmayer,  your wheel should burnt the mosfets, not the problem of cables. Since the end of November, 2016, we changed the cable connectors. There are only some Msuper V3 1600wh models has such problems. ACM 1300wh/1600wh and Monster were began to make after we changed the new connectors. I enclosed the pictures of both connectors. We use cold pressing technology to avoid the cables slip off again when the high tempreture melted the tin solders. Your wheel should be burn the mosfets as you keep climbing the moutains, the high temperature make the mosfets burn. Please check it with your seller to change the mainboard. 

Just a refresher course from @Linnea Lin Gotway comments above:

1)"Hi @meepmeepmayer,  your wheel should burnt the mosfets, not the problem of cables."

2) "Your wheel should be burn the mosfets as you keep climbing the moutains, the high temperature make the mosfets burn."

3)" Please check it with your seller to change the mainboard."

Not to sound disrespectful but this is BS at it's finest!

[steve454]

17 minutes ago, Rehab1 said:

"Your wheel should be burn the mosfets as you keep climbing the moutains, the high temperature make the mosfets burn."

That is good info, thanks.  (Actually @Linnea Lin Gotway said that but thanks to @Rehab1 for pointing that out).

[Marty Backe]

8 minutes ago, Rehab1 said:

Just a refresher!

1)"Hi @meepmeepmayer,  your wheel should burnt the mosfets, not the problem of cables."

2) "Your wheel should be burn the mosfets as you keep climbing the moutains, the high temperature make the mosfets burn."

3)" Please check it with your seller to change the mainboard."

Not to sound disrespectful but this is BS at it's finest!

I wish that I could give you a reputation, but apparently I can only give 40 a day - what the hell???

[Hunka Hunka Burning Love]

  Ah remember that some of you might need future warranty help from Gotway reps.  Might not be wise to burn those bridges yet.    Linnea has always tried to be helpful as far as I have seen.  I don't think she has a personal say in how these wheels are spec'd out and put together.

Besides, don't blame the rep, blame the chief design engineer that green lights these projects.  Sometimes though it's just a case of not realizing that certain wires might heat up softening and weakening their insulation properties allowing things to arc and burnt up.    I think Gotway needs to test their wheels wih riders wearing sandbag vests on that steep climb that KingSong uses where @jrkline tested one of their wheels out on.

It also appears that current generation wheels have that extra protective heat shielding,  but it might be wise to have individual sleeves for each wire coming from the motor which is a simple mod to do most likely.

At least they have reps that sometimes visit the forums to help field and pass on concerns.  Um Ninebot rep?  Hello?  Anyone out there?

[Goodman]

I just bought a Msuper V3S+ 1300 last week waiting for it to arrive, should I be trembling in fear? Maybe I'll be fine no major hills where I live, Australia is almost a flat piece of land, but I am really sorry to hear this has happened.

A random guy sent me a text last week telling me I made a error on a local post I was using to sell my ninebot one e+, he was going to copy and paste my add. I asked him why he was selling, and his reply was he was going up a hill full speed and the wheel cut off. He had his hands in his pockets and face planted onto the foot path at around full speed no beeps or tilt back. Poor guy had some serious injuries so can't really blame him for waiting to sell.

EUC are extremely fun, but buying one currently has it's risks , there is not millions spent on development and testing as the industry is fairly small. So I'm guessing we are all sort of guinea pigs and in some ways part of the solution, kind of bad for us but hopefully better EUC's will be built in the near future. I am sure all the current EUC makers will be looking at these posts and working out solutions well at least those that do and try will be the ones that survive.

I myself will have learnt a lot from all the input and will now take steps to hopefully give me a safer way to ride, nothing is ever going to be close to 100% safe but thanks to you guys I won't be doing anything too stupid.

[Rehab1]

1 hour ago, Hunka Hunka Burning Love said:

Linnea has always tried to be helpful as far as I have seen.  I don't think she has a personal say in how these wheels are spec'd out and put together.

I have always agreed with you so please don't take this personally. Linnea appeared to speaking from authority, someone that had specs and photos to back up her statements! Possibly someone of authority within the Gotway corporation is feeding her false information in an attempt to pacify us!

On another note the excessive temperatures being generated within the confines of the ACM housing has me so concerned that I just purchased a Bluetooth temperature data logger ( different than my current logger) where I can access the data through my iOS phone. It also allows me to set alarms to alert me if the temperature goes above my preprogrammed temp threshold. 

I am not sure what the high temperature threshold will be set at but I can guarantee it will be set low enough to prevent my wires from melting!

 

[Marty Backe]

25 minutes ago, Goodman said:

<snip>
He had his hands in his pockets and face planted onto the foot path at around full speed no beeps or tilt back. Poor guy had some serious injuries so can't really blame him for waiting to sell.
<snip>

One big take-away from random guy - please don't ride fast with your hands in your pockets 

[Marty Backe]

16 minutes ago, Rehab1 said:

I have always agreed with you so please don't take this personally. Linnea appeared to speaking from authority, someone that had specs and photos to back up her statements! Possibly someone of authority within the Gotway corporation is feeding her false information in an attempt to pacify us!

On another note the excessive temperatures being generated within the confines of the ACM housing has me so concerned that I just purchased a Bluetooth temperature data logger ( different than my current logger) where I can access the data through my iOS phone. It also allows me to set alarms to alert me if the temperature goes above my preprogrammed temp threshold. 

I am not sure what the high temperature threshold will be set at but I can guarantee it will be set low enough to prevent my wires from melting!

 

Very cool. I can't wait for you to re-assemble your ACM and report back with your new instrumentation. But I'm wondering if you will even push the wheel enough to generate heat, now that the Fear of God is in you with regards to Gotway 

[Hunka Hunka Burning Love]

29 minutes ago, Rehab1 said:

I have always agreed with you so please don't take this personally. Linnea appeared to speaking from authority, someone that had specs and photos to back up her statements! Possibly someone of authority within the Gotway corporation is feeding her false information in an attempt to pacify us!

  Agree with me or disagree - I respect everyone's opinions.  Friends don't hold grudges just because we might not see exactly eye to eye on every subject.  It would be boring if we all had the same opinions on subjects.  It would be like yup yup yup I agree yup yup yup yawn 

I think Linnea came to the same quick conclusion as I did when she heard the motor was locking up thinking that the MOSFETs could be the culprit.  Wires arcing and shorting together is pretty rare so it wasn't high up on the list of possibilities although @zlymex previously posted some shocking photos of melted connectors.  She probably thought meep's wheel had the heat sleeve protectors on so a wire issue was not likely.

In any case I can understand the fear, anger and worries a failure like this can plant in the back of one's mind, and after paying the big bucks this shouldn't be something that anyone should have to worry about.  That BT thermal monitor is quite a smart idea to keep an eye on things.

[Rehab1]

13 minutes ago, Marty Backe said:

 But I'm wondering if you will even push the wheel enough to generate heat, now that the Fear of God is in you with regards to Gotway 

Did I mention that @EUC Extremewill be riding my modified wheel up the highest mountains and down the roughest canyons to test it out 

[Marty Backe]

Just now, Rehab1 said:

Did I mention that @EUC Extremewill be riding my modified wheel up the highest mountains and down the roughest canyons to test it out 

[Michael Vu]

So, is this issue really happening to ALL gotway models? Or just the 84V versions? I push my 67V ACM and Msuper V3 (1000+ miles) all the time and haven't had any issues so far.

[Xima Lhotz]

On 3/18/2017 at 1:02 PM, esaj said:

A separate sensor in direct contact with the heatsink would probably work better.

Yes i agree, i think both sensors are needed. (we now know it was the cables but thats completely different and also an super easy fix)

And while an extra sensor adds protection there is also more that can be done code wise to predict heat generation.

What I'm saying is: if current temp = X degrees, and Y amount of current goes through the bord within Z amount of time, then the temp will be Q.

This is totally predictable within some limits (those limits would then have to be accounted for). 

I think there is a "simple" algorithm to predict heat in combination with temp, current, speed to protect the board from every failing (due to known forces).

(If nothing that cant be predicted fails like battery or discrete components)

 

[OliverH]

29 minutes ago, Xima Lhotz said:

Yes i agree, i think both sensors are needed. (we now know it was the cables but thats completely different and also an super easy fix)

And while an extra sensor adds protection there is also more that can be done code wise to predict heat generation.

What I'm saying is: if current temp = X degrees, and Y amount of current goes through the bord within Z amount of time, then the temp will be Q.

This is totally predictable within some limits (those limits would then have to be accounted for). 

I think there is a "simple" algorithm to predict heat in combination with temp, current, speed to protect the board from every failing (due to known forces).

(If nothing that cant be predicted fails like battery or discrete components)

 

But then you need to go on the bench and do test runs, note down the numbers. Than doing setup modifications and test again. After founding the correct values a release is ready. That's basic servicemanagement. I never had the impression this happen today in the so called development step.

[Xima Lhotz]

6 hours ago, Michael Vu said:

So, is this issue really happening to ALL gotway models? Or just the 84V versions? I push my 67V ACM and Msuper V3 (1000+ miles) all the time and haven't had any issues so far.

This affects any wheel that have the wrong dimension of cables for the current thats allowed goes through them.

 

Other thoughts around the general design of wheels.

Adding heat "protection" sleeves is just mad, thats like: "my hands are so warm, where are my heavy duty gloves to cool down"

Those protection sleeves are for protecting cables that are surrounded by heat, not to increase the protection of heat produced by the cable. Like in a sauna light fixture for example (you put those sleeves on the ends of the cable to protect them from the surrounding heat of the sauna).

The worst part here is inside of the engine cable (or where the cables touch).

There is no surrounding air and all three cables are pressed against each other. The reason it failed in the beginning where all the cables come together is that the plastic of the cables (where the cables are closer to each other) gets so hot it melts, shaking while driving the wheel "moves" the plastic creating the short. This might not happen inside the cable as easy as the plastic even when melted "holds" the copper wires more in place.

Even if there wasn't a short, imagen the cables (with all cables) (and inside the sleeves) with that heat after a year of riding, it will fall to dust.

To me this is super simple and totally predictable, Demand = X amps reqires Y mm2 cable = done!

This is how all installations of electricity is done in every house since the dawn of electricity. (after all the initial learning curve and some fires) but thats all past now. 

But after this, there is the next step in the chain, if the cables now melt and we increase to X mm2 to the correct one for the current, how much can the coils in the motor take before they break / melt?

Same thing with tuning your car, fix more power from engine, clutch breaks, fix clutch, gearbox break, fix gearbox, axles break, fix axles, new sticky tires, engine needs reinforcing due to heavier load and on it goes...

Unless you decide from the beginning in the design that power of the "engine" is X and then design around that, its always "patchwork".

[Xima Lhotz]

2 minutes ago, OliverH said:

But then you need to go on the bench and do test runs, note down the numbers. Than doing setup modifications and test again. After founding the correct values a release is ready. That's basic servicemanagement. I never had the impression this happen today in the so called development step.

 Yes, this it true, there might be some steps missing in testing.. 

But even so, not doing the actual maximum heavy duty testing in real life i think its calculable within the required % for being (almost) failsafe. (Depending on the failsafe % margin you use)

Correct cables for the required current, connections being able to handle the current, correct mosfet for the power delivery, maximum temperature,  for example.

But i also completely agree, real world maximum testing until it breaks (this should never happen in the finished design) is always needed to understad the true nature of a design to find the problems that cant be calculated or predicted properly when its a finished product. Its not that difficult (to me)

[Rehab1]

Returning to work this morning I immediately began pealing back the insulation of the green, blue and yellow 14 gage wires originating from the PCB that are then connected to the 3 motor wires. Interesting the motor wires are 16 gage. Not a sound policy to transfer current from a larger gage wire to a smaller gage. Imagine if your house were wired that way! It would never pass inspection!

The chart below is a refresher of the risk of having solder wick past the crimped connector which can lead to mechanical failure of the wire. All three of my wires were affected!

 

A view of my wires clearly shows the wicking of the solder past the crimped terminal.

These are clearly meant to be obsevations as I slowly work my way through the ACM 1600 to hopefully shed some light on @meepmeepmayer wiring problem. 

Below is a photo of my ACM depicting a possible scenario of @meepmeepmayerwires short circuiting. Until he is able to separate all of the wires this is purely speculation.