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Marty Backe

The Gotway Gods Destroyed My ACM

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6 hours ago, Marty Backe said:

BTW, I was somewhat afraid to post my experience for fear of scaring people away from Gotway. Yes, Gotway still has cable harness issues. They are far from perfect. But what happened to me occurred during a long very steep incline. 98% (I'm pulling that figure out of my butt) of EUC riders of Gotway wheels will probably never ride under the conditions that I was riding yesterday.

Don't give up on Gotway folks :)

I would think all wheels would have this issue unless the circuit limits the peak current and proper temperature monitoring to alert. Your wheel did not make any beeps even though the temperature was high enough to melt. The monster did make beeps and survived..

i think good cables can handle 200c or 392f.

silicon cables might handle more. But if the gage is not increase or the current limited, the heat will still build up. 

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3 hours ago, zentype said:

All recorded on video for posterity :D 

While it definitely sucked frying the wheel, I'm glad it didn't result in any serious injuries.

Though for the majority of us fellow enthusiasts, I'm almost positive our first reaction after a crash is "is my wheel OK???"  

Or, "Where is it???"

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6 hours ago, LanghamP said:

I will say that when I was into sportbikes we'd have a couple guys each season have terrible accidents. Hardly a year went by that a riding buddy didn't die, it was uncommon yet regular.

I'm so glad I got into wheels as they have the feel of sportbikes but we can just laugh at Marty's misfortune, he can complain about aches the next day, and there might be the occasional injurious faceplant.

Yet I don't really see the injuries I see from sportbikes and sportbikes.

I hear you... I was hit on my sportbike on the freeway by a drunk driver years ago that I was lucky to survive... Maybe that's why Monocycles appealed to me.. (especially the highspeed models like the msuper) because it helped filled the "gap" left behind from riding sportbikes.

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22 hours ago, KingSong69 said:

But when the machine just cutOut for technical reason, just stops working from one nanosecond to the other, that has Burned into my brain how dangerous it is what we are doing here!

I mean, sure i am still driving, but safety has more and more become one of my main Focus when mounting on a wheel.

Do you have any thoughts about why failures of this type do not seem to be happening with King Song?

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6 hours ago, Marty Backe said:

Don't give up on the ACM. It's still a great wheel (my favorite), and I can't wait to get it back in working order. Learn from my experience and don't stress the wheel on excessive climbs for long durations. I have over 1400 miles on three different ACM's (sold the first two for upgrades). Today was the first failure, and only because of the hill I tackled.

I also have a Monster and MSuper V3, which are great machines too.

Keep an eye on the Local Groups forum. I post group rides there all the time. I just added your name to my distribution list so you should see the next announcement. We've had 7 people in one recent ride. We might break 10 this summer.

Welcome back :thumbup:

Interesting that you own all the models I'm considering but you prefer the ACM the most. That's good to know...  I can understand that since I think 16" wheels seem to be the sweet spot for comfortable ride quality and maneuverability.  After going from my first EU (Ninebot One) to the Kingsong 14, then finally the Msuper2... I found that while I loved the agility of the 14" and the speed and spacious pedals of the Msuper, I preferred the Ninebot for overall ride comfort while still being super agile. Its probably why I am looking at the ACM.. A wheel with the speed of the msuper2 but with maneuverability closer to the Ninebot..

Curious, your first two ACMs.. were they sold for the higher capacity models? I'm looking at the 1300wh but not sure if I'd like the extra weight so I might go for the 850wh... (though it wouldn't be much of a step up from my msuper2 that's also 850wh)

Thanks for the welcome back :D, I'll definitely be keeping an eye on the local groups forum. Looking forward to it!

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34 minutes ago, esaj said:

It can be speculated, but probably no-one knows for sure. For the KS16S, it does have several merits (or limitations, depending how you look at them, like lower speed and max power ;)) in the design:

-NTC-temperature resistor placed right next to mosfets / heatsink, measures temperature much closer to where the hottest parts (mosfets) are
-Lower Rds(on) in a single mosfet than the parallel configuration used in ACMs, also avoids the pitfalls of paralleled mosfets, as low Rds(on) -mosfets do not seem to be available, at least not in TO-220 or TO-247 -packages, for voltages above 75V
-Larger mosfet casing (TO-247), can take much more heat and has more surface-area to dissipate it to heatsink
-Lower power, the components, wiring and motor need not take as much abuse
-Likely more conservative limiting in max currents, probably warns of overtemperature with tilt-back or something (never hit it myself)
-BMSs appear to be communicating with the mainboard directly (third wire coming from each battery pack)
-Active cooling (fan) that turns on at higher temperatures, although how long it lasts with all the vibration and shocks, no-one knows

I haven't opened it up to check the wire gauges, the connectors are MT60's, judging by pictures, the motor cabling coming from the mainboard would appear to be the same as the battery wires (14AWG), but whether there are as thick wires on the actual motor-side, I don't know.. If subjected to a high enough current for high enough time, they will probably also melt at some point, but I'd expect the wheel to warn you far ahead of that, or not even allow as high currents.

 

Also, it appears that KingSong tilt-backs from over heating at a much lower temperature (lower 60's) whereas the Gotway tilt-backs at 79 degrees.

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51 minutes ago, zentype said:

Interesting that you own all the models I'm considering but you prefer the ACM the most. That's good to know...  I can understand that since I think 16" wheels seem to be the sweet spot for comfortable ride quality and maneuverability.  After going from my first EU (Ninebot One) to the Kingsong 14, then finally the Msuper2... I found that while I loved the agility of the 14" and the speed and spacious pedals of the Msuper, I preferred the Ninebot for overall ride comfort while still being super agile. Its probably why I am looking at the ACM.. A wheel with the speed of the msuper2 but with maneuverability closer to the Ninebot..

Curious, your first two ACMs.. were they sold for the higher capacity models? I'm looking at the 1300wh but not sure if I'd like the extra weight so I might go for the 850wh... (though it wouldn't be much of a step up from my msuper2 that's also 850wh)

Thanks for the welcome back :D, I'll definitely be keeping an eye on the local groups forum. Looking forward to it!

I started with the 680wh, then moved to the 820wh, and when the 1300wh was released I bought that. Had a bit over 600 miles on that wheel before this incident.

There is a big jump between the 1300wh and 820wh. Not only the longer range, but because it's a 84v system it has more power and a higher top end speed. And because the wheel is wider between the feet, it feels more agile than the 820wh version. If it's in your budget I would recommend the 1300wh version.

If you're still looking when I get my ACM working again you can try mine.

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3 minutes ago, Marty Backe said:

Also, it appears that KingSong tilt-backs from over heating at a much lower temperature (lower 60's) whereas the Gotway tilt-backs at 79 degrees.

Could be, so far it appears I haven't been able to push it into high enough temperatures for that to happen. The highest I've seen in the app was something like 48 or 49 degrees.

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1 hour ago, esaj said:

-Active cooling (fan) that turns on at higher temperatures, although how long it lasts with all the vibration and shocks, no-one knows

From my  KS Thailand Meeting, where i rented one of the oldest and most "mocked up" KS16, the fan was still working fine. (And in there temperatures it has to workented A LOT :-) )

 

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@HermanTheGerman Really looking forward to your track data. From your description, I suspect the 16B could do it, and the ACM would have melted down. Or maybe not, who knows (we don't, that's the frustrating thing. No way to find out when it would fail except actual failure.)? If you feel like risking your wheel, I can tell you where I melted my ACM and you can try with your 16B;)

Totally agree with you, not everybody lives in flatland, and some people (*cough* me!) want to use their wheels for mountains, at least not too crazy ones. 15% or 20% permanent incline should be doable. But are not (reliably). More %, you can start arguing if that's expecting too much.

Distance should not matter, as long as that distance is at normal currents that produce normal temperatures. The overheating only starts at higher currents when the heat can no longer be conducted away fast enough and accumulates, ultimately melting the cable insulation. Only these parts of the ride are important, no matter what came before. So Marty could have taken a break before that hill, and still most likely the same thing would have happened (or he would have got maybe an extra 10 seconds of riding up before the melt down).

edit: What's your weight? 80kg for Marty (and me). Assuming you're not significantly lighter?

Edited by meepmeepmayer

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7 hours ago, HermanTheGerman said:

I missed that, thanks for pointing it out, I loved it. :lol::lol:

 

Yeah, but I don't think about a Kingsong testramp. 

If one lives in the flatlands that hill may look extreme, but here in Styria a street like that is quite normal, and of course I expect that my wheel survives it. As mentioned a good comparison would be if I go up to Schweizeben with my KS16 (which I already did, but from a nearer distance than Marty rode before his incident), but this time not only from Bruck, but from home, that should result in a comparable distance, and even more hilly terrain for the whole ride.

I'll track the ride with Wheellog and a GPS, maybe I can do a short Video (though I only have a normal digicam) to report how the KS16 behaves.

Not sure if I can do it before the weekend, but I hope.

Pictures would be just as good showing the incline. Posibly a map of the route. Maybe google street view can show the imagery of the street. 

In regards of design. The EUC engineers need to get it together. Over current, BMS shutdown, over speed, overheating with no electronic protections or alerts is not acceptable with today technology.  The amount of PWM duty cycle determines the current on the motor and secondarily allowed to max-or-min based on wheel Rpm. There is an max rpm that the wheel generates voltage equal to v-bat so there will be 0 delta volts and zero current at the max rpm regardless with the MOSFET are commanded by software to do 100% duty cycle. 

At the same time if the wheel is not spinning or spinning very slowly, the software can command 0 to 100% PWM duty cycle based on rider demands. 

So the electronics in the EUC have all the hardware needed to know how much current is flowing because it know rpm and duty cycle with are convertible to current. The temperature sensor location could be changed. The one that needs possibly improve the is Back-BMF overvtage due to overspend. Also fly-back protection might need to improve due to possible overvtage due to incorrect timing of PWM signal. When the PWM is switch off there is potential of a inductive spike coming back from the coils. If another on/cycle occurs at the spike then the MOSFET COULD BE DESTRUYED. 

WARNING:

you indicated that you expect your EUC to be able to do the hills. Please be carefull. EUC design has not taken that level of consideration yet. In my opinion. The current EUC designs are only capable of riding safely on flat city environments with quality road surface.  Don't get me wrong. The machines do work great but they are not trucks or tanks or flying machines. I think they are more like delicate sports cars. You don't ale your Ferrari to a dirt road or off road or jump up and down. My opinion is to treat your EUC like a sports car and don't push the limits. It might not be able to alert you. 

I only have one crash due to ignoring alerts. 

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Do smaller wheels make better climbers on steep hills?

I ask because I feel my KS14C can climb much steeper hills than my MSuper. The MSuper can climb less steep hills much faster but the KS14C seems to easily climb hills I can barely walk up.

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7 minutes ago, LanghamP said:

Do smaller wheels make better climbers on steep hills?

I ask because I feel my KS14C can climb much steeper hills than my MSuper. The MSuper can climb less steep hills much faster but the KS14C seems to easily climb hills I can barely walk up.

Yes, the smaller the wheel the easier it is to climb. My 14C is a great trail wheel. Unfortunately it's not comfortable to ride on a bumpy trail and it overheats too easily.

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Problem is the manufacturers using e-bike parts or derivatives of those, hence the thin axles, hence the thin wires as they have to fit through there. I'd guess they are not that stupid/careless and would not use these thin wires with more space in the axle.

Edited by meepmeepmayer

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22 hours ago, Marty Backe said:

We need a KingKong

If you knew someone with a KS16S, and you got your ACM repaired, and the batteries were the same size, the two of you could try that hill, keeping the same speed, and see which one gets the farthest.  If the rider weights were not the same, adjust with backpack weights to equalize.:popcorn:  Of course, on that hill, they probably both would burn up.:whistling:

I was amazed that the ACM did as well as it did, very impressive!  Great video of the ride, showing different angles from two cameras, you guys must be in the film industry.B)  

Just noticed you said KingKong.:)

Edited by steve454

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Man, that sucks @Marty Backe ... Did Gotway give you an estimate on when they'll send you a new control board? I'm going to do what @jrkline suggested and solder the control wires together without and get rid of the connectors. Also, I'm going to order a couple of wire insulators to go over the existing wires individually, actual heat insulators used on turbo oil lines in cars. There will be better times.

Cheers Man,

sw

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14 hours ago, KingSong69 said:

From my  KS Thailand Meeting, where i rented one of the oldest and most "mocked up" KS16, the fan was still working fine. (And in there temperatures it has to workented A LOT :-) )

That's good to hear. I wondered if the fans would be robust enough!

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27 minutes ago, swvision said:

Man, that sucks @Marty Backe ... Did Gotway give you an estimate on when they'll send you a new control board? I'm going to do what @jrkline suggested and solder the control wires together without and get rid of the connectors. Also, I'm going to order a couple of wire insulators to go over the existing wires individually, actual heat insulators used on turbo oil lines in cars. There will be better times.

Cheers Man,

sw

I know this sound backwards but the issue is heat dissipation. If you add more insulation, the inner insulation will melt sooner because the heat is comming from the cable. 

I don't have an answer other than put some kind of spacer to separate the cables and improve cooling. 

Bit the ultimate solution is

- limit the amount of power with software which we can not have. 

-limit the amount of power by keeping track how hard you ride our add a remote temperature sensor glued to the bullet connectors. 

- thicker wires. 

Edited by Carlos E Rodriguez

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14 minutes ago, Carlos E Rodriguez said:

I know this sound backwards but the issue is heat dissipation. If you add more insulation, the inner insulation will melt sooner because the heat is comming from the cable. 

I don't have an answer other than put some kind of spacer to separate the cables and improve cooling. 

Bit the ultimate solution is

- limit the amount of power with software which we can not have. 

-limit the amount of power by keeping track how hard you ride our add a remote temperature sensor glued to the bullet connectors. 

- thicker wires. 

 

IMG_1413.PNG

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6 minutes ago, Carlos E Rodriguez said:

 

IMG_1413.PNG

Any testing by guys should only be done to record the temperature at critical points inside wheel and stop before failure. Running until it burns is stupid. 

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