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Geowurm

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4 hours ago, lizardmech said:

There's only one kingsong company. My theory is that many of the shutdowns on higher powered models with large batteries are temperature related. They generally have no more cooling than a cheap 350w 130wh model. I saw your youtube video, it was being ridden along a dirt road when it cut out? As off road means a lot more friction the control board would be exposed to more continuous current than on pavement. Do you know roughly how long you had been riding when it cut out and roughly what temperature the weather was? 

We stop halfway for tea after that ride about half an hour the it just happen.the battery still have 4 led.it was night time about 11pm.its not the skill problem it is the motor just suddenly stopped n I lost balance n fell.image.thumb.jpg.abaa15eab9dcd89ea11b520cimage.thumb.jpg.abaa15eab9dcd89ea11b520c

Edited by Jed
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3 hours ago, lizardmech said:

There's only one kingsong company. My theory is that many of the shutdowns on higher powered models with large batteries are temperature related. They generally have no more cooling than a cheap 350w 130wh model. I saw your youtube video, it was being ridden along a dirt road when it cut out? As off road means a lot more friction the control board would be exposed to more continuous current than on pavement. Do you know roughly how long you had been riding when it cut out and roughly what temperature the weather was? 

Probably there are some Kingsong clones or rebranded EUC:  http://monolek.com/index.php?

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1 hour ago, Frankman said:

Probably there are some Kingsong clones or rebranded EUC:  http://monolek.com/index.php?

Hi @Frankmanif you want to purchase a Ks18A,just ask them first whether can do the setting or not!today l ask one more reseller about the setting but they never answer me.they just said can sent,which one,what color that's all.

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Hi Jed why don't you ask   ngray@milbay.com.au   or  info@hightems.eu   they are official Kingsong reseller, and probably  give you some useful answer.

Please, can anybody tell me how to insert at the beginning of my posts the member's name to which I'm going to reply. Means something like this:  @Jed  @SlowMo or others.  Thanks.

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46 minutes ago, Frankman said:

Hi Jed why don't you ask   ngray@milbay.com.au   or  info@hightems.eu   they are official Kingsong reseller, and probably  give you some useful answer.

Please, can anybody tell me how to insert at the beginning of my posts the member's name to which I'm going to reply. Means something like this:  @Jed  @SlowMo or others.  Thanks.

Type @ first and wait for a list to appear then type the first and succeeding letters.

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4 hours ago, Jed said:

We stop halfway for tea after that ride about half an hour the it just happen.the battery still have 4 led.it was night time about 11pm.its not the skill problem it is the motor just suddenly stopped n I lost balance n fell.

Sound's consistent with my theory, EUCs don't really have any cooling for the control board, they just stick a chunk of metal on it. It's like fixing a leaking roof with a bucket. It's not a completely bad solution the first generation EUCs had small batteries they likely calculated it would run out of power well before overheating which would mean it would rest for a minimum of an hour or two to recharge and cool down. Now as motor power and battery sizes have increased stronger or more mosfets have been used, while this helps in short bursts it has no effect on longer trips. Only power, mosfet resistance and cooling have an impact for longer trips, in some cases higher power mosfets even have higher resistance meaning even more heat. While I think kingsong have temperature warnings depending on the location of the sensor there's always a chance another IC is closer to the heat source and has it's own thermal shutdown feature.      

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4 minutes ago, lizardmech said:

Sound's consistent with my theory, EUCs don't really have any cooling for the control board, they just stick a chunk of metal on it. It's like fixing a leaking roof with a bucket. It's not a completely bad solution the first generation EUCs had small batteries they likely calculated it would run out of power well before overheating which would mean it would rest for a minimum of an hour or two to recharge and cool down. Now as motor power and battery sizes have increased stronger or more mosfets have been used, while this helps in short bursts it has no effect on longer trips. Only power, mosfet resistance and cooling have an impact for longer trips, in some cases higher power mosfets even have higher resistance meaning even more heat. While I think kingsong have temperature warnings depending on the location of the sensor there's always a chance another IC is closer to the heat source and has it's own thermal shutdown feature.      

Do you mean the design of the KS-18 is not safe for long trips?

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29 minutes ago, SlowMo said:

Do you mean the design of the KS-18 is not safe for long trips?

It's difficult to say, I think any of them with a large battery could run into this issue. It would probably come down to watts consumed per hour and ambient temperature. A person riding around at high speed for fun is likely to stop and start, while someone commuting on a smooth paved surface won't use much power. But if you have someone commuting across a rough dirt road or up a slight gradient they will produce the most heat as they will be using 200w-400w non stop for a long period of time. In my experience with mosfets in computer parts, mosfets dealing with 300W+ are not easy to cool, have a look at the cooling on expensive PC graphics cards, it's very different to what you see on EUC boards.

Every couple of years some graphics card manufacturer comes up with the idea "those mosfets are rated for 175C, why are we spending money cooling them?" Usually the product is then plagued by reliability problems even though neither the mosfet or GPU are technically run out of spec and is promptly discontinued.  

The easiest way to test this would be to take some of the more powerful models, connect them to a power supply and run them with a moderate load for a few hours and see if they can disperse enough heat or shutdown.

Edited by lizardmech
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1 hour ago, SlowMo said:

Maybe @Jed need to install a custom ventilation shaft opening in the front side and running through the mainboard area and with an exhaust vent on the rear just like what we do for cooling the ESC's of RC Jets.

Hi @SlowMoI guess that my ks18A is not 1200w,it is 800w because l fell that night my speed is 31km/h that read on my iPhone 

because 1200w can run 40km/h,800w can run 30km/h.l think l'll been con!

image.jpeg

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I haven't done any power data capture analysis on the KS18A, but these massive 18" Wheels needs to be packaged with the right type of battery cells. As you can see in the other thread, under even moderate 4.5A loads, these MG1 cells don't hold up well at all. I've pleaded, begged, & tried to convince KS supported by abundant evidence on many occasions that they need to adopt a newer generation battery with a lower Internal Resistance; there are over a dozen choices with better performance characteristics, while I've had some success in getting them used for my recent orders, I still think it's important to protect the brand, & that they make better intelligent choices about these matters.

For the control-board overheating theory, I don't think this is relevant, because (at least on the 14C series) it is programmed very conservatively to go into limp-home-mode when the heatsink reaches just 70°c

 

This is the output of a Ninebot One E, look at how the battery's voltage plummets when the power momentarily spikes to 1500W. 

Regen_on_9B1.thumb.png.09611d75ac30249fa

 

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16 minutes ago, Jason McNeil said:

For the control-board overheating theory, I don't think this is relevant, because (at least on the 14C series) it is programmed very conservatively to go into limp-home-mode when the heatsink reaches just 70°c

It's hard to know, you could easily get hot spots in places, you can have issues where one component only produces 0.5 watts of heat and would normally cool itself, but lock it in a small compartment and heat it to 50 or 60c and it may not. Also although the EUC heatsinks often cover the entire PCB that is counter productive as it transports mosfet heat to other components rather than sending it outside.

Unrelated, but have you ever measured how many amps braking regen is sending into the battery packs? 

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50 minutes ago, lizardmech said:

Unrelated, but have you ever measured how many amps braking regen is sending into the battery packs? 

Limited yes, but @esaj with his custom App has found 2KW in reverse power mode on a MCM2. The App polls the CB, & for some reason, GW have over inflated these figures. Quite how much, no one has ascertained precisely. 

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On December 5, 2015 at 5:56 AM, Geowurm said:

Hi I am using a Gotway Msuper and Osdrich T1 since 3 months now. Never had any problems with these 2 and felt really safe on them.

Decided to get another cheap EU that is lighter. Found one (VEVOR) on eBay stating a weight lighter than the ones I already had.

Last week on a trip to work at about 8 km/h all in a sudden the unit switched off without any warning. This shut down without warning resulted in an accident that caused severe body damages. My right lower leg broke so bad that I needed all my luck to keep my leg! Right now I am still in the hospital recovering from the accident. It will take at least 6 months to recover and I need luck to be able to walk again.

I had never thought that this is possible, and that riding a unicycle is considered as extreme sports. 

WARNING to all EU users. Don’t rely on cheap Chinese imports. They might stall on you causing severe accidents.

Color: Black MPN: X3
Brand: VEVOR Country/Region of Manufacture: China
Model: X3 Wattage:

132WH Lithiu mBattery

s-l1600.jpg

Hi @Geowurmvery sorry about that.lm also suffer this kind of incident.but l'm really upset because my one is kingsong 18A.l thought this brand is good but opposite.l would like to try Gotway msuper.so you got 3 months experience.so 1 thing l want to ask you is that did your msuper ever suddenly motor stopped.eventhough exit the speed limits.

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13 hours ago, Jason McNeil said:

Limited yes, but @esaj with his custom App has found 2KW in reverse power mode on a MCM2. The App polls the CB, & for some reason, GW have over inflated these figures. Quite how much, no one has ascertained precisely. 

Zlymex mentioned once that the current -figure is about twice the reality, so assuming the voltage is correct, the calculated power shown by the app is twice higher than reality. Even then, a fairly strong braking with my quite low weight (~60kg) could cause spikes above 1kW.

Edited by esaj
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14 hours ago, Jed said:

Hi @Geowurmvery sorry about that.lm also suffer this kind of incident.but l'm really upset because my one is kingsong 18A.l thought this brand is good but opposite.l would like to try Gotway msuper.so you got 3 months experience.so 1 thing l want to ask you is that did your msuper ever suddenly motor stopped.eventhough exit the speed limits.

@Jed I was riding my 18 MSuper on a commute basis and never ever had a shutdown. This is why I was so unaware that the generic X3 had all of a sudden a shut down without any warning.

The result is shown below. I am still recovering, 8 weeks after the accident and I will be on crutches for another 2 - 3 months!

Drive careful, and always wear proper protection. Never ever trust your EU if it comes to sudden shut downs.

 

Copy of 2015_12_02-02.jpg

Edited by Geowurm
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