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Killed my Ninebot P in 25 miles.


Douglas Ingram

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Hello all,

 

Well I managed to kill my Ninebot P  in 3 weeks from new and with 25 miles on it. 

 

Hiw did did this happen I hear you all asking.  

Well, showing off ultimately.

i was riding along my normal riding area when in the distance I see my friend sitting at the park bench. So taking the P upto full speed for about 400m I raced happily towards them. While on the way I decided to do a real fast stop, leaning back hard to bring my Ninebot P bring it to a halt in the shortest possible distance, well the P did a great job slowing me down to around 4 Mph, before shutting off, no sound, no warning. Never to switch back on again. 

In stopping in this way I killed the board. I'm very surprised you can be able to do this to be honest. 

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12 minutes ago, Douglas Ingram said:

Hello all,

 

Well I managed to kill my Ninebot P  in 3 weeks from new and with 25 miles on it. 

 

Hiw did did this happen I hear you all asking.  

Well, showing off ultimately.

i was riding along my normal riding area when in the distance I see my friend sitting at the park bench. So taking the P upto full speed for about 400m I raced happily towards them. While on the way I decided to do a real fast stop, leaning back hard to bring my Ninebot P bring it to a halt in the shortest possible distance, well the P did a great job slowing me down to around 4 Mph, before shutting off, no sound, no warning. Never to switch back on again. 

In stopping in this way I killed the board. I'm very surprised you can be able to do this to be honest. 

Proper designed by Ninebot ;) They had their good times. 

But you had reset the mainboard? Unplug battery und plug it together after a while? Or is the MOSFET really blown? What Firmware?

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Its looks the same as idling or it might be a BMS shutdown. As @OliverH says, it could be reset by recharging the battery if is due to the BMS shutting down. But Ninebot One should be very durable and should handle that instance for it costs a lot more than other branded EUC's with equivalent motor and battery size. Oh how I miss my Ninebot One. 

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21 minutes ago, SlowMo said:

Bigger motor, bigger current demand and a small battery pack of 320wh could be drained easilly so the BMS might cut in quick or all will burn. Lets just hope it's just the BMS and nothing else.

That's why I wonder IPS and Ninebot followed this route. 

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1 hour ago, OliverH said:

Proper designed by Ninebot ;) They had their good times. 

But you had reset the mainboard? Unplug battery und plug it together after a while? Or is the MOSFET really blown? What Firmware?

New board, was running the old Firmware before this resent one. 

 

Now new board, new Firmware. 

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Just to confirm, I attempted a rapid stop of minimum distance. My friends said I was really tilted backwards at the point of breaking. 

The Ninebot didn't completely stop me before it blew up the board. About 4 mph when I stepped off. 

 

Anyway, new board now fitted. And happy P owner once more, but does concern me that I never managed to do this on my E and I put that through loads. 

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Hi Doug,

Mate, I would be absolutely fuming if that happened to my bot!

For a grand, I'd expect the bot to be able to take that kind of manoeuvre....did you have to pay for a new board or did they send you a new one free of charge?

47 minutes ago, Douglas Ingram said:

Just to confirm, I attempted a rapid stop of minimum distance. My friends said I was really tilted backwards at the point of breaking. 

The Ninebot didn't completely stop me before it blew up the board. About 4 mph when I stepped off. 

 

Anyway, new board now fitted. And happy P owner once more, but does concern me that I never managed to do this on my E and I put that through loads. 

 

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Plain guessing, but a strong braking causes lots of power to pass through the bridges to the batteries... I've seen values momentarily in the 2-2.5kW -range during strong braking with Vee's MCM2s, although it's said that the Gotway board exaggerates the current by about a factor of 2, so it could have been "only" above slightly 1kW. Still, that's a lot of power to dissipate, as some of it is bound to get burned off as heat along the way in the components, and since it wasn't my wheel, I didn't really push it to max speed and do as fast stop as possible (likely to go into still higher values). So it could be that the strong braking from full speed caused large enough power to pass through the components long enough for something to get burned.

Not to say that it's ok for the mainboard to break in such situation, but it does sound pretty extreme case.

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4 hours ago, esaj said:

So it could be that the strong braking from full speed caused large enough power to pass through the components long enough for something to get burned.

I noticed on the Firewheel that the control board had a heat sink that was screwed to the aluminum plate, but there was no thermal paste. It did have some sort of soft tape between the heat sink and the board but it didn't seem to be that good a connection. So if the board does start cranking out a lot of heat for a long period of time it probably isn't going to dissipate very well. The Ninebot seems even worse, there's a heat sink but it's in a closed space so there is no air flow like there would be in the Firewheel. 

Capture.PNG

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26 minutes ago, dmethvin said:

I noticed on the Firewheel that the control board had a heat sink that was screwed to the aluminum plate, but there was no thermal paste. It did have some sort of soft tape between the heat sink and the board but it didn't seem to be that good a connection and there was no paste between the heat sink and the plate. So if the board does start cranking out a lot of heat for a long period of time it probably isn't going to dissipate very well. The Ninebot seems even worse, there's a heat sink but it's in a closed space so there is no air flow like there would be in the Firewheel. 

Capture.PNG

Firewheel uses SMD-mosfets, IRF 7759:  http://cdn-reichelt.de/documents/datenblatt/A100/DS_IRF7759.pdf

As for the "missing" heatpaste between the mosfets and the aluminum-sink, I think the problem is the same as with most mosfets, the outer shell acts as one of the pins (drain?), so you can't have direct metal-to-metal -connection there, as it would short the pins of the different mosfets together through the heatsink, so thermal paste won't work. It's some sort of thermal tape/pad that they use there, don't know how good or bad it is at conducting. But paste could be used between the heatsink and the metal-plate.

EDIT: To stay a bit on the topic, I've done some pretty extreme brakings with the Firewheel (from speeds up to 30km/h), and never had problems with the heat, although, I don't know if there is heat sensor anywhere in the mainboard, so I cannot tell how close to frying the board I've come, and we did have pretty cold summer... Probably occurs easier in hot weather.

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Everyone lets time stop posting other threads until this topic has been followed up throughly. Lets stick to this critical thread$$$$.$$ Has anyone else been able to verify this motherboard burning problem when braking very hard at very fast speed?

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8 hours ago, SuperSport said:

How did you get a new board in a matter of hours?

Lucky I bought through a supplier rather than grey importing. Drove my Ninebot 300 mile round trip to have a new board installed under warranty 

bought through www.speedyfeet.uk

 

great service. 

 

Agree though we we need to keep to the subject. 

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I'm now using the latest firmware update and my P now feeling a little sluggish and a little less responsive. 

Ive notice on ride setting zero, that if you stop quite quickly next to a rail the grab to hold you balance, the Ninebot levels the ride plates about 2 seconds later. It's not as solid on this setting as it was last week.  Please try this for yourself.

 

My thoughts are that Ninebot now know about the boards being damaged by rapid  acceleration and  de-acceleration on the P so released this update to slow it a little. 

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Going down the hill and breaking hard ... wondering if this could possibly burn the motherboard also!!

Face Planting downhill is much more serious compare to level ground.  Battery (340wh or is it 360wh switch?) or software upgrade mistake. Last thing on my mind going defect would be the motherboard, crazy. Reminds me of http://www.macworld.com/article/1140545/nvidiasuit.html

P owners should test their unit before warranty expires. Safety is a concern during test...

 

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4 minutes ago, NinebotOneUser said:

Going down the hill and breaking hard ... wondering if this could possibly burn the motherboard also!!

Face Planting downhill is much more serious compare to level ground.  Battery (340wh or is it 360wh switch?) or software upgrade mistake. Last thing on my mind going defect would be the motherboard, crazy. Reminds me of http://www.macworld.com/article/1140545/nvidiasuit.html

P owners should test their unit before warranty expires. Safety is a concern during test...

 

I believe this is what happened to me when my kingsing broke. I braked hard but i wasnt even going fast, i was going very slow but braked hard with the intention of going backwards. Not only did the motherboard seems to have burned but also the BMS in both batteries from supposedly drawing too high of a current from batteries? Not sure this is what happened exactly but this is my theory. Even though in the past when i braked hard nothing happened, so go figure...

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