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Accident Report 9b1 e+


fluidfred

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5 minutes ago, Hunka Hunka Burning Love said:

@SuperSport, my reply was actually in response to LanghamP's statement.  I should have quoted it earlier.  When I said "you might not realize from the graph" I was referring to LP, not you.  :innocent1:

Uses most energy from the motor! The 800 watt nominal 2000 watt peak thingy.

Running a wheel has got to be the cheapest form of motorized transportation ever.

 

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This has been very informative. I'm sorry that i came at a cost to the health of @fluidfred.

Thanks for the great reply @esaj and the graphs etc @LanghamP, @Hunka Hunka Burning Love & @SuperSport.

I think there should be a crash course (bad wording I know) that covers all of this for the interested rider. Knowledge is power and this stuff is golden for helping avoid sticky situations down the road.

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@fluidfred- hope you recover well from this accident!

15 hours ago, MaxLinux said:

I am surprised by this recent purchase date because I thought Ninebot stopped making the One E+.

 

13 hours ago, steve454 said:

 

According to electricunicycleonline's website, they stopped production and are out of stock, they recommend IPS.  There must still be some available on Ebay and other places.  Speedyfeet still shows them in stock.  

Ninebot ONE E+ (Gen2) Electric Unicycle

Regular price£579.17 | £695.00 including VAT

 

Want it Tuesday, 4th July?
Order within
1Day16Hrs29Mins
Select Fedex 24 (UK Mainland)

Could be that the 9b1 e+ were quite some time with full batteries in some warehouses? With maybe high temperatures over summertime - so not really optimal for the batteries?!

10 hours ago, WARPed1701D said:

 

  This confuses me. I've seen multiple posts where riders have used WheelLog and seen huge power consumption on downhill braking and then other posts where regerative braking on downhill is discussed. Which is it... Or is it both?

For my KS16C it's both, but a bit hard to differentiate since it does not transmit the current direction. So one has to look at the logs for the "braking points"  and once a high current is flowing search for the corresponding voltage trend - if voltage goes up it's regenerative braking, if the voltage goes down (voltage sag) its non-regenerative braking. It's not really to be distinguished exactly for every case since the sampling rates are a bit too low...  From what i've seen till now regenerative braking happens mostly with about 10-15A charging current. Non regenerative braking happens also with much higher currents...

But that's just from some log examples - far away from a statisticly relevant sample... ;(

10 hours ago, WARPed1701D said:

 So Wheellog is not differentiating between current direction? I also thought regerative braking didn't return much to the battery. These reported values sound substantial. Clearly I need to read up on it.

I'd assume wheellog does - if the wheel transmits it. Like the 9B1 E+. KS1xA/B/C imho don't, KS16S does, but unfortionately @JumpMaster copied the data handling code from the original KS app which cannot handle negative current values... ;(

9 hours ago, SuperSport said:

Here is an example of my MSuper when going down and then back up my driveway.  You can see it creates more going down.  And yes, my driveway is VERY steep.

2hdz40n.jpg

Additionally the wheel sends the motor current, which is higher than the battery current - the higher the lower the speed is. Could be theoretically quite a huge factor (>5) - for some real world values empirical measurements would be needed. Once the apps multiply this motor current with the battery voltage they get and show exaggerated power values!

@EcoDrift measured on his dynamometer a max power for Msuper v3 680Wh from ~2,4kw (http://airwheel.ru/test-monokoles-na-dinostende/) with imho an own current/voltage measurement! (real battery current/voltage measurent - or motor current/voltage measured. No matter what - important is that current/voltage values are taken consistently!)

6 hours ago, WARPed1701D said:

 So I'm getting a V8. Total battery power 1440Watts I think. If I experienced this level of charge from regenerative breaking I'd have cut out? I'm guessing that even of the battery isn't full the charging circuit will shut off if excess current goes in. Over 1C for example.

The protection circuits in the BMS cut off once the battery voltage gets to high (overload protection). Afaik they do not monitor the charge current and protect batteries from current greater than 1C.

The level of charge from regenerative braking is, as written before, for my KS16 about 10-15 Ampere. For a 2p configuration this would mean about 5-7 Ampere per cell of charge current! so something around 1,5-2C. For a 4p configuration as used in the KS16 it's about 2,5-4A per cell so ~0,7-1,1C.

But every wheel could handle this used regenerative current and switching to non regenerative braking differently in their firmware - and we have about no measurements for this different braking behaviours for the different wheels.

@esaj- imho the blown mosfets from braking where one of the big faults of the 9b1 P which was imho one of the main reasons why it got stopped?

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A 9B1 E+ cut over 3200W with a battery FULLY charged. And after 2 or 3sec, not before!

Tested by me with my 9B1 (Mobo 1.3.0 and Fw 1.2.2). I don't know if it's always possible with the actual Fw. 

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12 hours ago, WARPed1701D said:

This has been very informative. I'm sorry that i came at a cost to the health of @fluidfred.

Thanks for the great reply @esaj and the graphs etc @LanghamP, @Hunka Hunka Burning Love & @SuperSport.

I think there should be a crash course (bad wording I know) that covers all of this for the interested rider. Knowledge is power and this stuff is golden for helping avoid sticky situations down the road.

I've done some SUPER hard braking before that I know was applying more pressure on the motor than my driveway.  It was short, but very hard.  So far, I've never had a cut out on my wheel, but I do have one of the middle release MSuper 820Wh wheels, and I've obviously got a good one, as I so far have had zero trouble with it.  Just did a Night Ride in San Francisco with a group last night till 11:30pm.  MANY hills and hard stops.  It was a blast!  Video to come later today...

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