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Did my V8 just shutoff on me??


CaptainKBLS

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Sorry about your fall. Thankfully you are back on the wheel in no time. Bravo.

If something didn't change in the last 3 years that is "NO WHEEL IS A SAFE WHEEL". That include top branded wheels too. Hard to believe but that's the real truth. 

 

 

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4 hours ago, CaptainKBLS said:

Got the 5 bars and app says 100%

It shows ni voltage value?

then you could try some third party app like wheellog/gyrometrics or the other one i can't remember the name. They all support inmotion v8?

or you order an charge doctor and can monitor the charge process and get numbers for the battery capacity.

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11 hours ago, CaptainKBLS said:

Then i remember reading on the forum somewhere about toping off helping battery life so I recharge the next nite....also I accidently left charging over night.  Since you guys are talking about battery, I thought I'd mentioned this.  This is about the only thing that I've notice I've done different.

I've got to tell you that I've stayed clear of this thread, one guy says a low cell will cause the BMS to shut down and everyone latches on to it. Come on! That's why we used to shunt the output transistors on cheap wheels. IMHO it is VERY unlikely that Inmotion would have a BMS that does that and it is also unlikely any V8 is old enough for both cells in a pair to have failed already. but I don't know absolutely 100% for sure so I just stayed out of it.

However, when above @CaptainKBLS, tells you what he actually did nobody picks up on it, the idea the battery has gone bad keeps going.

Come on guys absolutely full battery, he brakes for a crossing and the wheel shuts down. Where have we all seen this before? Oh and what are the odds the BMS shut the wheel down due to low voltage on a cell when the battery had been very fully charged - really!

@CaptainKBLS, to the best of my knowledge no manufacturer has found a solution to the problem that braking is regenerative i.e. it puts the braking energy back into the battery pack. If the pack is totally full it has nowhere to go and there becomes a danger of overcharging the battery - which could result in a fire. So in this situation most wheels will turn off or stop regenerating (I.e. Stop braking and balancing). If you have fully charged a battery you do need to be careful about braking and downhill for the first couple of miles/km.

By the way, absolutely nobody in this forum has ever said topping off the battery helps battery life, battery life is best if the wheel is kept between 40% and 80% of charge and many people deliberately use a Charge Doctor to stop charge when current reduces to  (say) 1 Amp which will be around 90% charged, this will also prevent the braking problem (I believe) you had. However, what is frequently said is balancing only happens when the charger has reached full voltage. So you might have picked up on that. Every so often (say 10 or so charges) the charger should be left on for an hour or two after it turns green to ensure cell balancing of the entire pack occurs (I.e.all cells rise up to 4.2 volts)  obviously be a bit careful about braking after doing that.

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Would the wheel really shut off instantly from the first little overcharge, instead of at least beep for a few seconds?

Good theory though, maybe this is what happend.

Another case made for big batteries (more parallel configuration might help with absorbing overcharging without catastrophe);)

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2 hours ago, Keith said:

I've got to tell you that I've stayed clear of this thread, one guy says a low cell will cause the BMS to shut down and everyone latches on to it. Come on! That's why we used to shunt the output transistors on cheap wheels. IMHO it is VERY unlikely that Inmotion would have a BMS that does that and it is also unlikely any V8 is old enough for both cells in a pair to have failed already. but I don't know absolutely 100% for sure so I just stayed out of it.

However, when above @CaptainKBLS, tells you what he actually did nobody picks up on it, the idea the battery has gone bad keeps going.

Come on guys absolutely full battery, he brakes for a crossing and the wheel shuts down. Where have we all seen this before? Oh and what are the odds the BMS shut the wheel down due to low voltage on a cell when the battery had been very fully charged - really!

@CaptainKBLS, to the best of my knowledge no manufacturer has found a solution to the problem that braking is regenerative i.e. it puts the braking energy back into the battery pack. If the pack is totally full it has nowhere to go and there becomes a danger of overcharging the battery - which could result in a fire. So in this situation most wheels will turn off or stop regenerating (I.e. Stop braking and balancing). If you have fully charged a battery you do need to be careful about braking and downhill for the first couple of miles/km.

By the way, absolutely nobody in this forum has ever said topping off the battery helps battery life, battery life is best if the wheel is kept between 40% and 80% of charge and many people deliberately use a Charge Doctor to stop charge when current reduces to  (say) 1 Amp which will be around 90% charged, this will also prevent the braking problem (I believe) you had. However, what is frequently said is balancing only happens when the charger has reached full voltage. So you might have picked up on that. Every so often (say 10 or so charges) the charger should be left on for an hour or two after it turns green to ensure cell balancing of the entire pack occurs (I.e.all cells rise up to 4.2 volts)  obviously be a bit careful about braking after doing that.

 

Yes, I was also leary about my post.  I did not want to mislead anything as I really don't know what happened.  All I can say is I was not going very fast, was not braking hard, it was dark, it happened really really fast and I think the light went out and the wheel went limp.

Thank you guys.

For now, I am not going to ride at night and will not be weaving side to side and wearing my palm guard.

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8 minutes ago, meepmeepmayer said:

Would the wheel really shut off instantly from the first little overcharge, instead of at least beep for a few seconds?

I dont know how a V8 reacts to overcharge....a KS starts warning you by beeping or speaking "Caution, Overvoltage"...it will do that at least 20 seconds or so and than the pedals will tiltback.

Also regenerative braking  is just 1/3 effective as driving....So if you have for example full Batterie and drive 100 meters, you must drive 300meters downhill to make the Batterie full again. So i am not sure if this can be a cutoff from overcharging by just ONE breaking and that after driving a while!

 

In the end time will tell: If the Thread Opener really has one or two bad cells, a cutout will happen again....

Otherwise we will never know :-)

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30 minutes ago, meepmeepmayer said:

Would the wheel really shut off instantly from the first little overcharge, instead of at least beep for a few seconds?

Would a quality wheel like the Inmotion shut down without "at least beep for a few seconds" because one cell pair's voltage was a bit low? I REALLY think not.

I've  got a Kingsong 14C, another quality wheel, just once in 18 months of ownership has it ever shut down on me and that was when I accelerated to max speed showing off and then braked gently to do a turn. This was not long after fully charging the battery for several hours after it reached full charge as I was about to join an organised and quite long ride. This shutdown was entirely without warning the wheel simply went loose and I went flying. I'm very careful now about braking on the occasions it has to be fully charged, and tend to stop the Charge Doctor at 1 Amp - never had another problem.

As has been discussed many times before here, the logic "if I accelerate up to a speed and then brake, regeneration must surely put back less power than I've just taken out so how can I overcharge?" Is fundamentally flawed as regeneration can generate very high voltages, if the battery is close to full it isn't able to sink that power and keep the voltage down, Lithium batteries are VERY sensitive to too high a charging voltage and can quickly be damaged. This is, I think, the one occasion where it is likely the BMS, rather than the main board software, does the protecting.

I'm finding it incredible that people, with no real evidence that I can see to back it up are very willing to believe the Inmotion has a crappy Battery Management System (BMS) yet are resistant to it being a regenerative braking overvoltage failure which we have seen quite a lot of evidence for.

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41 minutes ago, Keith said:

I'm finding it incredible that people, with no real evidence that I can see to back it up are very willing to believe the Inmotion has a crappy Battery Management System (BMS) yet are resistant to it being a regenerative braking overvoltage failure which we have seen quite a lot of evidence for.

Would support Keith on this. Inmotion has the overcharge protection in place, at least by default means. I've had a chance to thoroughly examine their LVD and CE-MD documents related to V8, and the overcharge should not be the issue on the road. I'd also doubt that the amount of energy generated is enough to overcharge, as, to my memory, the amount generated by the most aggressive braking would still be lower than the charging input. 

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53 minutes ago, Keith said:

I'm finding it incredible that people, with no real evidence that I can see to back it up are very willing to believe the Inmotion has a crappy Battery Management System (BMS) yet are resistant to it being a regenerative braking overvoltage failure which we have seen quite a lot of evidence for.

Keith, i guess nobody said that it's a crappy BMS....

I even pointed out that the V8 has some Kind of communication between BMS and board....that GW/KS do not have.

Whatever we think about that fall.....real evidence is nowhere, not for overcharge and also not for Batteriefailure.

It's all just guessing what we do here, and like said, perhaps only time or a repeat of the same failure will lead us in the right direction :-)

So i can only hope for the thread opener that it was Overcharge, because than something like that fall will not so easy repeat again!!!

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Prehaps @CaptainKBLS can confirm how long he had been out on his wheel on the night in question. I just re-read this thread from the start and I see nothing that tells us this. All we know is that the battery was full to the brim when he left home. He did quote an average speed so this suggests it was not an immediate failure but again this is speculation. If he had been riding for 20 minutes or so, or covered 2 or 3 miles (about 10% of the V8 capacity) would overcharge still be likely? I think a key piece of evidence is missing here.

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Ok after further thoughts about what had happened, I believe this is actually my 2nd cutoff fall.

I alluded to a fall early on about a month after I got the wheel.  As I was feeling comfortable learning to ride, I was testing and playing around.  I decided to accelerate up a hill but as I got to the top of the hill I naturally did the opposite and decelerate on the downhill. The wheel wobbled uncontrollably and I brush it off as my fault.  Now thinking back and if my memory is correct, the wheel probably cutoff on me then too.

The current incident is very similar.  As I am weaving side to side across the street, I am accelerating and while approaching the intersection and seeing the headlight quickly brake.

Here's my conclusion:

THE CAUSE: It is my humble and naive opinion that the cause is the rapid acceleration followed by abrupt deceleration and braking.  It is very suspicious because when the wheel wobbles you naturally slow down't and brake.  It seems I could not do that because it's off.

THE PROBLEM: I do not know.  Although, I think you guys have very good guesses with battery, voltage/current consumption, etc.

THE FIX:  The fix is to avoid "THE CAUSE".

THE PROOF:  Right now it feels like, I'm claiming to see an alien but don't have a video. So, the best I can do is try to mount a camera to catch the problem.  It would have to have a view showing the battery LED going off and a view of the street and the wheel, showing the wheel might go limp.  Then get out there and repeat "THE CAUSE" to catch this problem.

Anyways, I strongly feel there is a real problem here and hope it is isolated to just my wheel.  I'm thinking about practicing when the wheel is off by manually pressing the off button.  I want to see if I can jump off and catch the wheel because I'm really concern about hitting bystanders if the wheel goes tumbling again.

Thank you all.

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I haven't email Jason yet.

This is kinda like when I first reported about the tire scraping.  The real proof was when a bunch of others reported it.

Marty's oscillation with the GW MSuper, he got it on video.

I'm kinda on my own until I get a video I guess besides getting input from everyone here.

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9 hours ago, CaptainKBLS said:

 I want to see if I can jump off and catch the wheel because I'm really concern about hitting bystanders if the wheel goes tumbling again

It is, for reasons it is hard to understand, massively more difficult not to faceplant if the wheel suddenly dies on you than if (say) you lose control. I think your instincts let you down. If you lose control the brain is already in "abort" mode, whereas if the wheel fails your instinct is still trying to lean forwards or backwards to control the wheel. So I doubt you will gain anything by trying to simulate a failure as you know it is going to happen and will be in "abort" mode.

The safest way to prevent the wheel doing damage to you or others is, as I've said umpteen times before, to use a loosely held strap which will prevent the wheel getting away from you. However, with the Inmotion wheels, you do have the issue of the cutoff button under the handle which you need to ensure the strap cannot accidentally operate. 

And thereby hangs a thought. If I understand correctly, if the wheel is actually running the cutoff button should not function. That would be worth testing, if you can gently lift the wheel tiliting it very carefully so it runs but does not keep accelerating until it cuts out and then press the cutoff button the wheel should not stop. Also, if the light is on, does the cutoff button also turn it off as you experienced? It occurs to me that a fault with that button or its wiring might have caused your problem, but not if it does not cutoff if the wheel is moving when it is pressed.

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11 hours ago, CaptainKBLS said:

THE CAUSE: It is my humble and naive opinion that the cause is the rapid acceleration followed by abrupt deceleration and braking.  It is very suspicious because when the wheel wobbles you naturally slow down't and brake.  It seems I could not do that because it's off.

Sounds quite like there was not enough sustained power to account for both accel and deccel current. Could easily be the inherent issue with BMS. weakened battery cells or the main board. I assume it did not happen at low charge? 

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