InMotion V8 tried to kill me Suddenly

[Jason McNeil]

2 hours ago, Chris Westland said:

newer systems have controls that heat the batteries so that the stay in an effective range (as just like EUC's, battery failure can be catastrophic).  Sure it may cost a few miles of range to heat the battery, but it would be worth it for a more reliable wheel.  

I think making a battery warming system is going to be complex, it will add weight, packaging dimensions, higher probability that the system might lead to unintended/undesirable consequences.

Education might be the best approach. Since batteries are exothermic, it is generally okay to take a Wheel from a warm environment into the a cold environment, provided the cell temperature does not dip below 10°C. Perhaps in the future the firmware can add a function to read the control-board's temperature sensor; if this is below a critical value, the software will force limp-home-mode until the temperature increases through use.

Edited March 9, 2017 by Jason McNeil

[Chris Westland]

5 minutes ago, houseofjob said:

And FWIW, both my folks own Model S's, and they clearly make noise in the garage when not in use, and temperatures are at extremes (hottest summer, coldest winter); so they are most definitely regulating battery temperature.

 

Interesting video ... Wouldn't it be great if Tesla were to offer appropriate modules for EUC's ... you could make @Marty Backe's Gotway Monster look puny ...

[Chris Westland]

2 minutes ago, Jason McNeil said:

I think making a battery warming system is going to complex, it will add weight, packaging dimensions, higher probability that the system might lead to unintended/undesirable consequences.

Education might be the best approach. Since batteries are exothermic, it is generally okay to take a Wheel from a warm environment into the a cold environment, provided the cell temperature does not dip below 10°C. Perhaps in the future the firmware can add a function to read the control-board's temperature sensor; if this is below a critical value, the software will force limp-home-mode until the temperature increases through use.

This is true though I wonder how difficult it would be to add on a relatively inefficient fix like one of the Turnigy bags wrapped around the V8 battery module, and drawing off the battery.  The specs of the Turnigy bag are:

Input Voltage: 10v ~ 13v DC
Idle Current: <30mAh
Working Current: 2A
Programmable Temp Value: 25/27.5/30/32.5/35/40/45ºC (2 button -/+ operation with LED display)
Operating Temp: -10ºC ~ 45ºC 
Dimensions Overall: 295mm x 230mm
Dimensions Lipo Cavity: 195mm x 230mm
Weight: 135g
Connector: XT-60 + Croc Clip Lead (supplied)

Certainly with a little DIY engineering, a DC-DC Adjustable Step Down Power Supply Module, and time, a doable mod.

 

[Jason McNeil]

1 minute ago, Chris Westland said:

This is true though I wonder how difficult it would be to add on a relatively inefficient fix like one of the Turnigy bags wrapped around the V8 battery module, and drawing off the battery.  

Yeah, maybe there can be a 'special cold weather edition' V8 with the warming bags installed.

[Chris Westland]

Just now, Jason McNeil said:

Yeah, maybe there can be a 'special cold weather edition' V8 with the warming bags installed.

Or perhaps e-Wheels might consider a special cold weather edition of aftermarket V8 battery.  I think you've said you provide aftermarket V8 batteries that should be pretty easy to swap out ... why not just an add on for people who think they need it and are willing to pay the ~$500 for a 2nd heated battery.

[HEC]

10 hours ago, Chris Westland said:

Or perhaps e-Wheels might consider a special cold weather edition of aftermarket V8 battery.  I think you've said you provide aftermarket V8 batteries that should be pretty easy to swap out ... why not just an add on for people who think they need it and are willing to pay the ~$500 for a 2nd heated battery.

Have you seen opened casing of the V8 battery - there is a bit of unused space there so some kind of heating electronic would fir there easily.

[LanghamP]

What are the "never ride", "not advisable but possible", and "recommended to ride" temperatures for the V8 and the V5?

[houseofjob]

1 hour ago, LanghamP said:

What are the "never ride", "not advisable but possible", and "recommended to ride" temperatures for the V8 and the V5?

See here: BU-502: Discharging at High and Low Temperatures

Per the Battery U article, optimal temp is 68 ºF for all batteries, to both promote proper ion flow, and preserve optimal cycle count.

Go higher, and performance is fine, but cycle count gets reduced.

Go lower, and internal resistance in the battery is increased, affecting proper discharge and resulting in reduced effective capacity. Also per the article, at -4ºF, most batteries will not function.

 

So, basically, from just a performance standpoint, colder weather (like ~30's (ºF) and below)  is what you really need to watch out for.

My personal tips for EUCs in cold weather:

• top up on charge every chance you can
• try to warm up the wheel every chance you can (i.e. don't keep it in a cold garage, bring it in with you)
• if you're stuck riding the EUC sub-40-50% in the cold, go slower. The wheel is in reduced capacity and potentially unpredictable; just because you can go max speed, doesn't mean you should.
• if you need to go prolonged distances in the cold, try not to go in one shot. try to plan a stop indoors somewhere warmer.

[Chris Westland]

10 hours ago, HEC said:

Have you seen opened casing of the V8 battery - there is a bit of unused space there so some kind of heating electronic would fir there easily.

Here is an idea for how you might use that space to add a heater ...https://www.rcgroups.com/forums/showthread.php?2105184-Here-s-my-LiPo-heater-box  or ...http://www.f5b.co.uk/equip/batteries/lipo-battery-heater/

 

 

Edited March 10, 2017 by Chris Westland

[charlesrg]

8 hours ago, houseofjob said:

See here: BU-502: Discharging at High and Low Temperatures

Per the Battery U article, optimal temp is 68 ºF for all batteries, to both promote proper ion flow, and preserve optimal cycle count.

Go higher, and performance is fine, but cycle count gets reduced.

Go lower, and internal resistance in the battery is increased, affecting proper discharge and resulting in reduced effective capacity. Also per the article, at -4ºF, most batteries will not function.

 

So, basically, from just a performance standpoint, colder weather (like ~30's (ºF) and below)  is what you really need to watch out for.

My personal tips for EUCs in cold weather:

• top up on charge every chance you can
• try to warm up the wheel every chance you can (i.e. don't keep it in a cold garage, bring it in with you)
• if you're stuck riding the EUC sub-40-50% in the cold, go slower. The wheel is in reduced capacity and potentially unpredictable; just because you can go max speed, doesn't mean you should.
• if you need to go prolonged distances in the cold, try not to go in one shot. try to plan a stop indoors somewhere warmer.

I learn that the hard way.

It would have been easy for InMotion to detect temperature and reduce the max speed and even put a message on the speaker, low temperature detected, reducing speed.

That's why I wish a US brand would make a EUC, that would have so much more thought involved.

I've e-mailed InMotion multiple times, have messaged all their ambassadors in their app and no one was able to help to get me the logs. It really sucks

[Hunka Hunka Burning Love]

How far into your ride were you?  I wonder if you had been riding for some time that the BMS cut power to help protect the cells due to a low voltage drop.  Cold temperature has a big impact on batteries.  I remember using my old digital camera which normally took 200 photos per charge ended up taking only about 50 outside in -15C weather.  It would just shut off suddenly without any warning and didn't even retract the lens in time.  It seems that the power drop off occurs much faster the colder the batteries get so you have to factor that in even with full charge.  The power cut could be so quick that the control board doesn't have any time to issue a warning.

How old is your wheel?  One other possibility might be that you could have a weaker cell in the pack that is more affected by the cold so it cut out sooner.  I'm not sure if one cell being low is enough to make the BMS cut things off, but I remember with other people's aging battery packs that failed it was due to an unhealthy cell or cells aging.  Maybe with future smart batteries they can monitor each cell's charging and discharging rates and be able to warn the control board that failure is imminent to avoid rider injury.

[Kroy]

@charlesrg
It sounds like you are talking of one specific incident rather than the experience of a full ride.
However, I've had a rather disturbing ride today which resulted in nearly coming off a couple of times.

I know very little about batteries but I'd be surprised if the temperature you mentioned would cause a problem mid-ride, equally your app diagnosis did not help.
What is your tyre pressure?

I suspected my pressure wasn't right & found it to be 1 bar as opposed to the 'factory set' 2.8. It certainly backed up my issue of wanting to veer off when the ground wasn't perfectly flat & then a struggle to get it back again.
I pumped the tyre up but decided to stop at 2.5 bar because there seemed to be a big difference compared with the previous 1 bar.  The ride home was different in that the wheel was almost too responsive & felt twitchy - I've had this before when there was too much air in the tyre. 

I'm suspicious that there is an unknown issue with my V8 but at the moment, I'm still considering the tyre pressure - unless anyone has any other thoughts?!

[Villac]

In the extreme cold (USA, mind you, not Finland!) I note that my batteries and tire pressure are unpredictable. I warm the EU up inside, I check pressure frequently, and I accelerate/decelerate gently, riding with gear ready for the fall! 

[charlesrg]

I'm not sure if the V8 temperature sensor is close to the batteries or close to the CPU. I took a measurement today after 10 minutes riding at -2 celsius and the app showed 14 celsius temperature.

InMotion should have a temperature sensor that gathers battery temperature or outside air temperature and change the speed limiter. In my view that's a huge safety feature.

With my fall I didn't brake bones, but I've been exercising about 8 hours a week. If it happened with me 6 years ago I would probably have a broken arm, lost knee cap and with a head/face injury.

[Pagsy]

Glad that you are ok after your fall.
I would guess that what happened is an overlean situation
I'm in NYC and have a V8 that I commute with as well. I have been riding EUC for 3 winters already.
I used to ride by cold temperature as low as -10 celcius.
I never lean to accelerate and I never had any problem with my V8.
I found inmotion to be the most reliable brand in EUC world ( I had 9bot, IPS, airwheel and tried some others). When it is cold I pay attention to never change my speed suddenly, ride should be smooth.

I have another v8 that has a battery issue, but it always tilts back and slowly stops before giving up.

[steve454]

5 hours ago, Pagsy said:

I never lean to accelerate and I never had any problem with my V8.
I found inmotion to be the most reliable brand in EUC world ( I had 9bot, IPS, airwheel and tried some others). When it is cold I pay attention to never change my speed suddenly, ride should be smooth.

It seems that gradual and smooth causes less problems,  especially at higher speeds.  That is good advice.

[LuckySXM]

19 mph at 200 lbs in cold weather = crash. Nothing wrong with the wheel.

Can do 19 mph doesn't mean should do 19 mph everyday in any conditions. Recipe for failure.

Sorry for your crash, but please tune down max speed to something the wheel can do safely in sustained usage.

[DavidM]

Hello people, I reply to this message thread because today I experienced the same thing with my V8. I did more than 1000 km with it so far without a problem, but today, as in my worst nightmares, it turned back against me: the power cut off for no reason at almost full speed (probably around 25km/h?). 

This is really scary... It would have happened after 200 km with the wheel or less, I think I would have broken my neck, but being experienced I was able to start running (faster than I ever did) and fell on the side of the road on a square meter of grass...

I think I was accelerating strongly but it's not the first time for sure, and certainly not a good reason...

The low temperature can't be the problem because I live in... Singapore (must be 30 degres celsius - 86 F, and the internal temperature as indicated in the app is 39 C - roughly 100 F).

Did the diagnosis in the app: sensors ok. Uploaded the error log: no idea what it can be used for...

I feel I can't trust the wheel anymore... To be honest, I think it happened another time, when starting with the wheel at the subway exit: eventhough the wheel was on in the subway when I was pushing it with the trolley, when I put the trolley back in and stepped on the pedals I fell because the wheel had turned off... I wasn't quite sure of what happened and thought that I might have turned it off without noticing while pushing back the trolley handle... but after today's incident, I think it may have been the same kind of random shutdown...

 

Among the assumptions for the root cause, I have been thinking about the button under the handle of the wheel which is made to disable the drive when you have to lift the wheel: very practical, but what if, after being used so many times, the button was becoming.... capricious...

Not sure what to do now... A checkup at a local professional service provider for sure!

Any ideas / feedback welcome!

[Keith]

1 hour ago, David Marchesseau said:

Among the assumptions for the root cause, I have been thinking about the button under the handle of the wheel which is made to disable the drive when you have to lift the wheel: very practical, but what if, after being used so many times, the button was becoming.... capricious...

I think we would need to know more about what you actually mean by "power cut off"? Was the wheel dead on its side? What did you need to do to get it going again? Did it beep?

As to the button, I'm fairly sure it isn't hard wired into the power, if the wheel is going at any speed the firmware should ignore it. This is something you might want to test at a safe speed, but I would be surprised if that is the problem.

Edited September 16, 2017 by Keith

[Chriull]

2 hours ago, David Marchesseau said:

...the power cut off for no reason at almost full speed (probably around 25km/h?). 

...

I think I was accelerating strongly but it's not the first time for sure, and certainly not a good reason...

...

Any ideas / feedback welcome!

Sorry - but this could easily be just a "normal" overlean... It's not a "good" but a valid reason...

You were near max speed and accelerated...

Could be, that by your experience and confidence it was just a bit more like before, maybe combined with a small incline or bump... (Edit: and/or maybe the battery a bit more depleted)

If you'd have some logs like from for example the wheellog app one could analyze it further and maybe find the valid (real) reason.

Edit: ps: strongly accelerating near max speed is in any case a bad idea, since it can kead very very easily to such an overlean.

Edited September 16, 2017 by Chriull

[WARPed1701D]

3 hours ago, Keith said:

As to the button, I'm fairly sure it isn't hard wired into the power, if the wheel is going at any speed the firmware should ignore it. This is something you might want to test at a safe speed, but I would be surprised if that is the problem.

The kill switch is disabled at any speed over around 5 kph. This can be easily tested by walking quickly with the wheel, app open to monitor speed, and keep pulling on the switch until it stops working. No need to ride and risk falling off. Knowing this I now ride with a tether and the kill switch enabled. Zero problems.

[DavidM]

I tested it and indeed it is disabled when riding

[DavidM]

11 hours ago, WARPed1701D said:

The kill switch is disabled at any speed over around 5 kph. This can be easily tested by walking quickly with the wheel, app open to monitor speed, and keep pulling on the switch until it stops working. No need to ride and risk falling off. Knowing this I now ride with a tether and the kill switch enabled. Zero problems.

I tested it and yes it is disabled when riding 

[DavidM]

15 hours ago, Keith said:

I think we would need to know more about what you actually mean by "power cut off"? Was the wheel dead on its side? What did you need to do to get it going again? Did it beep?

As to the button, I'm fairly sure it isn't hard wired into the power, if the wheel is going at any speed the firmware should ignore it. This is something you might want to test at a safe speed, but I would be surprised if that is the problem.

What I mean by "power cut off" is that the drive simply stopped: like powered off. I was going straight on the road, I had the reflex to put a leg forward and started to run but with the speed I was not really running, just trying to avoid falling, I must have looked like someone trying to do a Long jump at the Olympics. I knew I would fall in the end, and saw that on the side of the road where some cars where parked there was a bit grass and was able to fall there. Result is only scratches (knee bleeding, elbow...) but nothing bad.

The wheel is fine (although scratched especially on one side). I was lucky there was no car on the road at that particular moment.

the wheel did not bip, but I switched off the sounds: for me feeling the wheel tilting is enough, I don't like too many noises.

To start the wheel again I just had to switch it on again, as if nothing had happened. I went back on it but drove slowly as you can imagine.

youn are right about the button... 

[DavidM]

15 hours ago, Chriull said:

Sorry - but this could easily be just a "normal" overlean... It's not a "good" but a valid reason...

You were near max speed and accelerated...

Could be, that by your experience and confidence it was just a bit more like before, maybe combined with a small incline or bump... (Edit: and/or maybe the battery a bit more depleted)

If you'd have some logs like from for example the wheellog app one could analyze it further and maybe find the valid (real) reason.

Edit: ps: strongly accelerating near max speed is in any case a bad idea, since it can kead very very easily to such an overlean.

Hi Criull,

I don't know about you but I would expect my wheel to NEVER shutdown when I drive it, what ever I do.

One thing is true: the battery was Low.

I downloaded the log in the Inmotion app but I don't know what to do with it, it is not accessible. It must be on Inmotion cloud, now, and I suspect it is only meant for after sales Engineers to check. I will contact them to see.