KS 16s first crash

[mcsmiley]

FIrst, want to thank everyone on the board whose advice I leaned on heavily when choosing what wheel to buy.  I'm a bit above 50 years old, 6'3", 225 lbs and in decent physical condition, so wanted to ensure I bought a reliable wheel that wouldn't be taxed by my weight and have decent speed capability.  I've had it since mid-June, and already have about 600 miles on it, and frankly was getting a bit obsessed about finding opportunities to ride it.  I've been riding ~6 miles to/from the train station commuting to work each day, and really found it to be a great way to clear my head.  On good (perhaps prophetic) advice from members here, I always wear a helmet and wrist guards, and in fact, even rigged WheelLog to a Pebble Watch velcro'ed to my wrist guard.  Maybe I was getting a bit cocky.

I have the wheel set to experienced mode, alarms set to 19/20/21 mph with tiltback at 22.  I've gotten pretty good at hovering about 18 mph, only occasionally bumping 19/20 mph enough to get a beep.  I've hit tiltback a few times (to my sudden surprise), usually while accelerating away from a stop, but never enough to even come close to a crash.  Again, was seriously enjoying this thing.

Until last Thursday morning...  

I was cruising along about the 5 mile point of my ride to work, on a clear day about 7:30 am and 70 deg F.  While I'm in Denver Colorado, the route is fairly level with about 75 ft of elevation change over the entire route. The battery had started out around 90%, and I usually finish the day around 55%, so I assume I was somewhere in the low 70% range.  I had been pushing 1 or 2 beeps most of the ride, perhaps 1 mph faster than my normal pace, but hadn't hit any tiltback, and think I was going about 19 mph when suddenly...I found myself face down on the pavement wondering what the heck had just happened.  Oh, and it hurt like hell.

The wheel had just stopped.  No tiltback, no wobble, no warning except the impending asphalt headed for my face.  Fortunately, perhaps as a result of training during my misspent youth, I instinctively tucked into a parachute landing fall and took the impact on my right side rather than in my face.  Congratulations - welcome to the "those who have" club.  I managed to get myself over to the curb, sit in the grass, remove my helmet and backpack, and beg my girlfriend to come pick me up.  Fortunately, no serious head impact (thanks helmet), though marks on the helmet look like it took a pretty good hit.

Surveying the scene, the wheel was laying on its side, with the tire stopped (not spinning), with green LED's lit like normal.  Assuming I'd hit something massive, I looked but saw nothing but perfectly smooth pavement with no possible culprit.  Other than being very sure it hadn't "tilted back" on me, I had no idea what caused the wreck.  For those familiar with wakeboarding or snowboarding, it felt every bit like "catching a toe side" as the impact was that sudden.

Fortunately, despite my agony, the trip to the Emergency Room showed no broken bones, only a number of sections of scraped skin and a severe sprain to my right shoulder.  The now yellowing bruise down the front of my shoulder tells me my backpack took a lot of the fall but tried to wrench my right shoulder from the socket.  Regardless, this should have been a lot worse, and I'm damn thankful for safety gear and a heck of a lot of luck.  Perhaps it's restored a little humility.

At any rate, I'm now eager to "get back on the horse" that threw me.  But I don't want to just assume it's safe to ride.  I've been reading through all sorts of posts here, and I'm fairly convinced the wheel shutdown on me, either due to prolonged aggressive riding at my weight, or some failure of either a battery cell or a component on the control board.  I've tried to recover the log from WheelLog, but in my somewhat muddled state of mind after the wreck, didn't think to specifically save the log.  I've looked on the phone's drive and can't find a log file from that date.  Yet the very reason I bought the Kingsong was the reputation for electronics where such behavior didn't happen.

I turned the unit on, and while the Kingsong app said 72% battery, WheelLog says 60% (don't remember a discrepancy before).  The voltage read 61.5V which seems low to me as I think my ChargeDoctor duo set to 66.1v yields about 91%.   I have to do some surgery to the unit anyway to replace the rear fender, which detached in the impact, so I'm comfortable with digging into the unit.  

Looking to you all for recommendations on things to test before riding it again, as I most certainly do not want to repeat my recent flight (actually, it was the landing that hurt, the flight itself was uneventful though woefully short).  Would have at least appreciated an "Ok 3-wire".     

Thoughts?  Thanks in advance.  And wear your safety gear.

 

McSmiley

 

[US69]

@mcsmiley

First: Sorry for your Fall, but at least good that no serious injuries happen to you!

For the wheel: You are right, normally KS wheels are meant NOT to cutout of the blue.

So i would suspect that while riding perhaps one or two cells decided to die. When you have someone that is a bit familiar with electronics, i would advise to check both batterypacks and each of the cells by measuring on the BMS. Or i would at least do some stress tests like pushing the wheel in a safe environment, like for example leaning yourself against a wall....triggering some higher amps and see how the wheel behaves! 

 

 

 

[meepmeepmayer]

Oh wow. Luckily your injuries aren't more serious. Helpful story! 

Can you tell whether this was a cut-out (an instant electronics failure making the wheel stop and rotate forwards on the spot) or an overlean (overpowering the wheel, a bit less instant). Sounds like the former, especially if you got no warning whatsoever. This should not happen! It's the EUC nightmare scenario.

If the tire isn't locked in place, does not sound like a board failure (the cause of most cut-outs, as rarely as these happen) but the battery is defect?

Anyways, don't ride it at all, and in doubt, be in contact with your dealer. And maybe have your dealer do the work. You shouldn't have to repair such a new wheel that should never have failed like this in the first place.

Finally, the holy trinity of protection is wrist guards, helmet and knee guards, so complete that set

[esaj]

8 hours ago, mcsmiley said:

I turned the unit on, and while the Kingsong app said 72% battery, WheelLog says 60% (don't remember a discrepancy before).  The voltage read 61.5V which seems low to me as I think my ChargeDoctor duo set to 66.1v yields about 91%.   I have to do some surgery to the unit anyway to replace the rear fender, which detached in the impact, so I'm comfortable with digging into the unit.  

Do you always charge it to 66.1V? The cells in the packs need to be balanced every now and then (say, every 10-20 charges or such) by charging the entire pack all the way to full, otherwise one or more cells can be left at lower voltage and will drop faster than the others. Depending on the battery BMS (Battery Management System, a circuit board inside the battery pack), it can cut all power to protect the battery if single cell dips below critical threshold (which could be something like 2.5...3V per cell).

Since you have a Charge Doctor, you can use that to check the full balancing charge at times; allow it to charge to full voltage and leave the charger running until the current drops to very low values (the charger light will already show green far before that), like 0.05A or even less. It appears the balancing only starts when the voltage is already almost full, so while partial charging is otherwise good for the longevity of the battery cells, a balancing charge is still required every now and then.

[US69]

8 hours ago, mcsmiley said:

and while the Kingsong app said 72% battery, WheelLog says 60% (don't remember a discrepancy before).  The voltage read 61.5V which seems low to me as I think my ChargeDoctor duo set to 66.1v yields about 91%.

KS app and wheellog Show a different percentage...the "gap will get bigger between the apps the more the voltage goes down.

Reason is that wheellog and also DarknessBot are using a different "empty voltage" number for 0% then the KS app. 

16 minutes ago, esaj said:

Do you always charge it to 66.1V? The cells in the packs need to be balanced every now and then (say, every 10-20 charges or such) by charging the entire pack all the way to full, otherwise one or more cells can be left at lower voltage and will drop faster than the others. Depending on the battery BMS (Battery Management System, a circuit board inside the battery pack), it can cut all power to protect the battery if single cell dips below critical threshold (which could be something like 2.5...3V per cell).

Yeah, i Always charged to 90% and never using 100% the cells might run different after a Long time.

While here in this case, the Wheel still showing 60-70%, the gap would have to be enormous.

 

As cutouts "of the blue" are not supposed to happen -whatever brand the Wheel is- i would strongly advise to check the battery/cells…..

[mcsmiley]

10 hours ago, US69 said:

@mcsmiley

 

 When you have someone that is a bit familiar with electronics, i would advise to check both batterypacks and each of the cells by measuring on the BMS. 

 

 

 

Crud...time to remember the Electrical Engineering education from so long ago... (I should be fine).  If I go into the batteries with a voltmeter on a fully charged pack, should I expect exactly 1.5 v on each of these cells, 3V or "something similar"? I believe the cells are Sanyo in the 840 Wh, or at least that's what the sticker says.  Should I dig through previous posts looking for an tutorial on measuring on the BMS?

Will try the balancing trick recommended as well, though in the first month and a half of ownership (prior to reading the negatives of doing so), I charged to 100% every time.  Then, upon becoming better educated on the subject, bought the Charge Doctor and have tried to keep it about 90% since.  

 

Greg

[Lutalo]

On 8/28/2018 at 11:17 PM, mcsmiley said:

I turned the unit on, and while the Kingsong app said 72% battery, WheelLog says 60% (don't remember a discrepancy before).  The voltage read 61.5V which seems low to me as I think my ChargeDoctor duo set to 66.1v yields about 91%.   I

I wanted to add that about a year ago my son took a fall similar to yours, but his was definitely due to an electronic failure. His motherboard burned out while riding. When he turned off the wheel it would not roll. When we lay it on the ground and attempted to turn the wheel it would not move.

This is one clear way to diagnose a motherboard burnout. In my case, as I have previously described, it was just me overloading the machine. In each instance I got back up and kept riding with no problem other than my pride and injuries. My sons wheel was unrideable after his fall.

It sounds like your wheel may not have a burned motherboard, but the battery has had some sort of malfunction.

I suspect it might be more than the brown out scenario I described because I think you said that you had a 70+% charge when you began your ride. When my incident happened I was somewhere around 30%. 

I hope this helps, I am not a tech expert but I can share my experiences riding the wheel. The good thing is that you are uninjured and in good spirits ready to ride again. 

Edited August 30, 2018 by Lutalo

[steve454]

1 hour ago, mcsmiley said:

Crud...time to remember the Electrical Engineering education from so long ago... (I should be fine).  If I go into the batteries with a voltmeter on a fully charged pack, should I expect exactly 1.5 v on each of these cells, 3V or "something similar"? I believe the cells are Sanyo in the 840 Wh, or at least that's what the sticker says.  Should I dig through previous posts looking for an tutorial on measuring on the BMS?

Will try the balancing trick recommended as well, though in the first month and a half of ownership (prior to reading the negatives of doing so), I charged to 100% every time.  Then, upon becoming better educated on the subject, bought the Charge Doctor and have tried to keep it about 90% since.  

 

Greg

Not sure but I think fully charged is about 4.2 volts per cell.  But IIRC you should check each cell on a less than fully charged pack so that any cells that are weaker will stand out with lower voltage than all the good cells.  In other words, you hope that all the cells read very close to the same voltage, which would mean the pack is probably good, at least the cells anyway.

I'm not a battery expert, I am just trying to remember things from other threads.

[esaj]

20 minutes ago, steve454 said:

Not sure but I think fully charged is about 4.2 volts per cell.  But IIRC you should check each cell on a less than fully charged pack so that any cells that are weaker will stand out with lower voltage than all the good cells.  In other words, you hope that all the cells read very close to the same voltage, which would mean the pack is probably good, at least the cells anyway.

I'm not a battery expert, I am just trying to remember things from other threads.

This is a good advice, if all the cells are charged & balanced to full, you can't tell the bad ones based on voltage alone. The typical "normal" range for the types of lithium cells the wheels use are about 3.3-4.2V, depending on charge state. Some wheels may allow discharging to 3V, below that the cell is usually considered "overdischarged". Small variations between cell voltages is to be expected (like 0.0x volts), but if there are larger differences (hard to say what would be the "cut off point") and one or more cells are, say, more than 0.1V lower than others, they may have degraded (less total capacity, higher internal resistance, drop voltage faster under load).

EDIT: Oh, and the usual, be careful with the battery packs, they contain a lot of energy:

 

 

Edited August 29, 2018 by esaj

[meepmeepmayer]

Guys, it's a 2 month old wheel. He should return it or have it repaired by the dealer, not disassemble a battery pack.

Where did you buy from @mcsmiley?

[mcsmiley]

Alas, I bought it used, from a guy who had it a month and managed to both run into a mailbox and burn a skid mark in his apartment carpet after picking it up and getting the overspeed.  He managed that while putting less than 1 km on it and the hatred was evident when I took it off his hands.  The only reason I bought used was that Ewheels was back ordered for about a month and I didn't want to wait.  I've bought parts and my charge doctor from Jason, so I hope that mitigates the sin.  Certainly he's been nothing less than gracious when I've called his shop.

 

I really am an electrical engineer, so it's a pretty safe incursion for me to check a battery pack.

 

Will report back on what I find.

 

Mcsmiley

 

Edited August 30, 2018 by mcsmiley
Typo

[Chriull]

19 minutes ago, mcsmiley said:

I really am an electrical engineer, so it's a pretty safe incursion for me to check a battery pack.

You have such a shrink plastic to enclose the battery afterwards and have it then watertight again?

 

6 hours ago, meepmeepmayer said:

Guys, it's a 2 month old wheel

... So it would be quite some bad luck to have already degraded/unbalanced batteries?! Should be just from bad storage in a warehouse or a bad cell from the manufacturer?

Edited August 30, 2018 by Chriull

[maxkan]

22 hours ago, US69 said:

"while riding perhaps one or two cells decided to die" - How is that even possible?? The guy only had it since mid June

 

[US69]

4 hours ago, maxkan said:

How is that even possible?? The guy only had it since mid June

First of all this is just a thought and something that would match to the Situation, but it is by far not confirmed.

And to the General Question: Battery cells can fail!(Like all electronics can do btw) Has Nothing todo with age...and it is for sure seldom, but it CAN happen.

[US69]

11 hours ago, meepmeepmayer said:

Guys, it's a 2 month old wheel.

And as you see who knows what allready happens to it :

4 hours ago, mcsmiley said:

from a guy who had it a month and managed to both run into a mailbox and burn a skid mark in his apartment carpet after picking it up and getting the overspeed. 

 

[maxkan]

14 hours ago, US69 said:

And to the General Question: Battery cells can fail!(Like all electronics can do btw) Has Nothing todo with age...and it is for sure seldom, but it CAN happen.

We need some redundancy then, to reduce a probability of failure.

You're a KS representative, right? Let them know we need a device that is not only fun but safe as well.

And its good for the business. Each of those accidents reduce KS sales

[US69]

1 minute ago, maxkan said:

We need some redundancy then, to reduce a probability of failure.

You're a KS representative, right? Let them know we need a device that is not only fun but safe as well.

And its good for the business. Each of those accidents reduce KS sales

The batteries are allready the only part in an EUC  that are kind of redundance, as in such wheels they are setup at about 4 times paralell!

That still doesnt help if something fails!

And we talk about ALL brands here and not only Kingsong.

If you before had the idea that EUC riding is -no matter what brand- a kind of safe, i am sorry for destroying that illusion....

KS is trying to make their wheels as reliable as possible...and i would say their record is relying on statistics of resellers better than other brands!

But unfortunately an EUC with redundancy isnt invented yet. The -bitter- truth is...if something fails on your EUC-  battery, electronics, wiring, connector, mosfet, hall sensor, whatever, you probably will fall. 

So my intention here is just to get a better understanding of what might have cause the fall, so that the user can take the necessary steps that it hopefully will not happen again. 

 

 

[yasbean]

On 8/30/2018 at 5:23 PM, maxkan said:

We need some redundancy then, to reduce a probability of failure.

You're a KS representative, right? Let them know we need a device that is not only fun but safe as well.

And its good for the business. Each of those accidents reduce KS sales

If you want redundancy, I am afraid you are going to need a second wheel.  I suppose you could put one wheel in front of the other, and maybe even attach a seat to a metal frame that holds the two wheels in place.

[Danchase]

On 8/29/2018 at 10:37 PM, mcsmiley said:

Alas, I bought it used, from a guy who had it a month and managed to both run into a mailbox and burn a skid mark in his apartment carpet after picking it up and getting the overspeed.  He managed that while putting less than 1 km on it and the hatred was evident when I took it off his hands.  The only reason I bought used was that Ewheels was back ordered for about a month and I didn't want to wait.  I've bought parts and my charge doctor from Jason, so I hope that mitigates the sin.  Certainly he's been nothing less than gracious when I've called his shop.

 

I really am an electrical engineer, so it's a pretty safe incursion for me to check a battery pack.

 

Will report back on what I find.

 

Mcsmiley

 

Did you ever get to take a look at it?  I just took a crash on my way to the train station in Denver as well.  Its strange how similar the circumstances are.  I’m riding a KS16D, been riding daily several miles/day for almost 2 months and have a very good feel for how it rides and handles.  Today just after I left home I was accelerating quickly and it felt like it just turned off and was confronted with asphalt very quickly.  No warning, bumps or anything.

[Lutalo]

On 8/30/2018 at 8:55 PM, US69 said:

The -bitter- truth is...if something fails on your EUC-  battery, electronics, wiring, connector, mosfet, hall sensor, whatever, you probably will fall. 

That is indeed a bitter truth about riding EUCs. The best counter-punch to wheel failure is safety equipment.

[See6]

Not sure if this is relevant...  Does the KS16 have an auto off when you pick it up?   If so, have you checked that sensor? 

[RockyTop]

11 hours ago, See6 said:

Not sure if this is relevant...  Does the KS16 have an auto off when you pick it up?   If so, have you checked that sensor? 

No. That is a new feature on the 18L. .... But depending on how the new software is written you can false fire an unused input. ( power drop or spike) Even then I don’t think it would permit the senor to shut the wheel off at speed.

Edited September 29, 2018 by RockyTop

[Lutalo]

On 9/28/2018 at 10:59 AM, Danchase said:

Did you ever get to take a look at it?  I just took a crash on my way to the train station in Denver as well.  Its strange how similar the circumstances are.  I’m riding a KS16D, been riding daily several miles/day for almost 2 months and have a very good feel for how it rides and handles.  Today just after I left home I was accelerating quickly and it felt like it just turned off and was confronted with asphalt very quickly.  No warning, bumps or anything.

I want to believe. Maybe, the area around the train station is built on an ancient burial ground and the restless spirits don't like EUCs - just a thought ??

Edited September 29, 2018 by Lutalo

[Chriull]

On 9/28/2018 at 4:59 PM, Danchase said:

Did you ever get to take a look at it?  I just took a crash on my way to the train station in Denver as well.  Its strange how similar the circumstances are.  I’m riding a KS16D

D? Never heard of this version - just A/B/C and S. You know whats the specifics of a D?

On 9/28/2018 at 4:59 PM, Danchase said:

, been riding daily several miles/day for almost 2 months and have a very good feel for how it rides and handles.  Today just after I left home I was accelerating quickly and it felt like it just turned off and was confronted with asphalt very quickly.  No warning, bumps or anything.

That's just the physics of EUCs - not really intuitiv but understandable: 

 

[meepmeepmayer]

5 hours ago, Chriull said:

D? Never heard of this version - just A/B/C and S. You know whats the specifics of a D? 

Which letter is right next to the D on a keyboard? Sometimes instead of an exciting explanation, there's only a disappointing one.

It would be a good time for a 2000W motor, 45+ kph, lift button, possibly 3 inch tire update of the KS16. But alas...