[WARNING] Gotway Nikola 100v 1800WH Battery Fire

[Chaindrop]

8 hours ago, WI_Hedgehog said:

Charge fully (100% = 4.20V, engages the balance circuits),

Ohhh. I remember reading somewhere that it's healthier for the batteries to just charge only up to 90%, and only charge it to 100% once a month. I guess I need to change my ways.

[alcatraz]

7 hours ago, Chriull said:

From the current BMS analysis done till now the BMS balancing resistors discharge all overcharged cells downto ~4.2V again!

 

That's assuming the bms works. If only there was a way to know.

I've had 40% of cells at 4.25v and the bms does nothing. Damage is unlikely to come from that but my point is, we ultimately don't know. Who knows what will happen 2y and 5000km later?

Bms failure vs cell failure I think is on a scale of 100 to 1 , but we only see the latter.

[Lefteris]

I'm also a Nikola Plus 100V with 21700 cells owner, since March.

And i'm experiencing a problem for the last 1,5 months i haven't heard the fan start even once. Last weekend i opened up the wheel with @Χρήστος Γεωργαμπλοπουλος and found out that the beep-speaker was missing a screw, that was latter our assumption that i may have dropped into the double bearing side blowing fan of the Nikola Plus design cause the fan won't budge.

I've ordered 2x Fans from China, and paid extra for fast shipping cause i don't want to wait for replacement from Gotway thru my dealer, who was quick to identify the problem.
I've put 2 screws to place the beep-speaker in place and now ride everyday from work to home and back and sometimes with friends but all voice alarms of euc world and pebble alarms are on, cause i don't want to over-heat the board. When i reach 60°C i stop and let it breath for like 3-4 minutes then ride again.

If there is also a problem with my batteries, which i don't know what kind of batteries are inside, i'd like to know a way to identify that.

Official Gotway app shares no information, EUC world shares more information but not the battery cells brand. How can i find out what type of batteries my Nik+ rocks?

Thank you in advance!

[Chriull]

2 hours ago, Lefteris said:

If there is also a problem with my batteries, which i don't know what kind of batteries are inside, i'd like to know a way to identify that.

Official Gotway app shares no information, EUC world shares more information but not the battery cells brand. How can i find out what type of batteries my Nik+ rocks?

Maybe this can be identified by the serial number/production date by someone?

Or there is a sticker on the battery pack giving a clue?

Only other possibility would be opening the battery pack...

The apps have no way to identify the used cells...

Would be interesting what this problem with the first batch of panasonic cells was. And if this exchange is just some precaution or really to be recommended?

Hard to say without any more information...

[Lefteris]

At least find a way to identify which model of batteries we have inside our wheels.!

Anyone?

[Sai]

14 minutes ago, Lefteris said:

At least find a way to identify which model of batteries we have inside our wheels.!

Anyone?

I emailed them direct with my order number, date and address. begode11@kebye.com 

They got back to me within an hour. PS I bought from gotway direct. 

Edited May 31, 2020 by Sai

[Lefteris]

Thank you @Sai but i got it from a European dealer, so i contacted them about it and waiting for their response!

[PLEASE_DELETE]

Deleted.

Edited March 18 by PLEASE_DELETE

[Lefteris]

@/Dev/Null it's exactly what i'm trying to figure out, a way to identify what kind of batteries we have.

The part of recall, nothing is heard so far, or at least of me knowing.

But lets just wait a day or two and see.

[PLEASE_DELETE]

Deleted.

Edited March 18 by PLEASE_DELETE

[Lefteris]

If you have the LG ones yes you are clear, but still even with the Panasonic ones if you charge to optimal 100.8V you have all cells working.. if you see <= 98V then you need to check things out.

 

[PLEASE_DELETE]

Deleted.

Edited March 18 by PLEASE_DELETE

[Lefteris]

I just got word from my dealer

I personally have the LG batteries.

and I feel so sad about what happened to the other guys

[meepmeepmayer]

The 1800Wh MSX uses/used Sanyo 21700 cells according the the Gotway website. Are these the same as the "Panasonic" cells we are speaking of here? Because the 18650s are billed as "Sanyo/Panasonic".

Just wondering. They switched to LG M50Ts, but probably all 21700s before would be the "Panasonic" ones then? Or not?

Because no 1800 MSX has shown any problems (or any of the older "Panasonic" 1800Wh Nikolas). So why do they suspect the battery cells right from the start, after one incident?

[D3m0nzz]

A lot of speculation in the thread, when we dont even really know what the actual issue is yet. 

Let's try to wait for Jason and/or GotWay to make an official statement before we go telling people that their wheels are OK to ride. It takes a lot of money and effort for a business to organize a recall like this and I unfortunately doubt the ethics of GotWay to perform a recall on their own, unprompted by Jason. 

[davinche]

Update from Jason:

Quote

Here is an updated from late Thursday evening communication: 

1. Battery Removal Instructions: attached is an overview for extracting the battery packs from your Nikola.
2. New Packs Schedule: In order to accelerate the replacement program, we have offered to pay Gotway for prioritizing this work & will be flying in the new battery packs with a target to have them shipped out in the next 3 weeks
3. Calculating Present Danger/Risk: As to the actual/real present risk of these particular Panasonic 21700 battery packs, as there's been but a single case within production run of 500x Nikolas, over a 6 month timespan, it's not possible to say how likely, or even if, such an event will happen again; for the moment, this recall is entirely precautionary in nature.  

 

 How to: Remove and Pack Nikola+ Batteries

Hope this helps,

 

Jason

 

[davinche]

For me I think I would be more at peace if Gotway were to provide more information about the Panasonic cells:

1. Are they the same the same cells that they use in the tesla model 3

2. How were they able to source these cells?

3. What problems did they run into with these cells that caused them to switch over to the LG M50T?

Edited May 31, 2020 by davinche

[WI_Hedgehog]

20 hours ago, Chaindrop said:

Ohhh. I remember reading somewhere that it's healthier for the batteries to just charge only up to 90%, and only charge it to 100% once a month. I guess I need to change my ways.

Summary: Always Balance Charge EUC Batteries

It is true, charging to 4.0/4.1V maximum doubles the cell life. Discharging to 3.30/3.35V minimum doubles the cell life. (exact voltage depends on the cell chemistry)

The problem is we cannot currently measure cell voltage, only pack voltage. So we assume 4.0V = 80% capacity & 3.3V = 30% capacity for the pack applies to each cell, but it does not. 

As @Archee Jan Bloch correctly points out, when the battery, which is the whole pack of cells, reaches "low voltage," it is for all cells in series. We do not usually know what the voltage of each cell is. If one cell is weak the remaining cells in parallel will support it. If the battery is balance charged, more time will be spent recharging the weak cell group to bring it up to the level of the rest of the cells. The one cell will always be weak, but balancing brings things back into balance.

@Archee Jan Bloch continues saying that if the battery is charged but not balanced, the weak cell/cell group will not be fully charged, and during the next use be under more stress to perform. The weak cell(s) will get hotter, the internal resistance will go up, and the weak cell(s) will have to work even harder to supply energy, depleting the weak cell(s) even further. From observation he is correct: when I discharge a balanced pack from 4.20V average to 3.00V average, the weak cell has usually started out at rest at 4.19V, maybe 4.18V. It has to work harder than the cells at 4.20V. And honestly, this is most of the cells in the battery--only a few cells will be at 4.20V. 

At the end of the ride, the strong cells are at 3.10V, but the rest at 3.0V with some at 3.29V & 3.28V. When I recharge without balancing, the strong cells are at 4.01V, the rest at 4.00V, 3.99V, 3.88V, and usually one or two stragglers at 3.97V. These stragglers are of concern--a normal balance charge with a smart BMS would put them at 3.99V, but they are at 3.97V. On the next use, the voltage spreads out: 3.10V, 3.0V, 2.99V, 2.98V, 2.97V, 2.96V, 2.95V.

Here's where it gets interesting: recharging the second time, some cells will be at 4.1V, but the low cells of interest-the stragglers-will be at 3.93 & 3.92V. If I take the unit out for a third ride the voltage will be spread out from 3.2V down to 2.85 & 2.82V. So by not balance-charging for two charges, damage is being done to 1 or 2 cells.

This problem does not develop so fast with cells in parallel, and when discharging to 3.30V=30% instead of 3.00V=0%, but over 10 charges it can still happen. The cells that reached 2.82V will always be damaged, so if I balance charge and then keep charging to 80%, those cells or cell groups in parallel are going to continue to degrade and die. 

As @Archee Jan Bloch points out, once a cell group is dead, more strain is put on the rest of the battery both during use and during charge. Because there are so many cells we do not usually notice unless checking voltage as @Chriull alludes to. This is where the real problem comes in as @Archee Jan Bloch points out, because when the second cell group dies the remaining cells (18S in a 20S pack, or 22S in a 24S pack) get the full charger voltage, and the bleed-off circuits cannot keep up with the power supplied by the charger, especially a fast-charger! Some cells are at 0V, some cells are 4.35V, and the BMS circuitry is ready to burn up from dissipating so much energy--the charger is supplying:
4V x 20V/cell (normally) = 80V
80V over 18cells (2 dead) = 4.44V/cell

The next balance charge at 100% voltage is:
84V over 18cells (2 dead) = 4.66V/cell!

If you charge 18 cells to 4.66V/cell, then take it out and start off from a dead stop, which is very high amp draw.... The wheel has all these overcharged cells that built up spikey dendrites in them, making them effectively "little bombs." (perhaps a bit dramatic, but you should see an Remote Control (R/C) race car, heli, or plane go up in flames at 80+ MPH! THAT's dramatic!) This is why the racers that cheat by overcharging to 4.35V/cell or 4.38V/cell or heaven forbid 4.40V/cell dispose of their batteries after 2 races. Charging to 4.5V/cell would certainly be taking risks for a LiPo fire. The 4.66 volts per cell an EUC charger would put on a battery is crazy. It is for these reasons R/C people strongly warn about charging in parallel, where as EUC people do that every charge. (R/C says do not charge battery packs in parallel so you know the health of every single cell and can minimize the risk of catastrophic failure.) R/C does not use a BMS, but rather a smart charger and known discharge cycle--the smart charger is the key, which is why a Smart BMS is important in EUC use.

Not knowing individual cell/cell group voltages is why charging EUC batteries to 100% every time to balance the cells is so important, and will extend the life of the battery for EUCs. If you had a smart charger like in R/C that knew the state of charge of every cell and balanced the cells to 4.00V/cell, then it would be okay to charge to 80%.

Not knowing individual cell/cell group voltages is why EUC batteries should not be run below 3.3V/cell for safe use. It keeps the cells that have lower voltages from discharging too low, heating up too much, and aging faster than necessary. 

(I note the Segway/Ninebot miniPROs that I own have Smart Battery Management Systems that are always active and charges the batteries to 80%=4.00V/cell. If I charge to 100% full the BMS has charged and balanced the cells to 4.00V/cell=80%. Since the Smart BMS is always active, even when the unit is off, the batteries should not become unsafe. I should not be able to use the board so that any cell is discharged below 2.87V (and this is what happens as far as I can tell). I do not know about their EUCs.) 

[Chriull]

@WI_Hedgehog - great post! But i'm still not convinced it's the batteries. My first guess is still a short circuit in combination with ?missing short circuit protection? causing this fire.

[alcatraz]

The larger the imbalance the longer it takes to balance.

For you that charge to 80% or do the same routine year after year. Remember that imbalances accumulate, and they accelerate with age.

There will be a point where a working bms needs more time to sort the battery out. With a new battery the balancing process could take 10min but with an old enough battery it could take 1-2 days. 

So if you've charged to 100% and left it there for 2h out of habit, that could need modification as the pack ages. You could need to modify the routine after 1y or after 5y. It depends on the total capacity vs bms balancing current, and the cell degradation rate in the particular batch of cells you have.

[Michael Tucker]

If simply charging to 80% were the problem in this particular case, replacing the battery pack would just result in another fire. If charging to 80% caused fires regularly it would be known. If charging to 100% were mandatory, from which place would we be required to get that information.

I have many wheels and many stock and fast chargers and a Cycle Satiator. When I charge any Gotway wheel to "100%", I can connect to the wheel via Gotway Official App, Darkness Bot, Wheelog, EUC World, or the read-out on the side of my Nikola, or the display on my Cycle Satiator, or the green light on a stock charger...each item reads differently. Not one of these measuring devices agrees with the other. Sometimes 100.8 or 100.1 sometimes out on a ride the difference in what the side display of the Nikola reports is off by 2 volts compared to what Wheelog will tell me. Even between stock chargers I have found some charge to 84.2 and another of the same model will charge to 83.8 on the same wheel.

I don't think charging only to 80% or 90% on a perfectly healthy battery pack connected to a perfectly healthy control board causes a fire in a wheel with so few miles on it. Why would Gotway be so quick to replace the battery pack with different cells if charging was the problem?

 

[D3m0nzz]

17 minutes ago, Michael Tucker said:

Why would Gotway be so quick to replace the battery pack with different cells if charging was the problem?

 

Exactly this^ companies don't do expensive recalls unless they know that the issue is with that particular part. Batteries are the most expensive component on an EUC. The issue HAS to be with the batteries (contrary to what many are stating in this thread)

[WI_Hedgehog]

On 5/31/2020 at 1:59 PM, Chriull said:

@WI_Hedgehog - great post! But i'm still not convinced it's the batteries. My first guess is still a short circuit in combination with ?missing short circuit protection? causing this fire.

Thank you.

I'm not convinced this fire is a charging or battery specific issue either. Having followed lots of Gotway threads I would personally want to open a newly ordered wheel and check everything over first.

Gotway's Quality Control department seems to be the Glue Gun Guy: "If I can't glue it, screw it--it's a warranty issue and we have none." 

Edited June 2, 2020 by WI_Hedgehog

[davinche]

45 minutes ago, D3m0nzz said:

Exactly this^ companies don't do expensive recalls unless they know that the issue is with that particular part. Batteries are the most expensive component on an EUC. The issue HAS to be with the batteries (contrary to what many are stating in this thread)

The battery recall as of right now is only for EWheels customers, not Gotway or other distributors AFAIK. Again, this is testament to @Jason McNeil prioritization of customer safety over profits. So far I am the only one who experienced this problem, so it could very well be the case that I was the only one unlucky enough to end up with a lemon. But the consequence was serious enough for Jason to work with Gotway on the recall.

Of course as I mentioned before in a previous post, I would like to see Gotway provide us with information about the panasonic batteries and what were the specific problems they ran into that made them switch to LG M50Ts.

[.....]

1 hour ago, davinche said:

The battery recall as of right now is only for EWheels customers, not Gotway or other distributors AFAIK. Again, this is testament to @Jason McNeil prioritization of customer safety over profits. So far I am the only one who experienced this problem, so it could very well be the case that I was the only one unlucky enough to end up with a lemon. But the consequence was serious enough for Jason to work with Gotway on the recall.

Of course as I mentioned before in a previous post, I would like to see Gotway provide us with information about the panasonic batteries and what were the specific problems they ran into that made them switch to LG M50Ts.

The LESS gotway says about this, the less likely they will be forced to accept fault. Im not saying it is or isnt their fault, but dont hold your breathe waiting on an explanation.  An explanation can be construed as accepting fault, or even recognizing the problem. IN lawyer speak, neither of those two things are a benefit to the bottom $$ of the company. I do feel much assurance knowing that I have the luxury of being within Jason's selling territory. I do hope things like this are remedied at minimal end expense to him for sure!

Edited June 1, 2020 by ShanesPlanet