[WARNING] Gotway Nikola 100v 1800WH Battery Fire

[davinche]

Note: The model that caught fire was the first batch of Nikola 100V 1800WH Panasonic NCR21700A. I have never crashed my Nikola nor have I mistreated it in any way. Over the span of 5 months, I've only used it to commute to and from work (~7.5 miles each way). I did have a fast charger from ewheels (the Nikola did not come with a charger), but I have never charged it with > 3A or to 100% (used the 90% setting on the fast charger). Edit: I've charged it to 100% once or twice in the beginning while I was configuring the charger. Shortly after, I read that charging to 100% is not recommended in order to preserve battery life which is when I decided to switch to 90%. All charges besides the initial first couple of charges were done via the 90% setting. AMP-wise I have always only used 3A.

Below is official communication from EWheels. Jason asked me to withhold posting on the forum until he had time to communicate with Gotway and develop a plan of action. Many people in the EUC community praise EWheels for genuinely caring about the his customers and the community. I am glad I purchased my wheel through Ewheels and the communication from the email (below) was the evidence I needed that I bought from a good distributor.

One minor correction I want to make to the official email is that it didn't catch on fire immediately after turning on. I walked it to a parking lot near my place (so it was already on). When I got on it, it immediately shutoff and threw me off the wheel. It was only then after mysteriously powering off did the wheel go into thermal runaway and the wheel caught on fire.

Anyways, below is the official communication. I am posting to raise awareness for those that might not have purchased through a distributor. Once again my model was the PANASONIC NCR21700A cells.

Quote

Good evening,

 

We received notice from one of our Customers that an 100v Nikola 1800Wh with Panasonic 21700 cells recently caught fire. 

 

Here is what we know so far:

• A Nikola+ 1800Wh from the first batch to use Panasonic 21700 cells caught fire a few minutes after powering on
• It was reported this wheel had not sustained damage due to an accident, nor had it undergone modifications or repairs
• The owner reports that they routinely only charged to 90% at 3A.
• Fortunately, the fire occurred in an empty outdoor parking lot, and no one or property was harmed 

If you are receiving this email, you purchased a Nikola+ 1800Wh that contains 21700 cells of the same origin as those involved in this incident.

 

Even though this was a single isolated incident, within a six month time frame, the safety of our Customers is our highest priority, and will be carrying out a targeted recall of the battery packs in this production run. These Nikola+ 1800Wh/100V were shipped to Customers between December 19th, 2019 to April 16th, 2020.

 

Considering the potentially grave consequences of a battery fire, we are committed to prioritizing above all else the safety of our Customers.

 

Here is our plan of attack:

• Gotway have been immediately notified 
• We have identified and are sharing this information with our Customers who received a Nikola+ 1800Wh which contains the potentially faulty cells
• Over the coming 4-5 weeks, we will be coordinating a phased replacement program of affectedbattery packs with new packs containing LG M50T cells

These incidents are rare, but obviously unsettling when they occur.

If you do wish to continue using your Nikola+ during the interim, the statistical risk of a spontaneous battery fire is present enough, so please store in an outside area, or alternatively discharge the Wheel & remove the battery packs, we will provide a prepaid return shipping label. 

 

There will be a follow-on communication when there is more information from Gotway, in the next week or two.

 

Edited May 31, 2020 by davinche
Clarification on "100%" charging

[davinche]

Backstory:

It was Sunday (memorial day long weekend). My friend has been EUC-curious for a while and wanted to learn, so we planned the learning/teaching session on Sunday. I had a V8 (which he was going to learn on) and I had my Nikola. A mutual friend of ours also tagged along because she wanted to document the learning process.

My friends arrived at my place at ~2:00pm. There is an empty parking lot nearby about 10minutes (walking distance) away. We turned on the wheels and walked to the parking lot. Once at the parking lot, I had my friend gear up. He had a helmet and i gave him my extra kneepads and wrist guards (I got two sets of ewheels wrist guards b/c of the 2 wheels i bought). I started teaching him the basics - how the device works, how to figure out the dominant foot, how to properly mount/dismount. Once he got used to all of that I got him going on some drills (push the EUC along with some supporting foot). While he was practicing, I decided to take my Nikola for a spin around the block. I wheel it away from the wall it is leaning against, and tried to mount it. As I mounted, the wheel then suddenly turns off and I almost fall. Our mutual friend laughs at me, saying something along the lines of "aren't you supposed to be good at this?". I was of course more concerned that the wheel suddenly turned off so I started examining it. Pushing on the power button did nothing so that was alarming. 20 or so seconds later, white smoke starts coming out. I tell everyone to back up (I've seen the video of the other Nikola "exploding"). I thought maybe a fuse or a mosfet blew somehow. I did not expect the whole thing to go up in flames.

Of course the fire department was involved to put out the fire. I had to give a statement about the make and model... This whole thing is bad... but I think the worst thing that came out of this is that my friend no longer wants to learn. I was unable to share the joy of riding an euc because of this incident.

My backpack that I had with me was also lost due to the fire. I had some water bottles in there, but also my V8 charger. I was planning on lending the V8 to my friend so he could practice on his own after our session. I mentioned this to Jason, and he just sent me a replacement one free of charge.

Overall, I guess the silver lining is that it all happened outside. Without knowing why the thing just went up in flames, it could've happened while it was inside my apartment. I'm also super grateful that I purchased my wheel through a distributor that puts the safety of his customers above everything else.

Edited May 30, 2020 by davinche

[redfoxdude]

Oh wow, that is wild, I'm sorry this happened to you. How scary! I am glad you are okay, and that this didn't happen inside. Jason is super awesome, that's for sure. Hopefully once this blows over, your friend may pickup interest again. This really is quite rare.

[davinche]

One last post:

Jason only shared the photos, but here is a link to all the stuff my friend was able to capture. Note: we were laughing in video... because we were in shock / hysterical about how something like this could've even happened. Lithium ion battery explosions man... they're no joke.

https://drive.google.com/drive/folders/16OmH-pp96OO1PcYyTYf2m-vYbLFyCFhW?usp=sharing

Edited May 30, 2020 by davinche
grammar

[.....]

Holy crap! Now I'm starting to eyeball mine that sit next to a bike full of gas. Thank goodness that wasnt indoors. The price of a wheel isnt jack squat compared to a house next to a hay field with volunteer fire dept. So glad you are okay. How long have these newer cells been in use now? Not yours, but altogether?

[davinche]

1 minute ago, ShanesPlanet said:

Holy crap! Now I'm starting to eyeball mine that sit next to a bike full of gas. Thank goodness that wasnt indoors. The price of a wheel isnt jack squat compared to a house next to a hay field with volunteer fire dept. So glad you are okay. How long have these newer cells been in use now? Not yours, but altogether?

I bought the wheel when they were first listed on ewheels. I only started using it in January (was away with family for the christmas holidays). Been using it for 4 or so months as my commuter. Stopped using it due to COVID. Sunday was the first time since the start of COVID that I wanted to ride it.

[fred8569]

Oh crap, I'm sorry for your loss. I'm following this case with attention. How many miles have you been riding it so far ?

[Chaindrop]

Question regarding Lithium-ion fires: In cases where a fire starts, can they explode even when the device is turned off? or does it usually just happen when you turn on the device when the batteries are faulty?

[davinche]

1 minute ago, fred8569 said:

Oh crap, I'm sorry for your loss. I'm following this case with attention. How many miles have you been riding it so far ?

Darknessbot says 495.3 miles. There are a couple of trips that aren't logged there, so about 500miles.

[davinche]

Also mysteriously... I've been obsessed in trying to figure out what even caused this to happen. But one of the things I did was to look on aliexpress for the Nikola 100v 1800WH. All of the sellers are selling them with LG M50T cells now.... makes you wonder why they deviated from the Panasonic cells 🤔

Edited May 30, 2020 by davinche
grammar

[alcatraz]

Are those cells the refurbished tesla motor cells? Maybe Jason could help answer that.

[Ben Kim]

the big clue is ewheels fast charger. those have been known to overcharge causing other fire issues (one in nyc) 

[fred8569]

4 minutes ago, Ben Kim said:

the big clue is ewheels fast charger. those have been known to overcharge causing other fire issues (one in nyc) 

It makes me ask you one more question @davinche : Were you using your wheel at 100% battery out at normal and lower state of battery ?

 

By the way, what kind of default a charger can possibly have if it charges at continuous amperage ?

 

Did we know more about this other case you just referred to ?

[Melody Ko]

Interesting, I received my Nikola Plus this may, ordered may 5th. I don't think my wheel is part of the recall, but I was  e-mailing Zen Lee and Jason about why the heck is my fan on all the time and making pulsing and then sounds like a rocket after riding for awhile. I did a little experiment just now and maybe this is the new behavior for the Nikola Plus wheels to be on all the time and then higher RPMs once it hits 100F. Maybe they changed the behavior of the wheel to have the fan on all the time to prevent overheating and prevent thermal runaway in the newer batches?

[davinche]

22 minutes ago, Ben Kim said:

the big clue is ewheels fast charger. those have been known to overcharge causing other fire issues (one in nyc) 

Ewheels asked me if I saw any of the overcharging symptoms in the charger (eg: display > 100v, etc). I did not. Also, the fire didn't happen whilst charging, it happened outside when I took the wheel out.

 

14 minutes ago, fred8569 said:

It makes me ask you one more question @davinche : Were you using your wheel at 100% battery out at normal and lower state of battery ?

 

By the way, what kind of default a charger can possibly have if it charges at continuous amperage ?

 

Did we know more about this other case you just referred to ?

I used the fast charger from ewheels. But I've never charged it to full. I've only used the 3A, 90% setting. The charger shuts off by itself once it reaches the desired voltage. I've never left a charger plugged in overnight though even though this charger has this safety feature. It has always reported 96-97V when the wheel is done charging.

Edited May 30, 2020 by davinche

[davinche]

31 minutes ago, alcatraz said:

Are those cells the refurbished tesla motor cells? Maybe Jason could help answer that.

I've also been doing some research on that The tesla cells were in fact jointly created with Panasonic and I believe the 21700A are supposed to be them. Whether or not the ones in my wheel were refurbished... 🤷‍♂️

[alcatraz]

They have three small lines (tesla stamp) on the negative side.

[WI_Hedgehog]

Note of caution: Charging to 90% doesn't engage the balancing circuitry in the top-balancing boards I've seen. I understand Gotway uses top-balancing boards.

In theory, this could allow a cell to get out of balance and drop below critical voltage. At such a depressed state a cell can undergo a chemical change and permanently die, or overheat during use. The death of one cell affects those in parallel with it, amplifying the problem and increasing the risk. 

---

Also of note is cell design. In highly simplified terms, the more lithium there is in the anode the more powerful the cell. However, when charging, lithium ions reaching the anode and don’t form a smooth layer, but instead form spikes called dendrites, which can grow large enough to pierce the insulator and create a short circuit between anode and cathode, possibly resulting in a fire, not necessarily during charging, as heat (thermal expansion) / vibration could cause the dendrites to piece the insulator. 

---

Oddly, the two can work together. Dendrites don't easily break up, which lessons the cell's charge capacity, causing the rest of the cell to work harder and heat up during discharge and thermally expand. With a lowered charge capacity the cell also charges up faster, possibly forming more dendrites.

Also of note is battery life can  generally be doubled by not charging above 80% capacity, or not running the battery below 30%. So if you have to pick one or the other, it's better to charge the battery fully than it is to discharge the battery fully. An added benefit is charging the battery fully engages the balance circuits, and also doesn't cause a decrease in speed due to lowered battery voltage while riding like would more easily happen when charging to only 80%.

[Gadgetfann]

There was mention of the Nikola’s battery pack appearing “swollen” in this post by ecodrift back in December.   Photos - Ecodrift disassembles the Nikola 100V 21700

Edited May 30, 2020 by Gadgetfann

[.....]

Makes me wonder if having ALWAYS charged to 90%, did the balancing circuit EVER get to engage and get the cells even? Just a shot in the dark, Im no chemist. I also find it odd that most sold on ali are now the m50T type. Makes you also kind of wonder about the OTHER wheels coming out with these NEW and BETTER cells... This aint going to help gotway any, thats for sure.

Edited May 30, 2020 by ShanesPlanet

[davinche]

12 minutes ago, WI_Hedgehog said:

Note of caution: Charging to 90% doesn't engage the balancing circuitry in the top-balancing boards I've seen. I understand Gotway uses top-balancing boards.

In theory, this could allow a cell to get out of balance and drop below critical voltage. At such a depressed state a cell can undergo a chemical change and permanently die, or overheat during use. The death of one cell affects those in parallel with it, amplifying the problem and increasing the risk. 

---

Also of note is cell design. In highly simplified terms, the more lithium there is in the anode the more powerful the cell. However, when charging, lithium ions reaching the anode and don’t form a smooth layer, but instead form spikes called dendrites, which can grow large enough to pierce the insulator and create a short circuit between anode and cathode, possibly resulting in a fire, not necessarily during charging, as heat (thermal expansion) / vibration could cause the dendrites to piece the insulator. 

---

Oddly, the two can work together. Dendrites don't easily break up, which lessons the cell's charge capacity, causing the rest of the cell to work harder and heat up during discharge and thermally expand. With a lowered charge capacity the cell also charges up faster, possibly forming more dendrites.

Also of note is battery life can  generally be doubled by not charging above 80% capacity, or not running the battery below 30%. So if you have to pick one or the other, it's better to charge the battery fully than it is to discharge the battery fully. An added benefit is charging the battery fully engages the balance circuits, and also doesn't cause a decrease in speed due to lowered battery voltage while riding like would more easily happen when charging to only 80%.

Hmm... so what is the correct way to charge then? Also, is it only gotway boards that do "top-balancing"? What about Kingsong or Inmotion bms?

[.....]

6 minutes ago, davinche said:

Hmm... so what is the correct way to charge then? Also, is it only gotway boards that do "top-balancing"? What about Kingsong or Inmotion bms?

Now THAT is a can of worms and topic all its own. Theres a recent thread around here about it. I charge mine fully and allow to balance for a while after full. I also try to long term store them at 80% or so. Slower charging and not allowing to drop extremely low, very often. Letting them cool after riding before charge and cool after charging before ride, is also in my routine. I think youll find that your seemingly simple question, is a rabbit hole of information to chase down.

 

Edited May 30, 2020 by ShanesPlanet

[davinche]

1 hour ago, Gadgetfann said:

There was mention of the Nikola’s battery pack appearing “swollen” in this post by ecodrift back in December.   Photos - Ecodrift disassembles the Nikola 100V 21700

The last bit of the (translated) post says: "Gotway encountered some difficulties when using Panasonic elements, so LG is now used." What is this "difficulty" that Gotway encountered?

[alcatraz]

Truth is we don't know if our balancing boards work the way the should or not. One of my Inmotion V8 doesn't balance, and there's no way to tell. If I had ridden it normally I would maybe have had a fire.

If you have a sudden drop in range, or can't charge to 100%. These are warning signs.

The fires, I think, come after repeatedly crossing over the threshold or trying to revive dead cells by fully charging a pack with dead cells in it.

[Chriull]

1 hour ago, alcatraz said:

The fires, I think, come after repeatedly crossing over the threshold or trying to revive dead cells by fully charging a pack with dead cells in it.

+1!

Dead cells can also while beeing burdened during riding be forced to change polarity - as they do not supply current anymore, they are charged by the others the wrong way around.

Another way to catch fire is just thermal runaway by beeing overburdened (shorted)

6 hours ago, davinche said:

I wheel it away from the wall it is leaning against, and tried to mount it. As I mounted, the wheel then suddenly turns off and I almost fall.

....

I was of course more concerned that the wheel suddenly turned off so I started examining it. Pushing on the power button did nothing so that was alarming. 20 or so seconds later, white smoke starts coming out.

My first thought from this description would have been that the mosfets fryed/motor wires shorted and overloaded the batteries so they started to burn after 20 secs?!

Afaik GW BMS have _no_ overcurrent/short circuit protection! So if anything happens (QC issues!) they can blow up! Don't know if this was changed with recent models?

@davinche - were there still enough remains so they could do some forensics?

Gives a really bad feeling to hear from such incitents - great nothing happened to you!

It's time that all manufacturers use smart BMS with single cell (group) monitoring and cell temperature monitoring! (...without draining the batteries... )

... and that GW uses short circuit protection again, if they not already do...