Jump to content
davinche

[WARNING] Gotway Nikola 100v 1800WH Battery Fire

Recommended Posts

Mind if I interrupt the conjecture for a minute to ask if anyone is having trouble fitting their replacement cells inside of their shell? 

I was able to jam the new packs inside my shell and screw it down but it is bending a fair bit. I did not get a chance to compare the widths of the packs before replacing them. 

Share this post


Link to post
Share on other sites

That coating looks good. Is it hard to do? Is it expensive? Is it impossible to take off? Do you get a lower board temperature reading after adding it?

I like the idea of added moisture protection and temperature dissipation.

@Aibolit66:thumbup:

Share this post


Link to post
Share on other sites
Posted (edited)

Another possible reason for the runaway heat are the nickel strips. I've seen gotway packs use waayyyyyy too low crossectional area nickel strips. At the ends of the packs you have something like 4 negative poles connecting to 4 positive poles with a single nickel strip. At the center the peak currents are heating up the strip extremely hot. The shrinkwrap starts to melt. Both the outer wrap and possibly also the cells wrap.

Because the tesla motor cells have been refurbished and rewrapped, maybe some refurbers used low melting point shrinkwrap so that common gotway pack temperatures actually melted it and caused outer casing short circuits.

If replacement packs are slightly larger, that could indicate added cell casing protection between groups. It means that's likely what caused the fires.

Edited by alcatraz

Share this post


Link to post
Share on other sites
19 hours ago, D3m0nzz said:

Mind if I interrupt the conjecture for a minute to ask if anyone is having trouble fitting their replacement cells inside of their shell? 

I was able to jam the new packs inside my shell and screw it down but it is bending a fair bit. I did not get a chance to compare the widths of the packs before replacing them. 

There's some commentary on facebook... one guy had to shave down some of the foam padding to fit the new batteries.

Share this post


Link to post
Share on other sites

MOSFETs on controllers sometimes burn on all EUC manufacturers.  This happens outwardly, with the burnout of the legs of the transistor, with the burnout of the tracks on the controller board.  I think the reason is the overheating and shorting of the MOSFET of this phase.  In our cases, such a severe damage to the controller was observed in the EUC Gotway with a homemade increased battery during slow uphill movement.  We must acknowledge the poor design of the thermal interface of the controllers.  Now I am making a controller with AlN thermal padding and thermal compound, then there will be a test.  This is for the custom EUC model.  One controller with a normal thermal interface has already burned out.  If something is not clear, I apologize for the translation.

Share this post


Link to post
Share on other sites
Posted (edited)

Это выглядело так.

76004E5F-8C45-4957-9E3E-8A25DA80581E.jpeg

323D10A2-3277-4589-A731-3CEEED6EE5E0.jpeg

Edited by Aibolit66

Share this post


Link to post
Share on other sites

Hopefully you will get some service from the seller.  I was thinking about ordering a MCM5 or Tesla from this same seller.  I will not order until I see you get service.  Keep the thread updated so others can hold off ordering also.

Share this post


Link to post
Share on other sites
On 7/19/2020 at 12:01 AM, Tobbe84 said:

 

The Monster is now with a friend that works with batteries and he is going to cut open the battery pack and see if he can fix it. Also find out what caused this and what cells it really is. I think he's going to film it. Hope it's an easy fix. Too bad I can't ride the Monster now when I'm on vacation :( Only answer I've got from Wheel Riders Store is that they are working on it whatever that means. 

Share this post


Link to post
Share on other sites

Terrible customer service so far.  They claim to have good after sales customer service.  To bad more potential buyers will not see this thread.  I wait to see how this plays out.  I will not order from them unless they prove their claim of good after sales service. These are expensive products.  Its not like a busted flashlight that you can just throw away and buy a new one.

Share this post


Link to post
Share on other sites

I find it somewhat of a co-incidence that the pictures of the Nikola, Tesla and Monster boards all have the primary heat damage in exactly the same place, along with the now recent Sherman board. Theres clearly a localised heat management issue in the area of one of the big capacitors. Whether it's the cap to fail first I don't know, as why just the one and not both? Maybe current is not fed equally between both? Or maybe it's another component that just happens to be nearer one of the caps than the other (FET maybe?). Either way, given how uncannily similar all the fried boards look, theres clearly an area to point fingers at.

Share this post


Link to post
Share on other sites
34 minutes ago, Planemo said:

I find it somewhat of a co-incidence that the pictures of the Nikola, Tesla and Monster boards all have the primary heat damage in exactly the same place, along with the now recent Sherman board. Theres clearly a localised heat management issue in the area of one of the big capacitors. Whether it's the cap to fail first I don't know, as why just the one and not both? Maybe current is not fed equally between both? Or maybe it's another component that just happens to be nearer one of the caps than the other (FET maybe?). Either way, given how uncannily similar all the fried boards look, theres clearly an area to point fingers at.

Seems the common thing is the burned pcb between battery wires and the mosfets. Capacitors seem to happen to be just above the mosfets/pcb tracks.

Before motor wires were screwed to the sockets on the PCB they tended to desolder themselves und burden.

So maybe the same thing happens now with the battery wires? One "free floating" wire could shorten with the not insulated capacitor legs.

I assume (hope) GW is working on a new board design - then we'll see what they changed and how this works out...

Share this post


Link to post
Share on other sites

Agreed, maybe it's a case of one of the battery wires de-soldering from the board due to heat and from there on the real havoc starts...

Share this post


Link to post
Share on other sites
8 hours ago, Planemo said:

I find it somewhat of a co-incidence that the pictures of the Nikola, Tesla and Monster boards all have the primary heat damage in exactly the same place, along with the now recent Sherman board. Theres clearly a localised heat management issue in the area of one of the big capacitors. Whether it's the cap to fail first I don't know, as why just the one and not both? Maybe current is not fed equally between both? Or maybe it's another component that just happens to be nearer one of the caps than the other (FET maybe?). Either way, given how uncannily similar all the fried boards look, theres clearly an area to point fingers at.

See, I don't mean to be a Gotway hater, but that's also what I'm curious about. So far a lot of observed failures seems to be coming from Gotways. One can of course blame it on mods, but at the same time I'm just wondering whether to put all the blame on the mods, or if the mods are just a demonstrator of weaknesses / lack of protection in GW designs.

Share this post


Link to post
Share on other sites
44 minutes ago, davinche said:

So far a lot of observed failures seems to be coming from Gotways.

Yes. They seem to be quite on top of failure rate published by the big resellers.

45 minutes ago, davinche said:

or if the mods are just a demonstrator of weaknesses / lack of protection in GW designs.

GW are imho already quite on the edge. Power, speed and so burdenwise. And they have no/the least limitations and protections.

The battery size is a "natural limitation" of how much power can be supplied - putting a bigger(stronger) battery inside easily overburdens the system...

... beside some mods shown here seem to overburden themselves... :(

Share this post


Link to post
Share on other sites

I remember when the one of the aliexpress sellers was warning his customers to avoid the first batch of 21700s as these were all unofficial versions made out of used electric car batteries. People were fuming and accusing him of lying to clear old stock.. Guess he showed'em haha. 

Share this post


Link to post
Share on other sites
48 minutes ago, Tinkererboi said:

I remember when the one of the aliexpress sellers was warning his customers to avoid the first batch of 21700s as these were all unofficial versions made out of used electric car batteries. People were fuming and accusing him of lying to clear old stock.. Guess he showed'em haha. 

Is there any proof of this? From the video it looks like the issue might have been bad spot welding.

Share this post


Link to post
Share on other sites
21 hours ago, Tobbe84 said:

https://www.youtube.com/watch?v=uOsT7ITUpLg

We determined that the rust came from battery fluid that had leaked out from the exploded cell and destroyed the other 6 cells.

Thanks for the detailed video!

Summary of observations:

  • The balancing leads across one cell group measured 0V.
  • It's a 7p pack. In this cell group there were three 0V cells, and four normal-voltage cells.
  • Other parts of the pack showed weak welds on the cell straps.
  • Mild corrosion was observed on the cell straps near the bad group, but no conductors were rotted or visually open.

The clear part for me is: 4 cells of a group were open-circuit, and the remaining 3 cells were then overdischarged (damaged) during use.

It makes me wonder what happened first...

A )  Open-circuit welds were caused by weld defects and normal vibration. Corrosion was caused later, by heat and vapors released by the damaged cells.
or
B )  Corrosion was initiated from a cell that had a physical defect when the wheel was new. This corrosion resulted in open-circuits and subsequent overdischarge of remaining cells.
or
C )  Corrosion was initiated from water intrusion. Note that this pack was in the topmost position in the wheel (near a panel seam), but had an intact shrink cover, and cells near the ends of the pack (near the open ends of the shrink) did not appear corroded.
 

So- blame the welds? Or blame a cell?

(In any case, I'd be probing every single cell in that EUC, presuming that other weld joints may be open...)

Share this post


Link to post
Share on other sites

Is the issue still happening with the Nikola+? How to confirm a Nikola+ 21700 1800wh isnt from this problematic batch?

Share this post


Link to post
Share on other sites
On 8/1/2020 at 12:19 PM, Ronin Ryder said:

Is the issue still happening with the Nikola+? How to confirm a Nikola+ 21700 1800wh isnt from this problematic batch?

If you open your Nikola the battery states what it is. 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...