Just seen this
Hereâs a pic of the inside that was posted on reddit. Not sure what you can actually tell, but if it didnât originate from the stormcore the SC sure did take a hit. Iâd probably guess it was the BMS, but really canât tell. Those front cells do look pretty rough however he put it out with a standard fire extinguisher so I wasnât a lithium fire, yet. Random note, he did use super cheap motors for some other pretty premium parts on the build.
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I believe it was the CF of the deck that shorted out the uninsulated cells when he stood on the board for the first time. He put P42As in the enclosure designed for 18560s so it was already tight.
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Full pack short does add up based on the shrink wrap being burned all the was along the side opposite the fire. I guess I should quote his text for context. Being that it wasnât even during operation, I think you can rule out the possibility of the stormcore or BMS being the culprit.
After finally (basically) finishing my DIY âBatmobileâ that I have spent 5 months on as a busy engineering student, I screwed the enclosure lid down and stood on it for the first time with wheels. It was wonderful⌠until I heard a hissing sound and smoke started billowing out of the deck. Ran the board outside to the parking lot where I proceeded to unscrew the lid to try and put the fire out before it blew up the entire battery.
Never got to ride it which is the worst part. Weâll see if I pick the project back up later.
Just thought the good people of this subreddit would be entertained by another horror story. Not intended to put anyone off from building a DIY just a reminder to always be extra careful and not do anything above your very comfortable skill level.
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Whose board was this?
Wow that is scary, the epicenter does look to be this group of cells
He was fast enough to extinguish it, so the root cause can be identified
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From this reddit post:
https://www.reddit.com/r/ElectricSkateboarding/comments/l7xgnq/rip_my_diy/
My guess based on this:
Tried the plastic cell dividers and welded the cells before realizing the extra 1mm per cell made the pack too big for the enclosure. Had to strip all of the welds and go about using the cells without dividers. Also the old ESC was a FESC 6.6 that 1/2 of stopped working when I was about to start testing.
Also:
I lined the entirety of the battery enclosure in adhesive fish paper. Now there was a section of the board where the 3 cells that did explode that wasnât lined because they stuck about 1 cm out of the âbattery enclosureâ part of the deck.
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hot damn, remembered what i asked u two days ago?? @BenjaminF 
guess i was too stupid to think it would work
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Itâs the Ownboard/Boundmotor/Esk8Supply carbon fiber integrated deck. I am highly skeptical of that deck having enough vertical space for a 21700 battery.
That particular deck bumps up in the rear of the enclosure cavity to have a shallower section for the ESC, for some reason. The redditor actually made his pack too long, so the cells from his last group were resting on that bump. He also said he attempted to sand that bump down to get the cells to fit.
My theory is that when he sanded the CF down, he basically made a big patch of rough, raw CF, then when he stood on the lid it pitched his pack in that spot causing the cells to short out through the CF.
The takeaway here is that if you are going to use that deck, dont use 21700s, and if you are going to use 21700s, DONT TRY TO EXCEED THE BATTERY SECTION OF THE ENCLOSURE COMPARTMENT.
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18650 barely fit in the evolve carbon which those decks seem to be based off of no?
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âbarelyâ is an understatement.
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Yo wtf is going on with those welds
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welds are way too hot, and there are too few of themâŚand omg so many other thingsâŚthis person should not be building batterires
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By the looks of it he, while putting the lid on, squeezed 2 balance wires together or cut one of the wires on sharp edge, would explain the calm fire he had, if pack was full shorted it wouldâve gone with a huge bang quite rapidly.
Also if you have to squeeze the lid on to compensate 1mm youâre doing something wrong to begin with. Maybe itâs good thing it blew up now instead of during the ride or while charging at home.
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Yeah wouldâve been worse if it did that while he was sleeping or something. Esk8 is growing, so Iâm guessing weâll be seeing more of this unfortunately. People messing with dangerous things they donât understand.
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At this pace, soon enough, we will get regulations for battery carrying and purchasing. Which may be a good thing.
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Bump. I am also wondering this.
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freakin unscrewing it while on fire. was brave. 
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