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Did I ruin my 18650


#1

Made a pack of (48) Lg hg2 and of course I had to have at least one big fuck up and it happened when I taped the pack together and one cell that had a bad wrapper shorted to a 4p set. It got too hot to touch and dropped .2 volts and the steel can even puffed a bit. Puffy 18650!
I didn’t have an extra to replace it with so threw it in. What’s my forecast?
How can u even know what’s going on with paralleled cells?


#2

Back to lipos for you


#3

I’m on 9s lipo down from 12s…in one month! Puffy galore. Actually these new duds aren’t puffy but have no voltage at all. At least they’re safe. Im slowly learning that lipos stuck to the bottom of the board is no good. Had to be proven


#4

Dude u need to suck it up and ride with an enclosure or embed them in the board


#5

O just u wait and see. It’s coming


#6

Look forward to it


#7

Don’t burn your house down @hummie! I wouldn’t use a puffy 18650 and would just dispose of it. Can you check the voltage of the cell?


#8

Yea it dropped .2. They’re the safest li-ion chemistry at least. I’m running it. I’m moving up. Better than my lipos. I just need one person to tell me it’s a good idea


#9

Dropped .2v? or dropped to .2v?


#10

Too hot to touch and the can puffing…
I think the answer is clear.

Discharging the cell that quickly (through the short) will definitely lessen its lifespan and performance.

Theres’s also the risk of thermal runaway…

Edit: (I am NOT recommending this) I wonder how it would fare if connected to the pack with its own cell-level fusing (the type used in Tesla Li-ion packs)


#11

. Just down to 3.4 from 3.6


#12

Ok I’ll maybe switch it out


#13

If you are chucking it out, make sure to follow youtube instructions to dispose of correctly.


#14

If I hook it up to my wall outlet and blow it up then I won’t have to think about disposal

I’ve read dropping in salt water works…then tried it and it doesn’t. It just oxidized the tabs and all the energy was in there still. Maybe a large resistor next time. Maybe a banana. Gotta give it its last hurrah


#15

a small light bulb should work

it’ll discharge the cell slowly


#16

A word of advice, fuck lipo bags, just put them in a clay pot and save your self time and money


#17

Wait, what? I have a build on hold for someone and he didn’t want to pay for an enclosure. I told him it was a bad idea… Could I just add a thin plastic shell to them?


#18

The reason exposed lipos are bad is because either a point rock can kick up and puncture it giving your board a sweet nitro boost complete with lithium flame, or you run over a bump that’s a bit too high and crush the lipo. Plastic shell would be better than nothing.


#19

I’ve ruined many lipos on the bottom of the board in many ways. If u insist on doing it using good Velcro or glued with liquid 90duro polyurethane (what I did) then also get some hard polyurethane from smooth-on (task 9 or onyx maybe) and put a layer of carbon or fiberglass on. Make sure they’re not too heavy for the Velcro or you’ll be done quick. I never had flames or smoke. Just died puffy or not. They are fragile. I now can say it. I have a lipo bag of duds


#20

Yeah I get that (been in RC a while) but saw enough pictures here I figured it would be ok. I’ll just turn them into hard case lipos.