Oops - Left my mech discharging

[cheesestain]

So, I did something dumb which was leaving my mech unlocked in the car and it was discharging for about 20 minutes.

I had a full battery and a 1 ohm coil. When I got back it was pretty hot but not scalding. Was able to hold it and take the battery out. I let it cool and the battery looks ok. The plastic isn't damaged. Got home and measured the voltage and it's reading 3.95v.

Is the battery safe to use?

 

[Baditude]

I doubt that the battery was discharging continuously for a full 20 minutes, and still be reading 3.95 volts. Something doesn't sound right to me.

I've had an ICR battery explode in a mech under similar circumstances. I have no idea how long the battery had been discharging after the fire button had become pressed against another mod in a pants pocket in my locker, but when I found the mod it was too hot to touch. I managed to remove the mod and then the battery. Both ends of the battery had vented apart and the cell housing had collapsed. Apparently the battery had vented flames as the pants pocket was burnt.



You never said what kind of battery you were using, but I'm assuming it was an IMR safe-chemistry battery. You were lucky. IMR batteries only vent gas, but are unlikely to explode dramatically like an ICR battery.

I've also had an IMR battery vent when it came into contact with some coins in a pocket. It got extremely hot and I could hear the gas being released. I saw no signs of battery damage but I know it did vent from the sounds it made (high pitched whine).

Personally, I would not use that battery again despite the normal voltage reading (which I still don't understand). It's not worth the risk. High temperature causes internal damage to the battery whether you see external damage or not.

 

[cheesestain]

I'm basing the 20 minutes on approximately how long I was in the store for.

Sorry forgot the battery type. It's an efest purple 18650 35A 2500mah

 

[Baditude]

I'm basing the 20 minutes on approximately how long I was in the store for.

Sorry forgot the battery type. It's an efest purple 18650 35A 2500mah

A for-your-information tip: That battery is actually a re-branded LG18650HE2 battery. The manufacturer of that battery, LG states it is only a 20 amp continuous discharge rating, not 35 amps. Efest is misrepresenting the continuous discharge rate (20 amps) with the pulse rating (35 amps). Efest has a history of over-rating the mAh and amp ratings of their batteries.

Efest 30 & 35 amp batteries

 

[Ryedan]

I'm basing the 20 minutes on approximately how long I was in the store for.

Sorry forgot the battery type. It's an efest purple 18650 35A 2500mah

Those are hybrid IMR rebranded LG batteries like Baditude said. They start at 4.2V off the charger and it's OK to run them down to around 3.3V regularly (though in a mech mod I try not to go below 3.6-3.7V) so 3.95V is no problem at all. It probably wasn't on for the whole 20 minutes or I think the voltage would be lower.

Lesson learned. Vape on

 

[Rickajho]

Are you sure it was actually discharging? It was in a car and things got really hot, but it still metered 3.95 volts... How hot was it that day?

Leaving Lithium batteries in a closed up car when cabin temperatures can easily climb over 100 degrees F is a really bad thing to do. Leaving them inside a heat conducting metal tube of a PV only makes the scenario worse.

 

[cheesestain]

It was definitely discharging because I didn't lock it and it was noticeably hot. It was in the evening and dark so the car wasn't that hot. Also the cotton in my dripper was bone dry. Strange that the cotton wasn't burned. So maybe it wasn't discharging the whole time.

Lesson learned. Hopefully I won't make that mistake again. I think Baditude is right. I should just pitch the batteries and I'll get some VTC 5's.

 

[Froth]

It was definitely discharging because I didn't lock it and it was noticeably hot. It was in the evening and dark so the car wasn't that hot. Also the cotton in my dripper was bone dry. Strange that the cotton wasn't burned. So maybe it wasn't discharging the whole time.

Lesson learned. Hopefully I won't make that mistake again. I think Baditude is right. I should just pitch the batteries and I'll get some VTC 5's.

I wouldn't just throw out a working LG18650HE2, even if it got a little warm/hot it's still quite a good battery and with a 1 ohm coil you will notice zero real difference with a VTC5. Just my personal experiences, I own both batteries and above say .4-.5 ohm their performance is almost identical. So long as the battery you had issues with charges up fine I would personally continue using it, I have used batteries after much worse happening with zero issue.

 

[dwcraig1]

Guess I'll post my mishap, an hour ago I was smelling my juice while surfing FT. So I grabed my Taifun GT and Taifun mod hanging around my neck and checked to see if it was leaking ,it was not leaking. After a while I saw juice all over my desk around my other mod (with the same flavor juice), it was so hot from top to bottom that I had to use paper towel to remove the battery. In the end there was no actual damage.
I thought at first that the button stuck on my Stingray but closer inspection revealed a bare spot near the top of the heat shrink wrap on the battery. Well back to FT and ordered a couple of meters of 29 mm heat shrink tubing. Pretty scary situation it was.

 

[Froth]

Well back to FT and ordered a couple of meters of 29 mm heat shrink tubing. Pretty scary situation it was.

That tubing works good, I've got black green and clear sitting beside me.

 

[TamiPac]

That tubing works good, I've got black green and clear sitting beside me.

Where did you get your tubing Froth? I need colored tubing for my 26650's and am having a really hard time finding any good colors.

 

[Froth]

Where did you get your tubing Froth? I need colored tubing for my 26650's and am having a really hard time finding any good colors.

Not sure if they supply it in the correct size for 26650 batteries, but this is where I purchased the shrink for my 18650 size batteries.

https://www.fasttech.com/p/1334308

 

[TamiPac]

Not sure if they supply it in the correct size for 26650 batteries, but this is where I purchased the shrink for my 18650 size batteries.

https://www.fasttech.com/p/1334308

No, unfortunately they only go up to 18650 size and I am having fits and have sent out many e-mails to find the larger stuff. Wish me luck in my quest and thank you for answering!