Liitokala 26650 kicked the bucket

Batteries and Chargers Rechargeable Batteries
1

One of my 26650’s died on me yesterday. It’s one of these blue Liitokalas that I purchased a couple of years ago, maybe 3 or 4 years ago, can’t remember, but it was when they just came out.

I was using it in a zoomie, one of those cheap chinese lights that I modified with a 3A driver, a solid pill and a XM-L2 U2 on a noctigon star. The thing gets really hot after a while. I measured over 110ºC pointing an infrared thermometer at the emitter. The case gets almost too hot to the touch after a few minutes, so I’m guessing the battery gets pretty hot too.

After about half an hour of putting the Liitokala battery in, it made a popping sound and quit. I initially thought it would be the driver that failed, or perhaps the emitter, but nope, the battery is cactus: it measured only 1.5V and kept going down in voltage when I measured it. Also the flashlight still works fine after the incident.

So I thought, hey, let’s do something stupid and put it in the charger, see what happens. I prepared a little “bunker” just in case the hole thing burst in flames and plugged the charger to the wall. Nothing happened. The charger wasn’t even detecting the battery. I measured it again and it was at 3.5V but the voltage quickly bled out down to a few hundred milivolts. Apparently the charger puts 5V accross the batteries when none is detected. WTF :confounded:

I reckon the battery still had more than half of it’s expected cicles in it, measured about 4200mAh at 500mA discharge tests, down from some 5000mAh.

I’m just curious to know what may have happened to it. It looks intact externally, there’s no protection PCB on it, was this due to overheating? Was it a fail-safe kind of failure?

2

Does the flashlight work with another battery?

If the flashlight ‘shorted’ somehow it would destroy the battery.

Was the battery hot when you pulled it out?

3

The flashlight works fine with another battery, I don’t think it was a short because the battery wasn’t super hot, although I didn’t pull it out immediately to be honest

4

Protection circuit? Those can have nonresettable fuses (thermal or otherwise).

Also, if the cell itself cooked, it can melt something inside as if shorted out (to protect the outside world).

5

Internal thermal protection. Probably the same way HKJ blew his Shockli 5500mAh trying to test 30A continuous.

6

Bah… you beat me to it. I was just now trying to look up which cell he was testing that did that. :laughing:

7

Thanks guys, thermal protection makes sense to me, even though it was only drawing 3A, I guess being inside a flashlight didn’t help with cooling at all.
Apparently HKJ’s Shocklis blew at 86ºC, damn, that doesn’t seem such a high temp

8

its a safety feature preventing worse things
unfortunately it kills the battery permanently

9

Good to know. If it wasn’t for the great folks in these boards I might have been using cheap cells with no such protection… who knows what would’ve happened!
What do you guys recommend for 26650’s these days please? I just noticed the Littokala fraud at aliexpress thread. Damn. I’ll make sure to steer clear of those

10

These:
https://www.aliexpress.com/item/Shockli-26650-battery-26650-5500mAh-3-7V-li-ion-rechargeable-battery-20A-30A-for-high-power/32879818089.html

They’re more like 5700-5800mAh, which is very nice.

11

:laughing:

12

Thanks, those look great. I’m guessing the higher current rating suggests that they might run cooler than lower rated ones perhaps?
What puzzles me is that according to HKJ’s review of the cyan 26650 Liitokala, it copes with up to 20A, yet I managed to trip it’s fuse at only 3A

LMFAO!

13

@dazz

1. They have lower internal resistance, so yes.
2. Heat at any current can kill a cell.
The LED must have gotten the 26650 so hot that its CID activated.

14

Understood, thanks again BlueSword.
I’m a bit concerned now that my other 26650 is a black Soshine 5500mAh and it might not be as safe as the Liitokala. I wonder if I should throw it away just in case. It got a good review from HKJ, but maybe the protections in it are subpar or something

https://lygte-info.dk/review/batteries2012/Soshine%2026650%205500mAh%20(Black)%20UK.html

15

86*C = 186*F. That would burn you in seconds if touched. You seriously don’t think that is too hot.
Li-on start to deteriorate at 140*F.

16

What a coincidence… One of my INR26650-50A (it looks very similar to the Liitokala blue 5000mAh 26650, but is not labeled Liitokala; I would presume the are similar; I bought them from an AliExpress store when they were still able to ship batteries to my country nearly 2 years ago).

I haven’t used my blue 26650 that much (mostly when I test 26650 flashlights), but I had been charging 4pcs 26650s on my Miboxer C4-12 (3pcs were the cyan INR26650-50A and 1pc of another brand). Our ambient temperature is very hot nowadays, I had just placed them on the Miboxer C4-12 charger, but when I came back to check later, I notice that one slot (the cyan 26650 that became bad) does not detect a battery anymore. I removed the battery and it measured less than 1.0v.

I also noticed the other batteries are reporting 50+ degrees Celsius (on the Miboxer C4-12 display). The charger automatically selected the fastest charge speed (3 amps) for the 4 batteries when I first inserted them.

I wonder if high temperature killed my cyan 26650? The other 2 cyan 26650 and the other brand 26650 on the C4-12 charged to completion sucessfully.

17

I see what you mean. HKJ stopped the tests of these cyan Liitokalas at some 50ºC because he deemed that too hot, so yeah.

You mean 140ºC, right?

18

Interesting. Looks like maybe these cells have a tendency to overheat

19

If your light has killed a perfectly good 26650, maybe it's not batteries you should throw away or replace ;)

20

What would be a good design to prevent these things? Do I need a driver with a temperature sensor perhaps?

I have a couple other lights with LD-2 drivers, but I’m not using the temp sensor on those :confounded:

This light is fitted with a 3A 8x nanjg 150C