Help needed to fix some Thrunite 18650s that I screwed up

Hi everyone!
I have 2 Thrunite 18650 batteries that are dead or sleepy and I want to revive.
One of the cells shows a broken or open (I don't know the exact term in english) circuit, so after doing some research online, I have determined that it is a CID issue. I have watched a few videos about the matter, and all of them revive the cell by pushing the CID though some holes that the terminal has. Example: https://www.youtube.com/watch?v=1w3Tv1Jg0ps
The problem is that the Thrunite 18650 has no holes in its positive end. So the only way that i think is suitable, would be to drill a small hole in the center of the + lead, and then push though it onto the CID with a small screwdriver or something similar. What do you think about this?
The other battery seems a little more complicated, because the circuit is closed (so no CID issue there) but the voltage is 0.0V. I have seen this other videos regarding similar issues: https://www.youtube.com/watch?v=tbEfhPbqTDE and https://www.youtube.com/watch?v=Vh0OKa5TSX8 I have tried to replicate these techniques by trying to charge the cell with my Sky Rc charger as if it was a NiMH cell. I put it charging at 0.1A and the voltage beggins to go up. However, after a few minutes doing so, when the voltage gets over 2 volts, the current stops and the cell goes back to 0.0V. I have tried the same charging at 0.5A and its voltage went as far as 3.4V, but again, the current stopped, and the voltage dropped again to 0
Any idea on what else can I try?
Thanks to everyone in advance
Pablo

PabloVS said:

..............The other battery seems a little more complicated, because the circuit is closed (so no CID issue there) but the voltage is 0.0V. I have seen this other videos regarding similar issues: https://www.youtube.com/watch?v=tbEfhPbqTDE and https://www.youtube.com/watch?v=Vh0OKa5TSX8 I have tried to replicate these techniques by trying to charge the cell with my Sky Rc charger as if it was a NiMH cell. I put it charging at 0.1A and the voltage beggins to go up. However, after a few minutes doing so, when the voltage gets over 2 volts, the current stops and the cell goes back to 0.0V. I have tried the same charging at 0.5A and its voltage went as far as 3.4V, but again, the current stopped, and the voltage dropped again to 0
Any idea on what else can I try?
Thanks to everyone in advance
Pablo

Click to expand...

I'm not familiar with the problem on the 1st cell, but the 2nd cell sound like a tripped protection circuit.

If the problem was a tripped protection circuit (ie: will read 0.0v). Those are easy to reset by putting another cell in parallel with the tripped cell for 15 seconds or using a power supply set to something like 3.0v. A lot of the chargers don't know what to do when the voltage reads low or at 0.0v. So you have to manually reset it. By putting another cell in parallel, what happens is that you are forward biasing the body diode of the mosfet in the protection circuit which allows current to get to the battery side even though the mosfet is off. The voltage at the battery is likely around or under 2.50v (typical trip point). You can't read that voltage because the mosfet switch is off. So it doesn't take a lot of current to boost the battery up a little. Once voltage is above the trip point and stays there, the protection circuit sensing will no longer keep the battery in protection mode, you'll read above 2.50v and chargers will now be able to charge.

Now I'm not sure why you would use your Sky Rc charger in NiMH mode because you need a voltage at least several tenths above 2.50v just to be able to force current into the lithium ion battery.............. but when you tried at the 0.5A level and its voltage went up to 3.4v........if you were to remove the battery at that point, I would think the voltage would not trip off. But if the voltage went to 0v, it sounds like something is wrong with the protection circuit. Just a guess :shrug:. Next step would be to try a different charger or even a power supply that you set at 4.20v, and 0.5 or 1.0 amp current limit and see if it takes charge with the voltage gradually rising. That means the battery works. But if it goes to 0.0v thereafter, the protection circuit is bad. Maybe you just take the protection circuit off and rewrap and use as a non-protected battery. I've had to do that to a couple of my batteries.
http://www.candlepowerforums.com/vb...0mAh-18650-batteries-too-wide-now-retrofitted

Then again lithium ion needs to be handled with care. If the battery is bad, you probably just want to recycle it and get some knew ones with lessons learned!

So exactly what happened to get these batteries in their condition?

Let me see if I understand things?

One cell you've determined, has a faulty CID protection safety and you want to drill holes through the top of the cell and then cram something down into it, possibly resetting X, Y or Z?

The other cell appears to have a tripped PCB and reads 0.0v, but instead of getting a known charged/good cell and going nose to nose (+ to +) and shorting the two negative terminals, you're charging it up using the NiMH setting on your whiz-bang SkyRC MC3billion and not having any luck?

For a first post here, yours is one for the ages.

Ditch the first cell and don't worry about it. For roughly $6-$7, you can have a great cell, albeit a naked one and you won't have to worry about what might be 'behind door 3.'

As for the second cell, you should reset the PCB the way I suggested and if it doesn't work, ditch that cell.

I don't know what happened to your Thrunites, but you seem to be playing with fire drilling into a 3.6v li-ion cell.

Life's too short to be a 'Thrill Seeker,' don't be 'that guy.'

Chris

Some youtube videos are just out right dangerous, please dont do what the youtube guy is going.

Simplest solution here is try the reset as mentioned. If no worky, recycle it. Some things(like $5) are just not worth potentially burning your face off, or your house down.

My opinion best to start over, good cells are too cheap to take any risks(well tbh, even if the were $100 i would not be taking the risks seen in that video!)

Lots of good shops USA side and Europe if needed, also vape shops(good ones) can carry some decent cells as well.

:welcome:

Attempts to reset a tripped CID may result in a very dangerous cell - see my 3 posts in the thread "CID protection reset 18650" for further details.

Thank you so much for all of your answers!
I tried putting a good 18650 in parallel with the bad one but it still showed 0.0v after two 15s tries. I initially tried the Sky RC in NIMH mode because it was the closer I could get to having a controlled current flow to the cell. As you said, in the LiIon and LiPo modes, the voltage was too low to start charging.
Removing the protection circuit seems like a good idea but I do not trust my skill to do that kind of precise operations :sweat:. I think that I'll just dispose the cells and forget about them. As you said it is not worth the risk. I have 5 more 18650s which are more than enough for my needs
And the damage to the cells I think that may have been due to overcharging them and storing them at high voltages. I used a cheap wall charger which ended up overcharging them to about 4.26v and also using the built-in charger of the olight H2R which was stopping the charge at about 4.23V . That reduced the capacity of all my 18650 cells between a 10 and a 20% (and also, i guess, ruined the 2 cells that I mention in this thread). Yeah, I know, stupid mistake by my part. Now I have all of the stored at 3.75v and I never charge them higher than 4.15v.
The thread about resetting the CDI was very interesting also. Definitely I don't want to use a resetted CID cell now.
Again thank you for your messages, I hope that I answered your questions and justified my newbie mistakes
Kindly regards
Pablo

Pablo, thanks for the update. Ya, not a lot of monetary loss. If you don't feel comfortable removing the protection circuit or have any sleeves to shrink back on, then best just to move on. Look like its time to get a new charger. Best of luck.

Yes thanks for feedback, always good to hear back. Regarding your olight h2r, dont worry too much. Most chargers operate with a + 0.05/-0.05v, so 4.15v to 4.25v is actually in their spec. Yes it is better for the cell closer to 4.2v or a little bellow even. But 4.23v is not the end of the world, also on how your measuring that voltage, there is another potential variable.

I prefer to charge cells outside of devices if i have the choice, also when charging the h2r with cell in side.............i cant wear/use it on my head(well i guess i could with a 500m extension lead! now there is a sight). I simply swap out for new, slap used on a charger(figure of speech) and good to go straight away.

PabloVS said:

I tried putting a good 18650 in parallel with the bad one but it still showed 0.0v after two 15s tries.

Removing the protection circuit seems like a good idea but I do not trust my skill to do that kind of precise operations.

And the damage to the cells I think that may have been due to overcharging them and storing them at high voltages. I used a cheap wall charger which ended up overcharging them to about 4.26v.

Click to expand...

It's possible that the protection circuit tripped because the cell voltage is too high. In that case, resetting the circuit (as you tried) may not work, since it would immediately trip again due to the high voltage. Leaving it for a few weeks to self-discharge back down to 4.2v might work. Of course, the cell won't like sitting at 4.26v for several weeks.

^^^ Overcharge(overvoltage) protection normally turns off only the charge FET, not also the discharge FET, i.e. you should be able to discharge an overcharged cell. However, if you trigger overcurrent protection during such a discharge then some poor designs might get into a wedged state that requires manual resetting. But it's more likely that the circuit is damaged, e.g. by mechanical shock.

Interesting, I didn't know they were designed for that. That makes good design sense.

I don't have many protected cells; just some 14500's (for dumb AA lights) and a few 18650's I never use. Don't really see much use for them, as long as you take very basic precautions. Besides, most of my 18650 lights would likely come too close to tripping the current protection.