Yeah, if you “brick” a cell, usually protected, a dumb charger that doesn’t know any better will still try applying voltage across it, and leakage can slowly build up the cell’s charge to the point where it resurrects. Regular “smart” chargers will see the cell as dead and not even bother.
Dunno if unprotected cells can drop to 0V and, well, not burst into flames.
Yes they can, I managed to do just that 2 days ago :person_facepalming:
I don’t think it can burst into flames if it has 0v, can it? I accidentally bled a cell down to 0.7v, and the C412 gradually brought it back up. Never got hot, and the cell works fine.
I was never tempted to try it. 
Some cells can hit 0v and be revived. I’ve found some in tool and laptop packs and recovered them. Once tool packs get below a certain voltage a mosfet opens up to drain the pack indefinitely so it can’t be recharged. And I’ve had some cells get run to 0 volts in some lights that I recovered.
It resurrected one of my Panasonic NCR18650B battery that was drained by a flashlight down to between 1.5V and 2V. Other chargers of mine (Liitokola 202, 500 and Zanflare C4) wouldn’t charge it.
Ok guys I just got my new C4-12 Miboxer and I am thinking it may be the actual 30Q button top cells that are causing the high milli ohms. Just put an LG HG2 (might have a slight button top to them. I’m not 100% sure, but they are unprotected.
LG cells were getting 32 ohm readings. 30Qs were reading anywhere from 300+ - 65.
I will post some pictures of the LG cells and the 30Q tops in a minute
Check to see if the percentage changes when you manually set the charge rate. That was the wierd software thing the other charger was doing.
It makes sense to me Mikeadoo that if the only cells giving the ‘crazy’ IR readings are the 30 Q button tops…. then the problem has something to do with those cells.
here are the 30Q and the LG tops. Also Jason when I let the charger charge the 30Q at 2A for 5 mins the percentage didnt go up at all. I pulled the cell back and let auto do its thing and it went up from 84% to 93%. Also got the 999 again ONLY with the 30Q.
I dont understand all these crazy high ohm things…… weird. 700, 400, 200 then 66?
What was the voltage on those cells when you inserted them into the charger?
I actually just was thinking about that. They were 3.9V. Maybe that’s too high to charge them?
I think it’s just those cells. Like I mentioned a few days ago, using those same 30Q button top cells from Richard, my C4-12 gives fairly high and inconsistent IR readings, although maybe not as widely inconsistent as yours.
But are you still seeing a drop in % when you change charging rate, like you saw with your previous C4-12?
Not sure if its pertinent but my Miboxer C-2 4000 gives extremely high IR readings on any and all button top batteries that I’ve charged with it. Consequently they are charged at a snail’s pace.
YES. It just dropped from 84% to 41% just now.
“41%, 26 degrees C, 533 ohm and showing 4.20V”
After using my C4-12 for a month, I just wanted to report that I’ve had no issues whatsoever. It doesn’t show an internal resistance above 100mΩ for any of my protected button top cells, and charging is always very fast. It’s replaced all my other chargers (except for the Lii-500), and now the only other ones I’m interested in are the Gyrfalcon All-88 for my GT’s cells, and the SkyRC MC3000 (and maybe another C4-12) .
This is my second charger. Thought it was an internal problem. Only cells I have that are above 100 are my NCR18650B protected cells. I’ve had them for over a year or so and used them pretty heavily so I’m guessing that has something to do with it?
My brown LG HG2 cell (I think) is at 32 pretty consistently. That’s what it’s at right now.
NCR18650B are bouncing around like mad also in this charger. 381, 524, 615 104 on and on. They are freshly charged a couple days ago on the D4 though while I was waiting on my new C4 12. Also a bit longer than all my other cells protected or not.
Just noticed my LG cell was charging at 3 amps. Turned it down to 1.50A. 3A is a bit much I think. What do you all think?
I don’t think this particular charger design likes anything with a button top. I can make my charger duplicate Mike’s by using a protected Panny B cell. I can keep messing with the connection and make it read 999 and then it acts really weird just like Mike’s does. Then when it makes a good connection it’ll read something like 85 milli ohms and start charging normal.
I guess I haven’t noticed before because I typically only charge my bigger 26650 and 26350 cells which are not button top.
So Mike, my suggestion is to put one cell in at a time and mess with it till the milliohm readings are low, like well under a hundred milliohm for the 30Q.
Can you do that or will certain cells never give you a low resistance reading?