PILA IBC RED BLINKING LIGHT

[tatasal]

I was charging two old 18650 laptop cells (steady RED on, charging) for about 20 minutes then suddenly one bay's RED(only RED) led started to blink. I tried to look in the owner's manual and the following was printed: No Batteries . . . Green on / Red fast blink
Charging . . . . . Green off / Red on
Full . . . . . . . . .Green on / Red off
Defective Cell . .Green on / Red fast blink
This is the first time it happened. I have lots high IR, defective and rejected cells already but never a BLINKING RED ONLY. I removed the cell and put it back then a steady red for a few minutes then the BLINKING RED ONLY came back. With the both cradles empty, it's back to normal green on/ fast red blink (NO BATT). What does this mean?

[tandem]

While it is a good charger, a diagnostic tool the Pila is not. I hope you mark the two cells A and B where A didn't blink and B did, or something similar, so they can be identified.

What was the starting voltage of the 18650 cells before you put them in the charger? What voltage is the cell - immediately out of the charger - which causes the unit to blink? 20 minutes later what is the voltage of that B cell. Does that cell cause the charger to blink when it is inserted into the other cradle? If A was left in the charger until completion, what was the final voltage straight out of the charger? What was the voltage of A 20 minutes and 2 hours later?

Keep some notes and report your findings; hopefully there are clues there.

[tatasal]

While it is a good charger, a diagnostic tool the Pila is not. I hope you mark the two cells A and B where A didn't blink and B did, or something similar, so they can be identified.

What was the starting voltage of the 18650 cells before you put them in the charger? What voltage is the cell - immediately out of the charger - which causes the unit to blink? 20 minutes later what is the voltage of that B cell. Does that cell cause the charger to blink when it is inserted into the other cradle? If A was left in the charger until completion, what was the final voltage straight out of the charger? What was the voltage of A 20 minutes and 2 hours later?

Keep some notes and report your findings; hopefully there are clues there.

Okay, here is the background. They are four individual Panasonic CGR18650DA, 2450 mAh cells from a laptop batt pack. Last night the first 2 cells (very low .71v and .67v starting voltage), I charged them, no problem till termination at 4.17v. Surprisingly it passed my initiation test. (completed the 5 min turbo run on my ZL SC600 with no premature step-down)
As I said before in some of my threads, I enjoy doing this, so don't ask me LOL.

Tonight, I loaded the remaining 2 cells ( at a lower starting voltage of .21v and .16v), and that RED ONLY blinking light happened. First on the left cradle. Removed the cell but the red blinking still continued. The remaining right cell eventually RED only blinked too. I pushed RESET (w/o the cells), normal green on/blinking red came back. I put back the two cells, steady RED came again, then after a while Blinked RED ONLY again. All cells are numbered, recorded.

[tandem]

What is the voltage of those two remaining cells right now?

[tatasal]

What is the voltage of those two remaining cells right now?

The 2 remaining cells voltages were: cell that started at .21v - ended at 2.59v ( start of red-only blink )
cell that started at .16v - ended at 1.59v ( start of red-only blink )

After the 2nd attempt ( of which the red only blinked again), I removed both cells and stopped the charging.

[tandem]

Ok, so the cells were brought up some distance in voltage, so it doesn't sound like the voltage alone is what the Pila is tripping on. Maybe cell IR goes awry when they've been deeply discharged for so long, that's just a wild guess.

I've never recovered cells quite so badly beat up; I throw out cells that look a lot better than the ones you have!

[45/70]

Okay, here is the background. They are four individual Panasonic CGR18650DA, 2450 mAh cells from a laptop batt pack. Last night the first 2 cells (very low .71v and .67v starting voltage).......

......Tonight, I loaded the remaining 2 cells ( at a lower starting voltage of .21v and .16v), and that RED ONLY blinking light happened.

Just a note of caution here. Any LiCo Li-Ion cell that has been stored, or been left at a voltage of less than ~1.5 Volts for any length of time, has likely suffered internal damage. There is no guarantee, but these cells that you've harvested that have OC voltages of less than 1.5 volts, are potential "time bombs".

These cells may seem to be OK, for now, but tomorrow, next week, next month, or...???, you could run into an unexpected "vent with flame incident". This is most likely to happen when attempting to recharge the cells, but could occur at anytime, during use or even when in storage. The damage caused to LiCo cells from under voltage, is permanent, irreversible, and cumulative, over time. Then again, nothing may happen, but I would highly recommend that you promptly dispose of/recycle any cells harvested, that read below 2.5 Volts, let alone 1.5 Volts.

Dave

[tatasal]

Thanks tandem and 45...

I never charge these cells unattended, with-in arms length away the whole time, checking the temp of the cell and the charger maybe every 5 min or so ( by hand). I only charge my li-ions when I use my laptop to keep me company. If I get tired before it gets full, I continue the next time, same procedure. The cells that I consider to be good enough (for me at least!) are kept in the fridge. The rejected ones are put atop a wooden table.

As for the 'vent with flames' scenario, I'm aware of that possibility, although I've yet to read someone's deeply discharged batt pack or cell 'vent with flames' while left uncharged, unused.. Here in my place proper disposal of ANY kind of battery/cell are unheard of. They end up in garbage landfills.

Going back to the RED only blinking of the Pila, what do you think is the reason for that? Just curious. ( I know the cell has 'consumed' its useful life).

[tandem]

Without a diagnostic tool (such as a hobby charger that can report on internal resistance) probably all we can do is speculate. The Pila is designed to charge only li-ions and it may be that the IC it uses is hard coded to expect cells to be within a certain range of conditions.

Given that we can only speculate, to me it seems not only prudent but mandatory to respect the warning the Pila is giving you. It believes the cells are damaged, so go with that. Discharge them if you can, safely, and toss them.

I'm guessing high internal resistance but literally that's just a W.A.G.

Personally I would fear cells that venture that close to 0 volts; is it possible for such a cell to have been reverse charged sometime in its life? I don't know the answer to that but would expect any cell that has been close to 0 must at least be suspected to have been treated very badly indeed. A healthy cell does not self-discharge much at all, so something about how the cell was used in the pack smells bad to me.

Cells in series (laptop packs, check) certainly can develop a situation where a weak cell gets pushed into a reverse charge situation; it is exactly this scenario that has been implicated in some flashlight explosions. Proven or not, there's reason to be cautious.

Surely there must be some better laptop cell harvests out there!

Good luck, stay safe!

[45/70]

As for the 'vent with flames' scenario, I'm aware of that possibility, although I've yet to read someone's deeply discharged batt pack or cell 'vent with flames' while left uncharged, unused..

Well, that's probably because nobody plays around with cells that are over discharged LOL!

When a battery pack is "deeply discharged" as in a laptop, the cells, provided they are in good condition, will read 3.5-3.6 Volts. This is because of the protection circuitry incorporated. When the protection circuit trips on a protected cell, such as we use in our lights, the cell will read a similar OC voltage.

It's really only worn out cells that drop to very low voltages. A cell in good condition with an OC voltage of 3.5 Volts can be put away for months, and loose very little voltage. Again, it's only the bad, worn out cells that self discharge at a high rate. These cells usually don't perform very well either.

I'll leave it at that. Do be careful though.

Dave

[45/70]

Cells in series (laptop packs, check) certainly can develop a situation where a weak cell gets pushed into a reverse charge situation; it is exactly this scenario that has been implicated in some flashlight explosions. Proven or not, there's reason to be cautious.

Actually it's not the reverse charging scenario that is the problem, with old LiCo cells. I'm not saying it isn't a problem, it is, but not as serious as reverse charging lithium primary cells. LiCo cells might "vent with flame" if reverse charged. If the cells are all pretty much depleted though, maybe not. With lithium primary cells, a "vent with flame" situation is almost guaranteed.

The problem with old, or over discharged LiCo cells, is the potential for copper shunts to form across the separator. These shunts can form when a LiCo cell's voltage drops to a low enough level. It doesn't matter how old the cell is. They can form in a new cell. The older the cell is though, the more likely these shunts are to form, at low voltages.

Normally, you hope anyway, these shunts will simply cause abnormally high self discharge of the cell. If these shunts are substantial enough to carry high current however, you have heat, oxygen, and a very volatile solvent based electrolyte, all contained in a cylindrical metal enclosure, with little tiny vents at the positive end. Not a good recipe.

Dave

[tatasal]

I'm not sure, but I'd like to ask if venting with flames/explosions has only happened to sub-standard no-name pretentious brands?
Has it happened to major, industry-standard brands like Sanyo/Panasonic? Try to check Panasonic's 18650 specs...they even charge their lithium-ion 18650 up to 12v as a safety buffer to meet their own standards (among other numerous safety requirements)...sorry I can't find that link right now.

[ElectronGuru]

While the latest pannys are robust, no brand should be considered impervious. Better condition and quality control just gets you better odds.