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That looks like an open circuit reading of the meter, i.e. no real voltage was measured. My meter reads 0.000 with nothing connected.
Some cells have an internal protection device to open the circuit path in the event that the cell gets too hot, others will open the circuit device if the internal pressure gets too high.
Dell wouldn’t want any fires to spoil their rep, so they may have a self discharge mode to drain the pack in the event of any cell issues. The BMS chip in some Ryobi packs has this “feature”.
So they need to be recycled; they are likely okay to sit on your bench, but it is not worth the risk to try to reuse them. If you attempted to recharge them, then that is what could set them off.
To charge old cells is dangerous. They heats up and……
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We lived near the Willamette for 6 yrs.
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I tend to work on the principal that if they don`t get warm when charging then they`re safe, if they do, then it`s time to discharge them, thank them for their service and recycle them.
things i learned so far:
warm charge = bad
loss of electrolyte is a common cause of capacity loss = can be bad
( i was assuming no physical damage, or bad charge/discharge damage - just normal use )
thx
wle
Yes, and also check to see if they’re warm when just sitting idle (after charging). I’ve had a couple of heaters do that (fairly new Samsung 30Q). Turned out they were suffering from very high self-discharge, dropping about 0.1v per day. They felt slightly warm to the touch. Must have been a small internal short. So, definitely in the unsafe category.
How old is old for Li-ion? My oldest are 3yo.
also i would add “the charge that never ends” - though if i am not mistaken, cells that do that, are also getting hot
though heating may depend on the charge current…
wle
Green wrapped cells and all dead. I did put one in a xtar X4 and the meter read 0 so I pulled it immediately.
These are 10+ yrs old.
…Love the Willamette
i would also suspect that “0 volt” cells are really cells whose protection circuits have disconnected
probably due to the real voltage being under some “do not charge these any more” threshold like .9v or 1.0v
wle
I`v had that a few times with NiMH batts, I tend to get the opposite with Li-ion, they can be really low, put them in the charger and they`re at 4.1v in less than a minute! they`ll read full but hold almost nothing, sometimes i`v even wondered if someones swapped the insides with a 10180 cell LOL
As a general rule, I would refresh my cells (meaning buy new ones) every 5 years. I do the same with car batteries. Yes I know they will last longer then five years but following this basic rule ensures you always have new batteries. At $5 a pop, its not that much money even if you have 20-30 cells.
yes that is another symptom of being worn out - the too-fast charge and low capacity
i think my phone battery is doing that
wle
Na, they’re just old and worn out, with high internal resistance. That’s what causes the voltage (at the charger) to spike right away. I find that once you start to notice lithium-ion cells getting bad, they rapidly deteriorate after that. Eventually, ending up as what you state.
Basically, you have a lot of cycles until they get down to about 70% capacity. After that, there’s only a few cycles left until they get useless.
I “recycle” my old (high IR) 18650s into my outdoor solar LED lights I have along the side of my pathway to my garage (and a few other places around my barn). They don’t need a lot of power to run motion sensor lights, and tend to run a few years before I flip them out and replace them (again) with my stash of “old” 18650s I save up over time. I have rebuilt those solar lights several times the last 5 years and many laptop/power drill pulls are in them and doing fine.
I put mine in my doorbell 
one of my chargers does the same, even with new healthy cells, for some reason when I put empties in, it would “charge” them in seconds, i take them out and put right back in, and they charge properly,
At $5 pop, don’t fool around with old batteries.