All I know is when I stuck those really drained batteries in my d4 it brought them back to 3. something volts really quick and got them charged with very little heat coming from them. So maybe I lucked out. 
When I placed the battery in the vc4 it shows as NiMH and then shows 0V. Tries charging but will always return to null.
toasted
I wonder if it is protected. Because I might rip the protection off and see if the cell is still in healthy voltage.
if not just throw it away
No protection. i don’t like pcb. my sis was using the light. thats why that happened…
You really should find a multimeter and test the voltage, just in case it’s fine and for some reason the charger has a problem.
Throw away nothing until you verify that its faulty.
It’s a lesson you have to pay: “Don’t give any tech that you care about to a woman” 
Or it might be that your K40M is faulty!
nah its got nothing to do with the light. i accidentally mixed up 2 NCR18650B with a single NCR18650PF… I would replace the batteries every half hour of use. but since my sisters were using it till the higher high output were low i guess thats where the fault is…
Nothing has been dispose of as of yet…. I don’t own a multimeter, and the charger is fine…
Yes, but how can you explain that the low voltage warning was not activated on the light!. I thought you can’t use K40M “till the higher high output were low” you should get some warning before that! no? Also how do you explain that mixing B and PF cells would cause so huge load and drainage on PF cell!
Xtar SP1 also claims to resque over discharged batteries.
http://www.xtarlight.com/05-chanpin/p-001-1.asp?styleid=293
And it will not “diagnose” your batteries to be NiMH, because it’s a LiIon-only charger.
edit: and maybe M4D M4X can give you a coupon to ease the pain.
ctually i have no idea… it worked for me maybe my sister ignored it but only returned the light once it couldnt produce enough light
Totally agree with you now!
My advice is not totally safe but it will work 100% because its new battery. Just take 9V battery and connect it with your PF just for few seconds, and do it 5-6 times. PFs are hibrid battery and should handle it just fine. That way you will raise voltage to 2+ volts and yor charger will recognize it. Do it outside and watch carefully on + and - that is in correct order
I will try ASAP… So + side to - or - side to + side?
Just in parallel + to + and - to - also minus on 9V is the bigger one
OKAI! THANK YOU!
Hope it will work, just tell us results
If the battery won't hold a charge it's dead, period. Trying to recharge it knowing that it won't even hold 1.5v is just asking for trouble. The reason it won't charge up and is self-discharging is because shunts (small short circuits) formed inside the cell; if you do try and force charge it you could put enough energy in there to cause the cell to heat up significantly and possibly vent.
Whatever you do, do it outdoors and remember — don’t inhale if it vents.
What gets damaged is a very thin film of something like Gore-Tex membrane — microscopic pores that let the two different chemicals on either side interact to make electricity flow.
The damage is not a sudden event, it’s a degradation of that membrane, either the texture gets damaged, or crystals grow on one side of it and as they grow they can slowly poke a hole in it.
The sudden event is the result of having had the damage develop inside the cell due to mistreatment — overdischarge, overheating, thermal cycling, dropping, looking at it crosseyed if it’s a fake — or just damaged by being made in dirty conditions where metal scraps or crap can be inside the cell affecting how it behaves.
Lithium-ion cells are not inherently safe. They are safe to the extent they’re made right and treated right.
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P.S., and in reply to
You would be surprised if you met some of the people who contributed to the best tech you can buy hereabouts.