Possible causes for Li-Ion rechargeable batteries to fail.
- Thread starter Greg G
- Start date
Black Rose
Flashlight Enthusiast
What brand?
Mr Happy
Flashlight Enthusiast
Define "fail". You don't really say what the problem was.
This latest one shows about 1.5 volts, and won't take a charge. Were put into the light @ 4.2 volts, and just sat on the nightstand.
On this latest failure the light held 4 batteries in series. One failed and the light would not function.
I haven't done anything to this battery, but tI removed the PCB on the first one that failed thinking it was the culprit but the battery would still not charge.
On this latest failure the light held 4 batteries in series. One failed and the light would not function.
I haven't done anything to this battery, but tI removed the PCB on the first one that failed thinking it was the culprit but the battery would still not charge.
Mr Happy
Flashlight Enthusiast
Hmmm. I guess I'll let someone with more experience of Li-ion respond. It strikes me that four in series is an unusual configuration. So it may be something about the light, or it may be something about the charging.
csshih
Flashlight Enthusiast
some chargers will not even attempt to charge a li-ion discharged to 1.5V. I'm curious as to how it got there.. ther protection circuit would trip long before that happened. did this occur overnight?
DM51
Flashaholic
If that cell is reading 1.5V, it cannot be a protected cell, or the protection circuit has failed. Using unprotected Li-Ion cells in series is really asking for trouble.
You should NOT attempt to recharge it.
What are the other 3 cells reading?
What light is this that uses 4s Li-Ions? The max voltage is 16.8V, which as Mr Happy says, is fairly unusual.
As others have said, more details would help.
You should NOT attempt to recharge it.
What are the other 3 cells reading?
What light is this that uses 4s Li-Ions? The max voltage is 16.8V, which as Mr Happy says, is fairly unusual.
As others have said, more details would help.
SilverFox
Flashaholic
Hello Greg,
I think you should pop the cell that is reading 1.5 volts on the charger for about 30 seconds. I have seen some protected cells show that voltage when the protection circuit kicks in. If the protection circuit has tripped, this brief charge should reset it and you will end up with normal voltage. If this doesn't work, don't charge it.
On the information given..., I think there may be a drain on the system. This may be from the flashlight, or possibly from a malfunction in the protection circuit.
Other than total abuse and heat, Li-Ion cells degrade by oxidation of the internal components by the electrolyte. The oxidation potential is greatest at full charge, and at full discharge. The mix of the electrolyte varies between manufacturers, and batches, giving different performance for the various cells, but over all, the life of the cells has been increasing.
Tom
I think you should pop the cell that is reading 1.5 volts on the charger for about 30 seconds. I have seen some protected cells show that voltage when the protection circuit kicks in. If the protection circuit has tripped, this brief charge should reset it and you will end up with normal voltage. If this doesn't work, don't charge it.
On the information given..., I think there may be a drain on the system. This may be from the flashlight, or possibly from a malfunction in the protection circuit.
Other than total abuse and heat, Li-Ion cells degrade by oxidation of the internal components by the electrolyte. The oxidation potential is greatest at full charge, and at full discharge. The mix of the electrolyte varies between manufacturers, and batches, giving different performance for the various cells, but over all, the life of the cells has been increasing.
Tom
The light is a penta Cree mag with a green Shark. It was the first light I built using multiple Crees. R2 WD emitters from cutter and the Vf of the series was slightly above the voltage of the battery pack. No driver problems. No problems of any kind except for this battery dying.
I put the battery in my modded WF139 and let it sit for about 15 minutes. No joy.
I put the battery in my modded WF139 and let it sit for about 15 minutes. No joy.
