How can I tell When to recharge 14500's?
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Anders
Enlightened
Use a DMM
4.2V – 100%
4.1V – 87%
4.0V – 75%
3.9V – 55%
3.8V – 30%
3.5V – 0%
Its hard to tell by the output, many LED flashlights will begin blinking rapidly. i don't know if yours would.
Anders
4.2V – 100%
4.1V – 87%
4.0V – 75%
3.9V – 55%
3.8V – 30%
3.5V – 0%
Its hard to tell by the output, many LED flashlights will begin blinking rapidly. i don't know if yours would.
Anders
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moon lander
Enlightened
id say charge them any time thay arent full. from what ive heard, its not any worse to charge from half full twice than to charge from empty once. then you wont risk going below the critical voltage, plus you will always have a full battery when you want to use the light.
i used my mk2x for a while, then on low setting i noticed it going dim. switched it to high and it quickly turned very dim. took out the 14500 cell and it read 1.85v (way too low). After 2 hours, however, it came back up to 3.2v so i guess its not ruined, but id rather not let it get that low. i won't depend on my mk2x to inform me when the cell is low.
i used my mk2x for a while, then on low setting i noticed it going dim. switched it to high and it quickly turned very dim. took out the 14500 cell and it read 1.85v (way too low). After 2 hours, however, it came back up to 3.2v so i guess its not ruined, but id rather not let it get that low. i won't depend on my mk2x to inform me when the cell is low.
Thanks for the info. Just charged the pair on a WF-139. One battery was in the Rexlight, the other in the MKIIx. Both batterys read 3.95 and 3.93 before the charge. When the lights turned green I measured 4.17 and 4.16. MAybe I should have left ina while after it turned green?
Anders said:
Anders
Enlightened
bullpup: 4,16-4,17 are perfect, don't charge them more if you don't must have 100%, if you stop earlier than 4,2 your cells will last many more cycles and there aren't much more power in them if you charge them to 4,2.
Li-ion arent supposed to be trickled charged, in fact many users with WF-139 are concerned because their charger stop to late, a bit more than 4,2, be happy with 4,16-4,17.
Anders
Li-ion arent supposed to be trickled charged, in fact many users with WF-139 are concerned because their charger stop to late, a bit more than 4,2, be happy with 4,16-4,17.
Anders
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Thanks everyone. I got a lot of good info and feel better about the LIon battery. I know I need protected ones and will order some today. The last month five lights came into the house so I held of with the protect purchase.
Steve L
Flashlight Enthusiast
When using the low power setting it is very difficult to tell by eye because the current draw is low, so the voltage doesn't sag as much when the battery is depleted. When using the higher power settings it becomes much more apparent when the batteries are low, drawing more current and the voltage sags thus the light gets noticeable dimmer. Every once in a while switch to a higher setting to check the output. Still the only way to really know is with a DMM. The best advise is charge the batteries after use. They have no memory effect, so you can charge whenever convenient.
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trailstoride
Newly Enlightened
I'm a bit puzzled. My WF-138 charges my 10440's (AAA Lithium) to 4.3V as measured during the charge cycle. At 4.3V, the light goes green and over the next minute the voltage drops to 4.16V, and after about 5 minutes measures 4.14V.
Are my batteries overcharging? Going by the chart above, they are between 4.1V (87%) and 4.2V (100%) as soon as they rest a minute. That appears to be an OK charge level. My only concern is seeing the voltage on the charger rise to 4.3, before the charger goes green.
Are my batteries overcharging? Going by the chart above, they are between 4.1V (87%) and 4.2V (100%) as soon as they rest a minute. That appears to be an OK charge level. My only concern is seeing the voltage on the charger rise to 4.3, before the charger goes green.
SilverFox
Flashaholic
Hello Tailstoride,
Charging Li-Ion cells above 4.200 volts results in overcharging the cell. There is also some indication that very low current charging when the voltage is at 4.200 volts or higher can damage the cell. This is why there is such a tight control on the upper voltage limit and why the current should be shut off when it drops to a low value.
Overcharging damages the cell and reduces the cycle life of the cell.
This damage results in reduced capacity of the cell, and higher internal resistance of the cell.
Higher internal resistance results in a larger voltage drop under load. This voltage drop works both ways. When you apply a load, the voltage of an aged cell will drop further than that of a healthy cell. Also, when charging, a healthy cell will remain at the voltage it was charged to, where an aged cells voltage will drop.
A general rule of thumb is that when the cell is fully charged, removed from the charger and left to sit for around 10 - 15 minutes, its voltage should be over 4.0 volts. If it drops below 4.0 volts (this assumes you are charging to 4.200 volts) it is time to recycle the cell.
Tom
Charging Li-Ion cells above 4.200 volts results in overcharging the cell. There is also some indication that very low current charging when the voltage is at 4.200 volts or higher can damage the cell. This is why there is such a tight control on the upper voltage limit and why the current should be shut off when it drops to a low value.
Overcharging damages the cell and reduces the cycle life of the cell.
This damage results in reduced capacity of the cell, and higher internal resistance of the cell.
Higher internal resistance results in a larger voltage drop under load. This voltage drop works both ways. When you apply a load, the voltage of an aged cell will drop further than that of a healthy cell. Also, when charging, a healthy cell will remain at the voltage it was charged to, where an aged cells voltage will drop.
A general rule of thumb is that when the cell is fully charged, removed from the charger and left to sit for around 10 - 15 minutes, its voltage should be over 4.0 volts. If it drops below 4.0 volts (this assumes you are charging to 4.200 volts) it is time to recycle the cell.
Tom
nanotech17
Flashlight Enthusiast
To me the best way to detect 14500 unprotected to recharge is when your flashlight is not hot in the head then it's time to recharge 
Any thoughts?
Again I charged my Ultrafire 14500 in the WF-139. The light turned green at 4.17 volts. I took it out of the charger and let it sit for ten minutes. I measured the volts at 4.14. Should I be happy that it did not overcharge or should I leave it in a few minutes so it reads 4.20 after ten minutes?. Thank you.
Again I charged my Ultrafire 14500 in the WF-139. The light turned green at 4.17 volts. I took it out of the charger and let it sit for ten minutes. I measured the volts at 4.14. Should I be happy that it did not overcharge or should I leave it in a few minutes so it reads 4.20 after ten minutes?. Thank you.
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nanotech17
Flashlight Enthusiast
I use mine with dsd charger .
Full top up at 4.2v
Full top up at 4.2v
Weskix
Newly Enlightened
My protected cells from AW seem to top off at 4.04 in the DSD charger. Is the PCB kicking in too early? My 17670's charge up to 4.17V in the same charger.
it's better to terminate your charge at 4.1V if your charger will allow that option.
then charge to 4.2V when you need extra capacity. charging to 4.1v giving a margin of error.
depending upon brand of pcb, overcharge protection circuits will kickin about 4.25V. old pila's kicked in at 4.2V, protection pcb was used to terminate charge using dumb charger. new pila chargers are high recommended and will terminate charge at 4.2.
note as li-ion cells age, they will accept less of a charge. cell may charge up to 4.2 and terminate, but will quickly bleed down to resting voltage. what ever that might be....
for bare li-ion cells, yank at first sign of dimming. then quickly measure voltage a few cycles to determine if overdischarge is occurring. your goal is to yank before cells drops below 3.5V
then charge to 4.2V when you need extra capacity. charging to 4.1v giving a margin of error.
depending upon brand of pcb, overcharge protection circuits will kickin about 4.25V. old pila's kicked in at 4.2V, protection pcb was used to terminate charge using dumb charger. new pila chargers are high recommended and will terminate charge at 4.2.
note as li-ion cells age, they will accept less of a charge. cell may charge up to 4.2 and terminate, but will quickly bleed down to resting voltage. what ever that might be....
for bare li-ion cells, yank at first sign of dimming. then quickly measure voltage a few cycles to determine if overdischarge is occurring. your goal is to yank before cells drops below 3.5V
