Hello, I have a Ultrafire Q5 CREE x3 LED 700 lumens flashlight model #WF700F. It takes two 18650 batteries and when I pull the discharged batteries out of the light, one of the batteries (tail battery) will not accept a charge on my Ultrafire WF-139 charger. It appears that the flashlight discharges the battery too much. Has anyone heard of this happening before?
Ultrafire flashlight killing my 18650 cells
- Thread starter CPerry
- Start date
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Each of your batteries have a protection PCB.
Your flashlight, as most ones and not only Ultrafire's, discharges the batteries until one off them gets its protection triggered to prevent an excessive discharge.
The issue is not the batteries neither the flashlight but your charger which is unable to detect the batteries whose the protection triggered.
Most of the chargers you can find at DX work quite better than Ultrafire's.
This one is very cheap but it works perfectly: http://www.dealextreme.com/details.dx/sku.6105
If you have an ajustable power supply, you can use it to reset the battery protection. Firstly, set the voltage to 4.2V and the maximum current to 600mA, then plug the negative pin of the power supply to the negative side of the battery, then link the positive pin and side for a few seconds. This is enough to reset the protection PCB and makes the battery able to be charged by any charger.
Your flashlight, as most ones and not only Ultrafire's, discharges the batteries until one off them gets its protection triggered to prevent an excessive discharge.
The issue is not the batteries neither the flashlight but your charger which is unable to detect the batteries whose the protection triggered.
Most of the chargers you can find at DX work quite better than Ultrafire's.
This one is very cheap but it works perfectly: http://www.dealextreme.com/details.dx/sku.6105
If you have an ajustable power supply, you can use it to reset the battery protection. Firstly, set the voltage to 4.2V and the maximum current to 600mA, then plug the negative pin of the power supply to the negative side of the battery, then link the positive pin and side for a few seconds. This is enough to reset the protection PCB and makes the battery able to be charged by any charger.
Thanks for the reply lermite. So, you are saying that the charger doesn't detect that the protection circuit on the Ultrafire cells has been triggered?
I have charged AW 18650 cells that I use in my Jetbeam RR-2 Raptor that have been discharged to the point where the protection circuit has been triggered and the AW cells charge fine on the same charger.
I'm confused as to why the Ultrafire cells don't charge when fully discharged but the AW cells do on the same charger.
I'd like to reset the protection PCB but don't have an adjustable power supply.
I have charged AW 18650 cells that I use in my Jetbeam RR-2 Raptor that have been discharged to the point where the protection circuit has been triggered and the AW cells charge fine on the same charger.
I'm confused as to why the Ultrafire cells don't charge when fully discharged but the AW cells do on the same charger.
I'd like to reset the protection PCB but don't have an adjustable power supply.
Bullzeyebill
Flashaholic
Welcome to CPF. Dozens of threads on LiIon chargers here. Most LiIon chargers will kick start a protected cell that has normally turned off due to underdischarge. I have been using LiIon's for years and use a Yohoo-122 charger that I purchased from e-lectronics, one of our CPF people. Get a reasonably priced Liion charger like the Yahoo, and then do some more shopping for better if you think you need better. In the meantime monitor your cells carefully so they do not "turn off". Check voltage with your DMM so they do not fall below 3 volts resting. Don't have a DMM, then do not use LiIon cells.
Bill
Bill
I tried to keep my explanation as simple as possible but in fact, the PCB protection of a battery can reset itself if the flashlight if set off or the battery is removed from it soonly after the protection triggers.
This delay may vary depending on battery brand, model and else, but even an AW protection is not able to reset itself if the battery is kept in use for a while after it triggered.
This delay may vary depending on battery brand, model and else, but even an AW protection is not able to reset itself if the battery is kept in use for a while after it triggered.
I am not sure it is the protection of the battery. My WF 139 charger will not start to charge unprotected batteries if they have been drained too low. I have however found out that the charger gives a little current, even if the light is green. If I leave the battery in the charger for a while, it will get up to a voltage where the charger will start to charge properly. May be you will have to take out the battery, and insert it again for this to happen.
CPerry: what batteries do you use?
WF-139 should reset the PCB protection without problems.
WF-139 should reset the PCB protection without problems.
If it should, why doesn't it do?
I tested many batteries:
- 6 x 18650 Trustfire 2500 blue
- 8 x 18650 Trustfire 2400 black
- 4 x 18650 Ultrafire 2600 magenta
- 2 x 18650 Ultrafire 3000 red
- 1 x 18650 AW 2200
- 3 x 18650 AW 2600
- 6 x 16340 Trustfire 880 gray
- 4 x 16340 Ultrafire 880 gray
- 4 x 16340 Trustfire 880 white
- 4 x 16340 Trustfire black
- 4 x 16340 Ultrafire 1000 blue
- 6 x 16340 AW 750
I tested each battery several times by discharging it into different sets of resistances. The currents are: 0.4A, 1.2A, 3.5A, 5A, and for a few of the batteries: 1.7A, 2.4A.
Each time, I let the battery to discharge until its protection triggers. Sometimes, I remove the battery just after the protection triggers and sometimes, it get reseted by itself. But I often forget the battery for one hour or more and in this case, the protection remains activated even after the battery is removed. I checked it with every of my tested batteries, and my test at 5A is one of the hardest the batteries can manage.
How could a flashlight working with two 18650 could be harder than my tests, and how could it result differently than my tests?
I tested many batteries:
- 6 x 18650 Trustfire 2500 blue
- 8 x 18650 Trustfire 2400 black
- 4 x 18650 Ultrafire 2600 magenta
- 2 x 18650 Ultrafire 3000 red
- 1 x 18650 AW 2200
- 3 x 18650 AW 2600
- 6 x 16340 Trustfire 880 gray
- 4 x 16340 Ultrafire 880 gray
- 4 x 16340 Trustfire 880 white
- 4 x 16340 Trustfire black
- 4 x 16340 Ultrafire 1000 blue
- 6 x 16340 AW 750
I tested each battery several times by discharging it into different sets of resistances. The currents are: 0.4A, 1.2A, 3.5A, 5A, and for a few of the batteries: 1.7A, 2.4A.
Each time, I let the battery to discharge until its protection triggers. Sometimes, I remove the battery just after the protection triggers and sometimes, it get reseted by itself. But I often forget the battery for one hour or more and in this case, the protection remains activated even after the battery is removed. I checked it with every of my tested batteries, and my test at 5A is one of the hardest the batteries can manage.
How could a flashlight working with two 18650 could be harder than my tests, and how could it result differently than my tests?
Bullzeyebill
Flashaholic
Lermite, I have been using 18650's for a few years now. I have two protected ones and I have never purposefully discharged them to see if the protection circuit works. When the undervoltage circuit does kick in it is my fault because I have not been monitoring them. I closely monitor all of my Li Ions, and have to because they are mostly unprotected. As noted earlier, the protection circuit is there as a last resort, and the best procedure for working with LiIons is to charge them up before they drop below 3.5 volts or so resting. Just some advise, don't run them down so low anymore, at least not on purpose.
Bill
Bill
Many flashlights don't include a protection function.
The ones that are in direct drive don't need it, but what about the ones that are perfectly regulated? How the voltage of the battery can be measured while using a flashlight, during a long walk at night by example?
The Liteflux's and the flashlight modded with a Taskled driver can manage the battery voltage but most of others can't. With a Fenix P3X, Aurora AK-P7-3, and most of 2x16340 flashlights, there is no choice to rely on the batteries protection to prevent an excessive discharge.
Perhaps you always carry a multimeter and check your batteries voltage every five minutes?
In more, the purpose of the tests I talked about was the test of the protection but to measure the battery capacity, and the only mean to do it is to discharge the battery from the highest to the lowest voltage it can manage without damage. The maximum runtime of a flashlight is obtained by using the entire range of voltage of the batteries too.
The ones that are in direct drive don't need it, but what about the ones that are perfectly regulated? How the voltage of the battery can be measured while using a flashlight, during a long walk at night by example?
The Liteflux's and the flashlight modded with a Taskled driver can manage the battery voltage but most of others can't. With a Fenix P3X, Aurora AK-P7-3, and most of 2x16340 flashlights, there is no choice to rely on the batteries protection to prevent an excessive discharge.
Perhaps you always carry a multimeter and check your batteries voltage every five minutes?
In more, the purpose of the tests I talked about was the test of the protection but to measure the battery capacity, and the only mean to do it is to discharge the battery from the highest to the lowest voltage it can manage without damage. The maximum runtime of a flashlight is obtained by using the entire range of voltage of the batteries too.
ergotelis
Enlightened
Is there any possibility of a short circuit? Something like that might kill the pcb protection. It has happened to me. Then batteries cannot be charged at all.The only way,but not safe, to operate them is to remove the pcb protection.
Bullzeyebill
Flashaholic
LOL. Thank you for the humor.:thumbsup: No, but I pretty much know how long my cells will last when I take walks, often using freshly a charged cell, or cells. Some of my high amp incans are used with AW's soft start 3 level switches, so I don't have to run them at highest level, conserving the batteries. The only times I have trouble with the LiIon cells is when someone elese is using my lights, and let them run till they are dim. Then I pay real close attention to them (the user and the cells).
Bill
Where did you buy your WF-139? Is it from AW or DX? My AW WF-139 resets all my cells without problems. And I have even more than you
My WF-139 comes from DX but since I tested it (current and voltage during a charge), I don't use it any longer.
A good charger must charge with a constant current (~C/2), then, when the voltage reaches 4.2V, it must maintain a constant voltage (4.2V) while the current decreases.
WF-138 and WF-138 only charge with a constant current until 4.25V or 4.3V. They bypass the second phase of the charge.
That's why I use Mystery balanced chargers, Pila IBC and the nonames from DX instead of Ultrafire's.
Ultrafire can make awesome flashlights, but their batteries and chargers are nothing else than crap.
The batteries I listed are only the ones whose I tested the capacity, but I didn't test every of them.
I own more than one hundred batteries
A good charger must charge with a constant current (~C/2), then, when the voltage reaches 4.2V, it must maintain a constant voltage (4.2V) while the current decreases.
WF-138 and WF-138 only charge with a constant current until 4.25V or 4.3V. They bypass the second phase of the charge.
That's why I use Mystery balanced chargers, Pila IBC and the nonames from DX instead of Ultrafire's.
Ultrafire can make awesome flashlights, but their batteries and chargers are nothing else than crap.
The batteries I listed are only the ones whose I tested the capacity, but I didn't test every of them.
I own more than one hundred batteries
Last edited:
Outdoors Fanatic
Flashlight Enthusiast
Ditch the WF-139, get the YOHO-122.
Tempsho
Newly Enlightened
- Joined
- Jan 25, 2009
- Messages
- 55
Even though the Pila IBC is 2-3 times more than the YOHO-122, which of the 2 would be a better choice?
Outdoors Fanatic
Flashlight Enthusiast
The Yoho is better and faster. But it can't be used to charge 16340 LiCo cells, though.
