Quality issues with UltraFire 18650

[SilverFox]

AK645 sent me 2 UltraFire 18650 2400 mAh cells to test. These are protected cells.

I opened the package and checked the voltage of the cells. Both were below 0.1 volts. I wondered if the protection circuit had kicked in, but that would mean that the cells had self discharged. How old are these 2400 mAh cells anyway? Perhaps AK645 can answer that question.

I put the cells in my Pila IBC charger to charge them up. The Pila IBC refused to recognize them or charge them. At this point I contacted AK645 and told him that he should send them back for a refund. At the same time I tried to recover the cells by charging them at 0.1 amps. The voltage gradually rose to the point where the Pila charger would recognize them and charge them.

The cells warmed up on the Pila charger, so I moved it outside as a safety precaution. After a couple of hours I pulled the cells and decided to discharge them. The cells would not sustain over 0.1 amps. When I exceeded that current, they immediately shut down.

I told AK645 that the next step would be to remove the protection circuit and check out the bare cells. He told me that he was not planning on sending them back for a refund, so I should proceed.

I removed the protection circuit and did a 2 amp discharge. The initial cell voltage was 4.0 volts, so I did not expect full capacity. During the discharge the cells heated up to 130 F and were continuing to heat up at the end of the test, and the discharged capacity came in at around 1150 mAh.

Since I started with cells at roughly 80% of full capacity, I was expecting more from these cells. 80% of 2400 mAh is 1920 mAh. My 1150 mAh works out to around 60% of the capacity.

Not only did the protection circuits go bad, but the cells also went bad.

I see UltraFire cells mentioned from time to time. Is this an isolated incident? Have others had "issues" with these cells?

Tom

 

[WildChild]

No issue with the 2 I bought... They were 3.85V when I received them. They now have 1 cycle each and they never heated during discharge and charge (With the UltraFire WF-139 charger). I carefully monitor them during charging as I wasn't really sure of their quality. I think someone else mentionned that 1 out of the 2 he received was DoA like this. I use them in a Wolf-Eyes light that pulls around 950 mA on them. And... I probably won't buy those anymore if there are too many issues like this. Maybe the protection circuit failed and discharged completely the cells, killing them? Are the batteries you tested those with the gray shrink wrap and button top?

 

[WildChild]

If mines were right when I received them, should I trust them?

 

[LEDcandle]

I haven't done any runtime tests with the Ultrafires (to at least get a rough gauge of their capacity) but I did receive 1 dud 17670 that was 0.1v, but DX was very nice to send me another batt in my next order without having to return the old one.

I removed the protection circuit (even accidentally burnt my thumb when the protective strip touched positive and negative, causing a short) and the bare cell registered at 3.8v and seemed ok. I charged it up to 4.18v and it can be used.

Not sure how much capacity all my Ultrafire cells have though. I don't have any battery testers but a light runtime test should have a rough gauge.

 

[matrixshaman]

I've got a protected blue label UF 18650 in a high power signle cell Cree light that draws about 1.5 amp on high and never any problem with it. No noticeable self discharge. That's the only UF 18650 I have.

 

[ak645]

Hi Tom,

Thanks for the write-up.Both cells were purchased and shipped directly from LightHound to SilverFox.So no idea how long they were sitting around.

I had asked Tom to take a look at these because I was having some wonky results with mine.I did not tell Tom about any of my issues so his judgement would not be biased.

Like Tom my cells would not charge on the IBC charger.I pulled out my DSD and that worked.Took almost 10 hours to do a complete charge.Unfortunately I did not think to test voltage before charging.DOH! Thereafter they worked in the IBC.I have read one other post about recieving his UltraFire cells in a low charge condition.

I am using mine with a ROP/LO bulb which draws about 2 amps at 7.2volts.After the initial charge on the DSD and subsequent charge on the IBC the beam was weak and yellow.After the third and fourth charge it became much whiter and brighter. After the sixth charge the protection circuit on one of the cells tripped after one minute of run time.I revived it on the DSD and both cells have been working well ever since.

I bought the UltraFires to replace some AW cells that shorted out after one of those stupid little magnets shifted inside the light.I was really hoping for some good results with these as they were the only button top protected 18650s I could find.Oh Well.

I am no expert but I think these cells may have been permanently degraded by sitting around too long in a state of excessive discharge.

Andy

 

[WildChild]

I just saw that AW now has button top 18650 cells! Since friday I think... Next time I have to buy 18650, they will be from him. But it may take a long time if the UF ones don't die quickly, since they were good when I received them. By the way, I got mines from DX.

 

[ak645]

WOOHOO about freakin time.Thanks for the heads-up,WildChild! I'll finally get to run my ROP/HO lamp.

Andy

I just saw that AW now has button top 18650 cells! Since friday I think... Next time I have to buy 18650, they will be from him. But it may take a long time if the UF ones don't die quickly, since they were good when I received them. By the way, I got mines from DX.

 

[Windscale]

All my 18650s are UF. So far I had one dud cell. It was easy to tell as the light started green in the UF139 charger. Even with fully charged cells, the light will start red and then turn green. That was a blue one which I returned and exchanged. I have 4 silver ones (the latest) and they all seem to work properly but their diameter is a wee bit bigger. Still fitted my 18650 lights fortunately.

 

[ak645]

Hi Tom,

Does this mean the PTC circuit is missing/nonfunctional?

Andy

 

[ak645]

I attempted an informal capacity test on my two UltraFire batteries using my ROP/LO bulb which draws 1.9 amps.

At 58 minutes the light went out.Checked with my Fluke meter.One cell was at 3.47 volts the others protection circuitry had tripped.I revived the dead one on the DSD and voltage measured 3.49.Put them both back in the light and within one minute tripped again.

So capacity is somewhere north of 1900mah I know not where.Probably nowhere near the claimed 2400mah though.And the IC on one of these cells is defective.

Andy

 

[scott.cr]

I recently received four of the protected Ultrafire 18650s from DX and at least one was bad. I also removed the protection circuit as an experimental measure and the cells had limited usefullness. They've since found their way to my local household hazardous waste collection site.

 

[SilverFox]

Hello Andy,

The PTC is set for higher temperatures.

Healthy cells can withstand a 1C discharge without heating up. My alarm came because I was at less than 1C and the temperature was getting up to the point where degrading damage is done to Li-Ion chemistry.

Tom

 

[SilverFox]

Update:

I received another cell and this one worked. So, out of 3 cells, two had the protection circuit fail and one worked.

I removed the protection circuits from the two bad cells and decided to run a comparison of the 3 cells at a 1 amp draw. The problem is that all three cells came in at different capacities. I will post a graph of this later.

At any rate, the one cell that worked came in well under the labeled 2400 mAh, but it performed quite well. I ran it up to 5 amps before the protection circuit kicked in. A repeat run at 1 amp revealed no change in capacity over the first run at 1 amp.

I still don't know if this is an isolated occurrence or if this is the norm for these cells. Based on the little testing that I have done, I would not recommend these cells in a multi cell application, but they should do well for single cell use.

However, I stop using Li-Ion cells when they drop below 80% of their initial capacity. If these cells were originally 2400 mAh, I would stop using them when their capacity under a 1 amp draw dropped below around 1900 mAh. None of these cells tested out at above 1900 mAh. The one cell that worked came in at just under 1700 mAh or about 71%.

Perhaps they are really 1800 mAh cells with the wrong label on them...

Tom

 

[WildChild]

Tom I didn't expect a much better capacity with the 2 I have. But since they don't heat when I charge them and they seems to work well, I'll keep them. Also, there is a variation with the length of the 2 cells I have. Is there a good variation with the ones you have?

 

[SilverFox]

Here is the comparison data from the 3 cells. Bad 1 and Bad 2 were cells that had bad protection circuits. The protection circuits were removed for this comparison. Good refers to the cell with the good protection circuit. The test load was 1 amp for all three cells.

These cells are labeled 2400 mAh.

Tom

 

[ak645]

Hi Tom,

Heh,I was wondering what happened to that other cell.They must've sent it to you by mistake.This one was from a different batch which may explain the different performance.

At first my results were similar to yours with reduced capacity and severe voltage sag under load.Then things seemed to improve.During my in-light testing,after several charge/discharge cycles,I saw better results..I ran 2 amp ROP/LO bulb for 58 minutes from 4.2 to 3.5 volts.

I wonder if you'd mind running the good battery through a few charge/discharge cycles to see if there's any improvement in it?

Andy

 

[SilverFox]

Hello Andy,

Here is the test results from the cell with the good protection circuit.

When the testing was completed, I ran another 1 amp discharge to see if there was any degradation (or improvement) in the cell. There was none.

Tom

 

[WildChild]

A question about those. After about 4-5 cycles, mines started to drop to around 4.05V-4.06V on the shelf the day after they have been charged. When went out of the charger at around 4.17V-4.18V. Normal behaviour or a sign they are starting to die?

 

[DM51]

They are on their way out. When they can't hold 4.0V (~80% charge) they have had it. You may find they are heating up a bit on the charger, due to increased internal resistance; but one way or another, it doesn't look as if they are going to last you much longer.

5 cycles. What a great record. I'm sorry to say it, but you wasted your money there. Where did you get them?