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Thread: Quality issues with UltraFire 18650

  1. #31
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    Default Re: Quality issues with UltraFire 18650

    Quote Originally Posted by WildChild View Post
    When the old ones are charged, they hit around 4.18V and they drop within around 30 minutes to around 4.10V. I have one that has been charged about 3 weeks ago and it now gives 4.03V. Is it a normal drop? Does the protection circuit draw current?

    Thanks
    the quick drop off the charger (4.18-4.10) doesnt prove much, SAY the charger was charging at a good rate, then pulled , the battery was not nessiarily AT the 4.18v rested , but only high when the charge was recentally applied.

    If the charge was the type that completly flattens out the current at the end of charge, and the charge and the battery have ~0 differential, then a drop like that would be noticably bad.

    its hard to explain, but if you used a constant voltage , and waited till there was almost 0 current flow (concidered trickle topping) then a drop in 1/2 hour like that would be abnormal. the fully topped cell would be definatly at 4.18v , not just recentally had power applied to it, like what usually occurs. It is important to note differences in how its charged, because this could cause differences in the data people are referring to, vrses the cell actually taking a dive like that.

    So it rested after charge, and went down to the actual rested voltage it was charged to ~4.10v , if you knew the Current rate that was occuring when it was at 4.18v , you could determine how much of that was just "hot off the charger" voltage.

    so then if we assume it was charged to a rested ~4.10v, 3 weeks to the 4.0 would be the self discharge rate. of course the discharge rate would include any power that the protection curcuit used too.

    one way I (here) will test UNprotected, is let them come down to Rested voltages off the charger , like your 30-60 minutes. then right after that you can assume that its charged TO that point rested. from there the self discharge itself can be determined, any influence from recent charging doesnt change your results.
    So i charge it, test it rested, then test it in a few hours or a day, if the voltage is sinking fast, then the battery is not good. some will sink so fast , you can watch it drop on the meter, those are Really bad :-)

    an unprotected good cell can read so minor a deviation from its RESTED charged voltage as to be off by .01-.03v after 3 weeks. a bad one more like .1-.3 in the same 3 weeks Unprotected, protection can add to the discharge, i dont know how much, or whos protection adds how much.

    that is a long way of saying your 4.18 was not nessisarily a rested voltage, because it would be a lot if it was.

    Your pictures are cool , shows 2 different batteries, cause the vent holes are different. (if they are both bottom protection, which it looks like)
    Last edited by VidPro; 12-03-2007 at 09:10 PM.

  2. #32
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    Default Re: Quality issues with UltraFire 18650

    Quote Originally Posted by VidPro View Post
    so then if we assume it was charged to a rested ~4.10v, 3 weeks to the 4.0 would be the self discharge rate. of course the discharge rate would include any power that the protection curcuit used too.
    I agree that if the charger did not complete the CV phase, the voltage might drop to ~4.1V or some figure like that. This drop should occur within 30 mins, and then settle.

    However there should not then be as serious a drop as a further 0.1V, to 4.0V, within as little as 3 weeks. I would regard that as an abnormally high self-discharge rate, something in the order of 10x what should normally be expected.
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  3. #33
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    Default Re: Quality issues with UltraFire 18650

    yes must be around 10% a month, i dont have the handy dandy chart thing, so i used this http://pdfserv.maxim-ic.com/en/an/AN121.pdf
    If say it was at ~1100, then it would be at ~1000 from the .1V drop.
    with li-ion you can get a fair idea of the capacity from its rested voltages.

    but that is so bad, i doubt my math, not that i wouldnt doubt my math anyway :-)

  4. #34
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    Default Re: Quality issues with UltraFire 18650

    Lol, your math seems OK to me. I think the point is, the drop from 4.2V to 4.1V is reasonable if the CV phase of the charge wasn't completed, but the further 10% drop to 4.0V is NOT reasonable, and indicates a really lousy-quality cell. 10% SD per month is unacceptable. 10% per YEAR would be more in line with what might be expected.
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  5. #35
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    Default Re: Quality issues with UltraFire 18650

    Runtime completed with one old cell: ~57 minutes, 3.3V open voltage right after, before I noticed a drop in output and a drop in flashlight temperature (it was cooler than in the middle of the test...). The cell was charged yesterday.

    [edit]After around 20 minutes, the cell came back to 3.73V.[/edit]

    This is much less than the runtime shown there:
    http://www.candlepowerforums.com/vb/...d.php?t=168873

    I'm doing right now the runtime test with a new UltraFire cell. This one was charged 2 days ago. Reading 4.19V open voltage. I did not measure the open voltage of the old cell before doing the runtime test.
    Last edited by WildChild; 12-04-2007 at 04:08 PM.

  6. #36
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    Default Re: Quality issues with UltraFire 18650

    Runtime on the newer cell:

    Still running and bright. At 2h01, I made a quick pause and measured 3.66V.
    [edit]2h18, 3.60V, still running and bright.[/edit]
    [edit]2h30, 3.44V. I stopped the test! The one I used for the 56 minutes runtime test just finished charging. It came out of the charger at 4.15V.[/edit]
    [last edit]After 20 minutes, the newer one recovered to 3.6V. The old one that has just been charged dropped to 4.12V.[/last edit]


    I charged the old one that was in use. It was at 3.91V. Charged to 4.16V then dropped fast to 4.05V. Older ones are definitly crap! I don't know how many cycles the newer one will last... But yet, they are much better!
    Last edited by WildChild; 12-04-2007 at 06:41 PM.

  7. #37
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    Default Re: Quality issues with UltraFire 18650

    By the way, I use the UltraFire WF-139 Rapid Charger. This is the one AW also sells.

  8. #38
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    Default Re: Quality issues with UltraFire 18650

    Hello Gabriel,

    Looking at the pictures, I believe my test results were with the old cells.

    Tom
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    Most batteries don't die - they are tortured to near death, then murdered...

  9. #39
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    Default Re: Quality issues with UltraFire 18650

    Hmmmmmm,...

    I should read this first and then order Ultrafire Charger with 2x18650 from Ebay of course.

    There is something else I quite don't understand. Protections for this cells is set to low 2.75V and high 4.2V.

    http://cgi.ebay.co.uk/Ultrafire-Charger-Rechargeable-18650-Protected-Battery_W0QQitemZ220178820036QQihZ012QQcategoryZ50 603QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

    Isn't this low a little to low???

    What is the reasonable low discharge voltage limit for this kind of cell?

    Thank you
    Iztok

  10. #40
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    Default Re: Quality issues with UltraFire 18650

    Hello Iztok,

    Under a 2 amp load, 2.75 volts for a low voltage cut off is acceptable. 3.0 volts is better. The idea of the cell protection circuit is to shut down the cell before too much damage has been done to the cell. The circuit that you use the cell in should be responsible for the circuit shut down. If the circuit shut down fails, the cell shut down is a back up safety.

    In actual practice, you should recharge often and never have the "opportunity" to bump into the low voltage shut off.

    Tom
    Behind every Great man there's always a woman rolling her eyes...

    Most batteries don't die - they are tortured to near death, then murdered...

  11. #41
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    Default Re: Quality issues with UltraFire 18650

    Tom

    Thank you for your explanation.

    I am building myself a bike light with 4xSSC P4, MaxFlex and of course some 7.4V Li-Ion input voltage and 700mA on LED's, that requires on input:
    low @ 6V - around 2.1A
    nominal @ 7.4V - around 1.5A
    max @ 8.4V - around 1.3A

    MaxFlex have an option to set low Vin warnings, so I think that 6.5V for low would be O.K.

    Iztok

  12. #42
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    Default Re: Quality issues with UltraFire 18650

    I am sorry to say that I bought a lot of the UltraFire 18650, 17670 and 16340 cells assuming that they would be OK. About 20% of mine go bad after only a few charges (PCB infant mortality?) My voltmeter measures 0.1 or 0 V, and they can't be charged. One read 0 V but would intermittently jump to 4.17 V and light up my LED flashlight. I wonder if it is only a matter of selection. Maybe the other 80% of the UltraFire Li-ion cells will work fine for 500 cycles, and it may be cost-effective to accept a 20% failure rate. I have never had this problem with AW batteries. One reviewer on DX reported that TrustFire Li-ions were much better. Do other members agree? Maybe AW > Trustfire > Ultrafire.

  13. #43
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    Default Re: Quality issues with UltraFire 18650

    I lump all the "fire" brand cells into one big burning pile of you know what.... I wouldn't waste any effort trying to determine which crumby cell is less crumby than the other crumby cells, lol.

    For protected Li-Ion cells, Pila, Wolf-Eyes, and AW are the ones to use.
    For unprotected Li-Ion cells, Panisonic, LG, Sony, Molicel, there's probably other good ones I can't think of ATM.

  14. #44
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    Default Re: Quality issues with UltraFire 18650

    I was so disgusted with the silver shrink wrapped 18650 Ultrafire batteries that I chucked them. No voltage in one and the other was deformed enough that the shrink wrap was slipping of the shoulder of the battery. I've still got 4 Ultra-fire RCR123s that are nearly 3mm longer than any primary cell, preventing me from using them in two cell lights and a few one cells also. I'm not sure what the difference is between the older blue shrink wrapped cells is but I haven't had any problems with the blue 10440s or 14500s. I'm pretty much done with Ultrafire cells now unless I just can't aquire AW or LG cells for some reason.

  15. #45
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    Default Re: Quality issues with UltraFire 18650

    I now had one of the 2 firsts die. After sitting a few weeks charged on the shelf, I checked it and it read 3.40V. The voltage was dropping just checking it with my DMM. I put my DMM in the battery check mode (pulls 100 mA) and voltage dropped to 0V. I retired the 2 bad ones... I'll now use the 2 different replacement cells DX sent me and I'll see if they are better.

  16. #46
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    Default Re: Quality issues with UltraFire 18650

    I own 4 of Ultrafire 18650/2400 which I buy on Ebay, the seller was really fair and quick.

    The first 1-3 charges I was really disappointed, because the running time was really low, but after that, the cells somehow get better and better by each charge, so now I am getting a runtime of 2 hours when I drive 3x SSC P4 with MaxFlex @1A output.

    I build a pack of 2p2s to get 7.4V/4800mAh and I know that the runtime should be a little bigger, but for now I am satisfied, but will probably buy AW's next time.

    I just hope, that this isn't a good before die syndrome,...

    Iztok

  17. #47
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    Default Re: Quality issues with UltraFire 18650

    Quote Originally Posted by WildChild View Post
    New on top, old on bottom:
    Considering I'm old, that's good with me!

  18. #48
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    Default Re: Quality issues with UltraFire 18650

    Quote Originally Posted by EngrPaul View Post
    Considering I'm old, that's good with me!
    I don't recall seeing that particular battery on DX

    Then again, my wife wouldn't let me get one of those batteries anyway

  19. #49
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    Default Re: Quality issues with UltraFire 18650

    Hello EngrPaul,

    Is that the look of the battery of the future...?

    Tom
    Behind every Great man there's always a woman rolling her eyes...

    Most batteries don't die - they are tortured to near death, then murdered...

  20. #50

    Default Re: Quality issues with UltraFire 18650

    +1
    I have purchased six Ultrafire 18650's @ 3100 mah and three of them have failed to accept a charge. My vendor replaced two of these. My third failure happened last week after about a year in service. I am replacing these with the Orbtronic brand.

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