Ultrafire 18650 drama- Mtbr.com
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  1. #1
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    Ultrafire 18650 drama

    I bought 4 Ultrafire BRC protected 18650 3000mAh batteries from DX recently.

    As arrived they measured 4.0v + - .2v. I put them in the soshine s1-max charger and they charged for about an hour and then turned off. I measured them all at 4.2v-4.26v

    Put them into my home made battery pack in series to drive my diy dual mce light using a hipflex with max output set to 1400ma. ( 2 serial configured mce in parallel )

    Have been testing the light on the bench for thermal mapping of the housing and out on the track ( an hour ride ), all up about 2.5 hours of run time between 350ma-1400ma ( using the power settings on the hipflex )

    All was going well until the last bench test which was 1400ma with a small fan set at 10kh/hr. I started this test with the battery pack measuring 15v. Was measuring the outside temperature of the housing which was slowly rising up to the 25 minute mark. At the 35 minute mark it had dropped back 10 degrees. Was just about to stop the test to try figure out what was happening when the light shut off.

    I measured the battery pack at 10.5v but as I had set the LowV setting on the hipflex to 13v I couldn't understand this. I took the batteries out of the holder and the first 3 measured 3.5v each, the last one measured 14.7mv! Have tried charging the 14.7mv battery but looks like a gonna.

    My predicament is that I have a race this Saturday and there's no way I can get a replacement battery from DX in time ( I live in New Zealand ). Can I mix another type of battery ( eg NIMH ) with the 3 Li-Ion ones in the pack without disaster? 3 * 18650 fully charged = 12.6v which will not be enough to run the light through the hipflex.( I know I would have to make an adaptor for the different length battery but this is quite doable )

  2. #2
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    Pick some up off trademe.

  3. #3
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    I would not mix em with other types of cells. Could the protection circuit have failed on the bad cell?

    One other thing to consider is that the charger may have killed the cell or it's protection circuit. The DX site has a post about one of them burning down somebody's room. I had the SC-S1 and had a similar problem, but stopped it before it could cause damage (smelled like it was burning). Anyways please be careful, the cells can be very dangerous if damaged or shorted.

  4. #4
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    rickh1, this is your mistake. you should buy unprotected cells and use one special 4cell PCB!

  5. #5
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    Almost definately dead protection, you should be able to remove this from the cell and it should / might keep working fine.

  6. #6
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    I think someone mentioned before that the Ultrafire 3000mah batteries were best used in applications < 1000ma. With that said I can't see any reason why they can't work. Looks like one cell's protection died...or....the protection is working and cut off the cell before any further damage could be done to the cell. Stuff happens. As cheap as these things are I'm surprised you didn't buy more with the original order. With the D/X stuff you always buy more than you need...more batteries ...more chargers....unless you really like sitting it out while the new stuff is in transit. In my opinion If I were you I would order 4 x Trustfire (blue ) 2600mah cells plus one of the other Ultrafire 3000mah to complete your previous set.

  7. #7
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    znomit - thanks for the local supply advice
    ck - i'm a novice at electronics so thought the protected option was best for charge / discharge options
    cmd - lesson learnt from dx

    so what charger are people using for their 18650 cells that are reliable & safe?

  8. #8
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    Stick to protected and don't let them over discharge still, they just won't charge again the protection isn't that great.

    I've got 2 of these, in use for 18months and fine!!

    http://www.dealextreme.com/details.dx/sku.13820

  9. #9
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    First thing, the 4.26v fully charged isn't good as 4.2v should be the absolute max for a Li-ion cell so I don't like the sound of your charger(not that I can hear it but you know what I mean )
    I have removed the protection from all my DX cells and use my bFlex for low voltage protection.

    The protection in these cells is pretty [email protected] so it may be what has gone bad.

    This is what to expect under the wrapping.
    Attached Images Attached Images

  10. #10
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    If the protection died, I would strongly suspect the charger (personal bias). Also as yeti said, it is overcharging it also which could put the fire in your Ultrafires. Removing the protection circuit could remove the last safety your cell has before poof time on the charger.

    Regardless of how good the charger is, I would not charge unattended or near anything that could burn. A bucket of sand nearby would be a good idea - if something does go up, remember that it would be a metal fire and Li does not like water - or maybe it likes it too much.

  11. #11
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    Just to point out that I am not a fan of danger and once I have removed the protection I then solder the cells together with the solder tabs that held the PCB, fit a ballance lead and charge with my balance charger.

    Should have pointed that out first 'caus as huffy said these things are dangerous.

  12. #12
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    thanks for the info guys. I'll stick to buying protected cells and maybe a new charger.

  13. #13

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    Quote Originally Posted by Turveyd
    Stick to protected and don't let them over discharge still, they just won't charge again the protection isn't that great.

    I've got 2 of these, in use for 18months and fine!!

    http://www.dealextreme.com/details.dx/sku.13820
    One of the problems with DX (it seems) is that what was a good product 6 months ago might not be anymore as they don't seem to take a great deal of care to make sure they are sourcing genuine stock.

    I am particularly worried about purchasing an 18650 charger for Australia, as some of the chargers on DX seem to go ok with 110V but make the magic smoke appear with 230V, i.e. crappy components inside go poof.

    Can anyone with 220/230 mains power recommend a charger from DX purchased in the last month or so?

    Also, which 18650 cells should I buy? I definitely need protected cells, especially as these will be used by someone else, and I'm not sure he will be as careful as I would be.

    I'm a bit worried by reports which seem to suggest that the protection circuits on the cells in DX don't seem to work.

  14. #14
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    Quote Originally Posted by yetibetty
    First thing, the 4.26v fully charged isn't good as 4.2v should be the absolute max for a Li-ion cell so I don't like the sound of your charger(not that I can hear it but you know what I mean )
    I have removed the protection from all my DX cells and use my bFlex for low voltage protection.

    The protection in these cells is pretty [email protected] so it may be what has gone bad.

    This is what to expect under the wrapping.
    Hang on a minute. Do all 18650 protected cells from DX come with tabs, or is it only specific models? I haven't ever pulled on of my protected cells apart to check.

    Are you then soldering them together to make your own packs? I assume this can be done safely since they are tabbed cells.
    edit: sorry, you answered this bit a post or two later

    Do the non-protected cells from DX come with tabs at all?

  15. #15
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    Salty, they have to have tabs in order to have something to solder the pcb(protection) to
    .
    If you do have a go then do not let the tabs touch the battery body and you will have to re-shrink wrap each cell.
    The tabs are quite small but plenty to solder cells together via a short wire.

    All of the packs I have done are still going great and balance charging is so much better.

    I posted details of my 5 cell pack some time ago in here posts 12 & 46:http://forums.mtbr.com/showthread.php?t=494261

    Good luck...it's dangerous playing with Li-ions, but great when it works.

    EDIT: There won't be tabs on non protected DX cells as they are not required and I use the blue "2500"mah protected cells from DX.

    This is a pic of a 3 cell pack that I made with DX cells and a balance plug.
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    Last edited by yetibetty; 09-11-2009 at 09:28 PM.

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