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Can I use 579 protected ++unprotected together?

  • nedamdam Friday, August 17, 2012 5:22 AM Reply
    Ordered 2 of them (5790) one came broken, on discharge it was just blinking, well was blinking after a charge... so maybe the charger killed it. However as I removed the protection stuffs, it started working. Using it in the http://dx.com/p/112817 where I put it in the front and in the back the one with the protection. The front unprotected one was always cool, but the protected one heated up under the cap pretty decent.

    Questions is if I can use them in combination, protected/unprotected or something could happen?

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  • sheepish Top 10 Forum Poster Friday, August 17, 2012 6:01 AM Reply
    something could happen?

    In a word, yes.

    If you use them in series and the unprotected one goes flat first the other will reverse charge it, which is a good way to make it release its magic smoke. It's normally called "vents with flames" and the venting can be explosive. The magic smoke is toxic too.

    What do you mean it was blinking? Do you mean the light on the charger was blinking?
    Remembering 30 years.
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  • nedamdam Friday, August 17, 2012 6:20 AM Reply
    No, the Flashlight was blinking, or any other flashlight I tried, when connected to this battery, it just blinked and dimmed itself. Upon removing the protection, everything got operational.
    Charger was fine I guess. Its the OEM cheapest one though.
    I guess you will tell me not to use it then ;) . So not sure I could send it back or how you actually do this with dx. But the price and time of sending it back, would be more effort as just to get another pair.

    Now I am looking into more expensive ones but they have different mAh. Can I combine those? LIke 2500 with 2400 etc?
    The flashlight http://dx.com/p/112817 I bought them for will use 3 of them. So I guess the working blue 2500 one and 2 either this same kind, or another .

    Can you suggest me some batteries/chargers ? :) Thanks

    ALSO THANKS SOO MUCH FOR AN ANSWER MAN!!! Also so fast :) Kinda made my day.
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  • sheepish Top 10 Forum Poster Friday, August 17, 2012 6:47 AM Reply
    Definitely sounds like a faulty protection circuit. I wondered just a few days ago how reliable they are. The cell might still be fine, but I would recommend only using it in a single cell torch. When the LED goes dim you know it's time to recharge it - not a problem.

    There's quite a variety of capacities even with batteries that are supposed to be the same. For example, see my graph in http://club.dx.com/forums/forums.dx/threadid.1042763?page=4#1074759 of six of supposedly the same cell. So even if you combine the same brand and model of batteries they may not be very close. It's OK to combine them if they are protected.

    I think everyone has their own priorities when buying batteries. I've personally got tired of reasonably inexpensive cells that are supposed to be good but change from batch to batch. The next time I buy (which might not be for a while) I'll get Sanyo cells. I believe they make the best batteries in the world, and importantly, they hold a higher voltage under load than most other brands do. For a charger, I just use sku.13820 and am waiting for DX to get a particular 4 channel charger.

    I think all the American battery nerds are in bed now, but I'm sure they would answer quickly if they were awake.
    Remembering 30 years.
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  • nedamdam Friday, August 17, 2012 7:38 AM Reply
    Well I have the same charger, and it actually got green on the cell without the charge protection. So at-least no overcharge.
    But the discharge and charge from the protected one still concerns me.

    Will buy these I guess then :) http://dx.com/p/trustfire-protected-18650-3-7v-true-2400mah-rechargeable-lithium-batteries-2-pack-20392?item=2

    Btw is here some thanks button in this forum so I can express my thanks to you ? :).

    Again thanks for the help
    Posts(7) | Reviews | Tip post

  • jpmaverick Friday, August 17, 2012 8:54 AM Reply
    The "Tip post" is some sort of official "thank you" button, and you can choose how many DX points you want to tip
    BTW those were really good batteries, but you should read this now: http://club.dx.com/forums/forums.dx/threadid.1042763?
    Fortune and glory, kid. Fortune and glory
    Posts(925) | Reviews | Tip post(1)

  • nedamdam Friday, August 17, 2012 9:55 AM Reply
    Well which one you would suggest?
    Also I will need 3-4 of them. The second one just got bad too and I had to remove the protection as well :/.
    Dimmed, die, nothing, and it was not hot, run for like 20 seconds, let it cool, again trying, different combos, different device, nothing. Kinda think that the plate is too soft and the spring is actually pressing too much into it and "connects" or "disconnects" what should not be connected or disconnected.

    Also thanks for help ;)

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  • jpmaverick Friday, August 17, 2012 1:04 PM Reply
    U´r welcome!
    Sku.120476 has good reviews, so if I were you I´d go for it
    I have many "old" sku.20392 and they are really good, but now... can´t be sure which batch you´ll get
    Anyway, I keep buying sku.5790 for resell... I should start checking them carefully
    Fortune and glory, kid. Fortune and glory
    Posts(925) | Reviews | Tip post(1)

  • nedamdam Friday, August 17, 2012 1:22 PM Reply
    Well in my case it could have been the flashlight or the charger killing the protection I would say. The spring of the flashlight and/or charger actually pressed the - plate with the protection a bit inside, I guess thats what could have cause the malfunction. Or something else. I mean I read no bad reviews about them. Maybe one or two like mine.

    Anyway thanks for the tips. When my paypal related account gets recharged I will go on a buying spree. As a friend of mine said. dx is like a toystore for men :D
    Posts(7) | Reviews | Tip post

  • sheepish Top 10 Forum Poster Friday, August 17, 2012 3:54 PM Reply
    Thank you for the tip.

    My graph for sku.120476 was removed - I don't know why. http://club.dx.com/forums/Forums.dx/threadid.1183509. I should repost it. The capacity was good but the voltage under load was poor, even worse than the latest batch of sku.20392 I tested.

    dx is like a toystore for men

    Yes, although I'm not sure if that's good or bad. Watch your wallet!
    Remembering 30 years.
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