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Thread: How Safe are Rechargeable 18650 or RCR123?

  1. #1

    Default How Safe are Rechargeable 18650 or RCR123?

    Now this one has me baffled... Every rechargeable device I can think of has lithium batteries. My laptop, cell phone. cordless drill, and the list goes on. These are fine to keep in the house or in a bag, and recharge unattended over and over again.

    So why are flashlights so dangerous to charge that you need a fireproof container and watch them the whole time? (Let's just say the 2 common batteries RCR123 and 18650)

    I ask this because I have not gone the rechargeable rout yet. The dangers just don't seem worth it. Am I wrong? With AA batteries I would never even think of buying a Duracell... NiMh all the way. They're always on the charger.

    I look forward to your replies!

  2. #2
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    Hello Curly,

    Welcome to CPF.

    If your flashlight is designed to use Li-Ion cells, incorporates a proper low voltage cut off and maximum current draw circuits, comes with a dedicated charger that is designed as part of the package and is designed to charge at the proper rate, keep the cells from overcharging, and incorporates a balancing circuit to keep the cells balanced, or a counter to limit the number of charge/discharge cycles, I don't see any reason to be worried about it at all...

    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...

  3. #3

    Default Re: How Safe are Rechargeable 18650 or RCR123?

    Oops... maybe I need to clarify. I have a Romisen RC-F4 and G4. They both use 2 CR123 or can fit the 18650. (I know the G4 can anyway).

    I guess I didn't word the question properly since I am referring to rechargeable batteries to be 'used' in a flashlight.

    So, I really want to use rechargeables, however I am concerned about the safety of them. I'm in my mid-40s and have used rechargable batteries for a long time. They are so common place in everyday electronics that I never once gave safety a second thought.

    For discussion sake: I buy Tenergy 'protected' (they sound safer) 18650 cells and an Ultrafire charger with 12v cord (it has to work at camp).

    Is a setup like that pretty much the same safety as charging Eneloop or other NiMh batteries?

    Thanks for your replies

  4. #4
    Flashaholic* LEDninja's Avatar
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    I think a single 18650 is safer than 2xCR123A because you do not have the danger of a good CR123A trying to reverse charge a dead CR123A.
    If you use protected batteries you have additional protection against over current, over charge and over discharge.
    As you are using a dedicated charger the charging current and end point should be taken care of automatically. Do take the batteries out of the charger as soon as you notice the light turns green.

  5. #5
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    Hello Curly,

    Perhaps I also need to clarify, or you need to take another look at my post...

    When a laptop or cell phone or other electronics product manufacturer offers a rechargeable Li-Ion battery in their product, there is research, development, and testing done to make sure it is safe to use, and will work fine in their product. They take the time to address the "What if" questions and engineer ways to deal with them.

    When you take batteries from a laptop and use them in your flashlight, you have to address the "What if" questions and find your own ways to deal with them. A fireproof container and attending to the charge, we have found, work very well.

    When used properly, Li-Ion cells work great. The danger comes when you don't use them properly, either through abuse or a lack of knowledge of what is involved with using them. Li-Ion cells have a lot of energy stored in a small area, so the effects of something going wrong are greater than when something goes wrong with a NiCd or NiMh battery.

    Safety and danger are the reasons you are unable, in the US, to run down to the local hardware store and buy single Li-Ion cells.

    Let's look at this a little closer...

    Unless the flashlight is designed around using Li-Ion cells, we are pulling a cell from one service and using it in another. Some of us do a lot of testing to see if we think there are any problems, but we find that there is a lack of engineering data on many brands of cells, and little published test data.

    A Li-Ion cell, while rapidly venting with flame, can see temperatures exceeding 1000 F. This is something we all want to avoid. I am sure you are aware of the laptop battery issues and recalls. We have also heard a few reports of cell phone battery issues. So far, the power tool batteries seem to be "issue" free, although those in heavy use have moved to a safer chemistry.

    Now you may think this is stretching the example a little far... but that has never stopped me before.

    Will a laptop computer run from several cell phone batteries hooked up together? Yes. Is it safe? Probably not, but I think we need more testing to make an educated guess...

    Protection circuits on cells are supposed to be a secondary safety. Your circuit design is supposed to control the cell within its safe parameters. If your main circuit fails, the protection circuit kicks in avoiding the rapid vent with flame incident. If your flashlight and charger rely on the cells protection circuit, you have lost a layer of safety. Will it still work? Yes. Is it safe? You have to decide that.

    The picture I keep in mind is that of a road flare. After the initial rapid venting, a Li-Ion cell will burn in a fashion similar to that of a road flare. If you don't mind lighting a road flare, setting it on your dining room table and then going to bed, you should have no problems charging Li-Ion cells unattended.

    I use Li-Ion cells all the time. I don't know about your particular lights, but I use them in lights that are not specifically designed for use with Li-Ion cells. I also have a laptop and a cell phone and power tools that use Li-Ion cells. I invest in good quality chargers, have a charging area that may not be flame proof, but is flame resistant, and attend to the charging. I test my cells to make sure I am using them safely, and periodically check them for their state of health. I almost never charge Li-Ion cells or battery packs overnight, unless it is outside of my living area.

    I donít think you need to become paranoid about using Li-Ion cells, but you do need to understand the safety issues involved. If you have a family, they need to also understand the safety issues and have a plan of what to do if something goes wrong.

    By all means proceed with your venture into using Li-Ion cells, but do so with caution and understanding, and take a moment to consider safety.

    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...

  6. #6

    Default Re: How Safe are Rechargeable 18650 or RCR123?

    I'm learning a lot here....

    SilverFox, when you say we are taking a battery away from one purpose and using it for another, what do you mean? A 'AA' battery is just made to use in something that takes a 'AA'. They are not manufactured for one specific purpose. So buying a 18650 battery isn't that the same thing? It's not like I'm taking a laptop apart for the battery, but I'm buying the battery generically like any other.

    Your responses have been very enlightening!

    Do people actually watch their batteries recharge every time? C'mon... seriously. You see, realistically I am not going to watch a battery charge. I'm simply too busy. I would think that chargers are made to detect a full charge and turn off.

    So, what you're saying is that I can't put the 18650s in the charger in the morning, go hiking, 4 wheeling, kayaking or whatever all day and just leave them alone until I need them that night?

    I wonder if the additional overhead is worth the effort. Tossing a whole bunch of primary batteries doesn't thrill me, yet it may be better than a 1000* flair in my camper.

    Out of curiosity...what is battery abuse? Honestly...

  7. #7
    Flashaholic* LEDninja's Avatar
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    No. Do you watch a kettle boil?
    When I 1st got my Ultrafire 10440 (AAA size) 14500 (AA size) charger I check on it every 15 minutes. The batteries charged up in ~2 hours. Now I check it after 2 hours and any convenient opportunity after that.
    BTW Li-ons do not have memory so you can charge anytime convenient. Say you have a battery/torch runtime of 2 hours and the battery charges in 2 hours. If you only used your torch for 1 hour you can charge if convenient (and since the battery is 1/2 charged will only take 1 hour)
    Quote Originally Posted by Curly View Post
    Do people actually watch their batteries recharge every time?
    Electronic relays are very good at clamping voltage but a trickle of current leaks through. When a manufacturer of PLCs changed from mechanical dry contact relays to solid state ones all my neon pilot lights stayed on whether the output was on or off. Measured 0V but there is enough leakage to turn the lights on. This tiny trickle would eventually overcharge a battery.
    Quote Originally Posted by Curly View Post
    I would think that chargers are made to detect a full charge and turn off.
    It is best to pick a time when you are close by during the charge. Breakfast, lunch, dinner, doing the laundry.
    Quote Originally Posted by Curly View Post
    So, what you're saying is that I can't put the 18650s in the charger in the morning, go hiking, 4 wheeling, kayaking or whatever all day and just leave them alone until I need them that night?
    This a toughie.
    1) Do not dispose of in fire. All batteries.
    2) In multi battery setups when the light dims one of the batteries is probably dead. Continuing to run means the batteries still good try to charge the dead one cause venting. Swap the batteries at this point. Or try to keep your batteries balanced so they both die at the same time.
    http://flashlightreviews.com/features/123burst.htm
    This is not limited to lithiums. There are at least 2 cases where Fenix L2Ds with AA batteries vented.
    http://www.candlepowerforums.com/vb/...d.php?t=119536
    http://www.candlepowerforums.com/vb/...d.php?t=107585
    3) Use the proper charger. 3.6V Li-ons, 3V Li-ons, and 3V LiFePO4 need different types of chargers. Use the proper one.
    4) Make sure the battery & torch is used within it's specs.
    The Fenix P1D/P2D torches are designed for 3V primary CR123As. Very expensive locally. 3.6V Li-ons won't work (lose low mode). I almost bought some Tenergy 3V LiFePO4 until I saw the 550 mA max current rating. As I expect the P1D/P2D to pull ~700 mA on turbo I ended up buying a L1T instead.
    That is all I can think of on the spur of the moment. There is probably more.
    Quote Originally Posted by Curly View Post
    Out of curiosity...what is battery abuse? Honestly...
    http://flashlightreviews.com/features/rechwarn.htm

  8. #8
    Flashaholic Dr Jekell's Avatar
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    They are safe as long as you follow their instructions & have a VERY health dose of respect for them.

    1) Get a quality, proven charger that is right for your batteries (type, voltage etc)

    2) Buy the best quality batteries you can afford (AW's RCR123's are well respected)

    3) Follow the instructions for your charger unless told specifically by the battery Mfg.

    4) Protected Batteries are safer for beginners than unprotected.

    5) When something doesn't seem/look/feel/smell right replace the battery & safely dispose of the old one (better safe than sorry)

    6) When starting out use a light that is designed for RCR123's eg Novatac's

    7) When charging batteries check on them every so often (you don't need to sit there watching them, perhaps have the charger sitting plugged into a power point near your computer while browsing CPF) If they feel hot or otherwise not as they should be then unplug the charger immediately and refer to line 5.

    There is more but this should cover most of your worries.

  9. #9

    Default Re: How Safe are Rechargeable 18650 or RCR123?

    I have a Romisen RC-G4 from DX.

    Got Ultrafire charger and Tenergy protected 18650 from Battery Junction. I figured they know their stuff and the batteries/charger combo was tested to perform well together.

    As it stands the battery won't fit into the flashlight... They are like 19mm wide (according to my caliper) and the tube is 18. The batteries don't have a pointy thing on top either so I don't they would work anyway.

    At this point I'm back to primaries (which I also get from Bat. Jct. too.)

    Anyway, I have an Ultrafire G8 on the way. Maybe the battery will fit inside that one. The flashlights would only be used now and then anyway, so I now wonder if the 18650 thing is really worth it.

    Don't get me wrong, I have respect for things that deserve it. If I wasn't interested I wouldn't have posed this thread for a real experienced answer. I could certainly deal with charging them at dinner or lunch and such too.

    So now I am back to "undecided"...

  10. #10
    *Flashaholic* mdocod's Avatar
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    Something I have been meaning to do but haven't: A simple way to make a cheap charger much safer:

    Put a crank style timer on it. Build up an apraratus to allow you to select a desired charge time, that will kick off. So if you are charging some little RCR123s and just need like 1-2 hours on the charger, you just set it to 2 hours and forget it, it clicks off within plenty of time to prevent any dangerous overcharging, with some experience you would get to a point that you understand how long it will take (give or take) to top up cells.

  11. #11
    Flashaholic* LEDninja's Avatar
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    Quote Originally Posted by Curly View Post
    The batteries don't have a pointy thing on top either so I don't they would work anyway.
    My 14500 don't have a pointy thing on top either but works with my Fenix L1T v2.0, Lucidus XR-1 and Minimak 14500. I have to be very careful to check the + and - so the battery gets inserted in the torches and charger correctly.

  12. #12

    Default Re: How Safe are Rechargeable 18650 or RCR123?

    For years I raced RC cars. The fancy flat track NASCAR looking type. They use huge current so battery conditioning etc. is very important to the pack lasting for the duration of the race with power left over to win.

    I had all the gizmos. (still do actually) Constant current LCD charger, battery conditioning station, cell matching machine, and such. I charged and my careful monitoring was able to determine capacity, peak voltage, and how to top them off just before the race began. Mind you, I am track side and stuck there for the duration of the race. Winning was important so all the electronic gadgets were tools to that end.

    Even that high tech constant current charger (which I ran from a 50 amp DC power supply) had peak detection and shut down at the appropriate charge level. It has an override for that last minute 'peak' top off.

    So that leads me to the notion that an Ultrafire (WF139 I think - the dark gray one with 12 cord) 18560 charger is "cheap" and may not be the answer for safely charging these cells. I have looked high and low for a "good" charger and the general consensus is that the Ultrafire does the job. It would seem to me if better chargers were available, someone like Battery Junction would sell them. On that note, DX sells chargers that even I think are cheap, yet the reviews are quite positive.

    Sure, I suppose I could get out my 50 amp power supply, hook my outstanding constant current charger to one of these 18650s and pump it a flat 8 amp charge rate until it tops off, but I don't know Lithium batteries. Not to mention that power supply weighs like 75 pounds...)

    So far I have come to this conclusion:

    1. Lithium rechargeables are not user friendly.
    2. All the popular chargers are cheap and marginally adequate.
    Last edited by Curly; 03-27-2008 at 06:27 AM.

  13. #13
    Flashaholic* LEDninja's Avatar
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    I knew I forgot something.

    Do NOT charge li-ons at greater than 1C.

    For a 18650 that is ~2A.

    An 8 amp charge is a NO-NO.

  14. #14

    Default Re: How Safe are Rechargeable 18650 or RCR123?

    Just kidding about the 8 amp charge anyway... )

    Do people keep flashlights with rechargeable 18650 battery in the glove box in case it's needed some day? I think that is a scenario best suited for primaries.

    Thank you everyone for all this important information. It's been helpful.

    At this point I am still pondering the 18650 vs. primary CR123 subject.

    Because the Tenergy protected cells I bought are bigger than 18mm they won't fit anyway. So I guess those are out of the question anyway.

  15. #15
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    Default Re: How Safe are Rechargeable 18650 or RCR123?

    I have a couple of suggestions for you...

    1. Don't give up yet. Send your specific questions directly by PM to either mdocod or SilverFox. If they can't answer them, no one here can.

    2. The Ultrafire 139 charger is successfully used by many CPFer's. It is also sold by AW along with his excellent batteries. If used properly, it should be fine.

    3. I think that Eric's suggestion about using a simple timer to terminate the charge after a specific amount is time is excellent.

    4. If you haven't already, check out this thread. It should answer many of your questions.

    Best of luck!
    Last edited by roymail; 03-28-2008 at 10:42 AM.
    Don't sweat the small stuff...

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