What You Need to Know About the 14500 Lithium Battery

Anyone who’s ever used a battery operated device, is extremely familiar with alkaline batteries. They’re the gold standard when it comes to the majority of electronics which use them. But, in recent years, rechargeable LITHIUM batteries have been gaining in popularity as well. One of these such batteries, is the 14500 lithium.

With the introduction of LED flashlights for example, the 14500 lithium battery has proudly placed itself among its prestigious lithium cousins. As pictured (for comparison) a 14500 lithium cell is identical in shape and size to a standard AA battery. But that’s where the similarities end.

top -14500 bottom – AA Alkaline

Similar, Yet Very Different

  • All standard alkaline batteries are 1.5 volts. Most lithium batteries (incl. the 14500) are 3.7 volts. That’s a major difference right there!
  • Standard 1.5 volt batteries are disposable. The 3.7 volt 14500 cell is rechargeable.
  • For flashlights in particular, the higher voltage provided by a 14500 battery, allows them to be much brighter than if they were using a 1.5v battery.

Check Your Voltage!!

What is absolutely essential, is that the device you’re looking to use a 14500 in, be able to accept a 3.7 volt battery!! The list of devices made to operate on a SINGLE AA (1.5v) battery, which can also accept a 3.7v lithium, is very limited. In fact, of all the gadgets I own that use AA’s, an LED flashlight is the ONLY one that can accept it…and the only one that actually benefits from it.

LED Flashlights

 Let me expand on the whole flashlight thing.

Most flashlights that run on ONE AA cell, can also accept a 14500 lithium battery. On the other hand, flashlights that use TWO AA cells, CANNOT accept 14500 batteries. This is due to the voltage limitation of the light, which typically will have a limit of 4 volts. Therefore, ONE 3.7 volt battery is okay, but TWO of them, at 7.4 volts is too much voltage! It would physically kill the flashlight to feed it that much power! 

The only reason for using a 14500 in a flashlight is for higher lumens. Naturally if the light was made to be able to accept 3.7v, the higher lumens the voltage offers, will be its main selling point. A flashlight that is specifically intended for ONE 1.5v battery, can usually accept a 3.7v as well. In that case, the advertised lumens will be LESS, since it’s INTENDED for 1.5 volts. Make sense?

I recommend reading the manufacturers specifications carefully, which should indicate the working voltage range. Having said that though, single AA lights WILL NOT list voltage limits. The only one that usually will, are the ones that can use both. 

On rare occasions there might be a manufacturers note, warning against the use of higher voltage batteries. The warning will usually advise that if the higher voltage causes the LED to fail, it will void the warranty.

Heat Advisory

Sometimes, using a 14500 battery in a flashlight can cause it to become unusually hot. Caution is advised in that case, even though many flashlights have protective measures at dealing with excessive heat. Try to make sure the device you’re powering can handle voltages over 1.5, or the extra power could cause irreversible damage.

In general, when using Lithium-ion batteries it’s important to know how to handle them safely, and be aware of the possible dangers. This post discusses lithium battery safety.

For purchasing options of 14500 batteries from Banggood.com; click here!


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  1. dummy AA cells (with a wire conductor + and – internally) can be had to allow 14500 to be used in devices that accept 2xAA

    • Yes… I don’t have any AA spacers, but thanks for the info.

    • fully charged 14500 of 4.2 volts are still much higher than 2xAAs of max 3 volts. you’re just lucky that your device accepts the extra 1.2 volts.

      • Thanks for commenting!

        Yes 14500 batteries are excellent alternatives when looking for an extra boost in power. There are many flashlights that can accept them.

      • Fully charged Li-ion batteries can be as high as 4.35v, depending on the charger. Programable chargers can charge to an specified lower voltage, which is good for the longevity of the batteries. Milspec is to charge them to 4.00v, which gives many more cicles for a modest reduction in capacity. The recommended cutoff voltage is 3.00v, in any case. It is safe to discharge to 2.75v with the same caveat of a higher charge voltage.
        Brand new Alkaline batteries can be as high as 1.85v each, or 2×1.85v=3.70v, 3×1.85v=5.55, and can and should be discharged to 0.9v, or 1.8v combined for two and 2.7 for three.
        So it is safest and most compatible to use one Li-ion to replace three Alkalines.

  2. I have an LED flashlight that has a ring at the positive end. It allows some + tip batteries to reach the contact but others do not. WHY are 14500 batteries with “different overall lengths” and “different + tip lengths”. I had to buy 3 times to buy one that would make contact with both ends. Yes all three work if I added an extension of the + tip but one shouldn’t have to. Why is this? Since all are the same 3.7V.

    • It’s an interesting question Mike, and it doesn’t ONLY affect 14500’s. 18650 batteries can also vary in length, and sometimes in thickness as well. With regards to length, it usually varies because of the protection circuit that’s added to it. I’ve experienced this too, and have a few 14500’s that won’t work it certain lights. That CAN be one particular problem when buying single AA/14500 lights. There’s always a chance that some brands of batteries will be too long. The solution is to power them with unprotected 14500’s, which USUALLY fit more easily. Olight (for example) makes great batteries, but their protected 14500’s are typically longer than most.

      So, the unfortunate answer to your question, is simply “because they can be”.

    • That’s what a penny is for.

  3. Can a 14500 1200mAh 3.7V Li-ion battery be used in a Xbox one controller?

    • First of all, there’s no such thing as a 1200mAh 14500. The MAXIMUM capacity is 750mAh. If you HAVE one (or have seen them for sale online) that claims 1200…I’m afraid it’s not the ‘real McCoy’. So. I don’t own an Xbox, but from what I’ve seen, they use two AA’s. Is that the case with yours? And if that’s true…then NO they will NOT accept 14500’s because the voltage will be WAY too high! If you’d like to use rechargeable batteries in it, then you’ll need to get 1.2 volt NiMH Eneloop cells. You can get them off Amazon, and they even have them under their “Basic” label as well.

      Thanks for the question Chad!

      • BR Wilkie,
        I’m not sure since Chads question post date of 3/29/2019 if ‘they started’ making 1200mAh 14500 batteries? But I bought 20 of them yesterday on eBay.

        GARBERIEL 1200mAh 14500 Li-ion 3.7V Rechargeable Battery For Flashlight LOT

        Item specifics:
        Condition: New
        Type: Rechargeable
        Battery Size: 14500
        Battery Size: 14500 Brand: GARBERIEL
        MPN: 1200mAh
        Chemical Composition: Li-Ion

        Thought I’d point that out and hope I didn’t get sold some counterfeited garbage?!

        • Thanks for the question (and the link) Dan, but I’m sorry to say those aren’t legitimate 14500’s! Everything about those batteries screams “knock-off”. You can’t legitimately have capacity much over 850mAh in a 14500. I don’t know if you do or don’t….but this is one reason why everyone who chooses to buy rechargeable batteries, should also own either a multimeter, or a high quality charger…so once your batteries are charged, you’ll have a good idea of their status, when relating to voltage and capacity. If you were able to do a discharge/charge test on those, I think you’ll find them to be lower than what standard 14500’s usually are.

          Standard quality 14500’s cost about $6 EACH! Getting ALL THOSE for $11…is just scary!!

          • Sounded too good to be true! Well if anything, ‘A lesson learned’! Though after reading about rechargeable batteries yesterday and the importance of a good charger, I ended up buying a Nitecore Digicharger D4 and Opus BT-C3100 V2.2 Battery Charger. Both of them have really good reviews and cover a variety of types. Already have a few multimeters.
            When all these things arrive, there will be some checking to do… I’ll let you know the outcome.

            Thank you for the quick reply.

          • Thank you Dan! Excellent choices!! Good luck.

  4. One thing to keep in mind is the loss of voltage when in cold temperatures. Have a “KLARUS 750mAh 14500” which went from full charge to below safe operating voltage when below freezing during the night. so always carry some regular “ALKALINE” batteries for my Headlamp.

  5. Many good small tactical flashlights come with a 186550 or smaller plus insert for 2 or 3 regular 1.5 volt batteries.. The typical 3.7-4 volts you will get out of the lithium under load will be far superior to the 4.5 volts out of the regular batteries.. If your flashlight battery holder wasn’t designed to equal the length of a single lithium cell and are gonna use smaller button lithium in the exact same spaces of the original battery holder.. whether it’s originally 2 cell or 3 cell you just have to modify the holder so the batteries are running in series not increasing the voltage past 3.7-4.2..
    No matter what the case, you’ll get a MUCH brighter light, longer run and simply recharge them instead of throwing them away..

    • Yes that sounds right…although I’d be leery about button size lithiums. And just to clarify, it should read “18650” in your opening comment.
      Thanks for commenting Ken!

  6. I have an LED torch which has a single 3W Cree LED and is powered by one AA battery. Is this size LED capable of being powered by a 14500 lithium rechargable?

    • I would need a bit more information. “3W CREE LED” isn’t very descriptive. The name and model of the flashlight would also be helpful. What’s important, is to know what the voltage capacity of the flashlight is.

  7. The brand is Arlec, but I doubt that will tell you much as it is an electrical component company in Australia, and the torch came with no detailed specifications (sub $10 from a big hardware chain). Since my comment I have used a 3.2V LiFePO4 battery in the torch with no issues. The torch is now about twice the lumens and no overheating issues.

    • That sounds promising! I would say you can certainly TRY a 14500…but carefully! They will work in a lot of different lights, even when manufacturers don’t recommend it. But what often happens, is some of the modes aren’t available, or it may only work on the highest mode. I’ve tried them in lights I wasn’t sure of, and usually only in short bursts. But as it turned out they were fine, but just with less modes.
      Thanks for the information.

  8. Thanks for the reply. The LiFePO4 I am using is a 14500 size. All the torch modes still work. I will try a standard Lithium ion when I get my hands on one. In case you are interested, this is the actual torch. https://www.bunnings.com.au/arlec-mini-3w-led-torch-with-pocket-clip_p0180889
    It is a bargain and I saw some thief on ebay trying to sell them for $41.63.

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