Buying Guides Technology Explained

The Best 18650 Battery and How to Avoid Buying Fakes

Tim Brookes Updated 02-03-2019

The 18650 is a type of rechargeable lithium-ion battery. Lithium-ion batteries have revolutionized portable devices. They’re in everything, from our smartphones and cameras to baby monitors, fitness gadgets, and flashlights.


As battery technology has matured, cells, like the 18650, that were once reserved for device manufacturers, have found their way into consumer hands. However, these new lithium cells have not been standardized quite like the rechargeable AAs you’ll find in the supermarket.

You have to make sure you buy the right 18650 battery for the job, and you’ll need to know how to avoid fake batteries.

What Is an 18650 Battery?

An 18650 battery is a cell that’s 18mm x 65mm in size. The name, 18650, refers exclusively to the size of the lithium-ion battery cell, but there can be minor variations even here. The 18650 has become the new gold standard for replaceable and rechargeable batteries Disposable vs. Rechargeable Batteries: How They Work and Which to Buy How do batteries work? What's the difference between a disposable and a rechargeable one? Why do both still exist? Does it matter which type you use? We answer all of this and more. Read More .

They offer the performance of a lithium-ion cell, a capacity in the range of 1800mAh to around 3500mAh, and an output of 3.7 volts. They’re used in a huge range of devices from laptops to laser pointers, and camera accessories like gimbals and sliders.

18650 battery vs. AA battery
18650 battery (above) size comparison with AA battery (below).
Image Credit: Lead holder/Wikimedia Commons


The 18650 cell offers the best performance of any consumer-grade rechargeable battery. They’re not susceptible to damage from charging before being fully discharged (as was the case with the old nickel cadmium cells), though they’ll degrade at about the same rate as your smartphone battery The 7 Best Battery Life-Stretching Phones Battery life is one of the most critical features in a new phone. Here are the best battery life phones available right now. Read More .

You can’t simply buy a 18650 battery off the shelf by looking at the capacity (measured in milliamp hours or mAh) alone. The right battery depends entirely on what you’re using it for.

Choosing the Right 18650 Battery for the Job

The 18650 isn’t a standardized cell. They’re not all built equally, or with the same task in mind. The most important trait to consider when looking at 18650 batteries is the continuous discharge rating (CDR), also known as amperage capacity.

The CDR is the rate at which current—measured in amps (A)—can be pulled from the battery without it overheating. In order to find out which battery is right for you, you’ll need to match the CDR of the battery with the power draw associated with your device.


Samsung 25R CDR Datasheet

If you pick the wrong battery, the cells will get too hot. Heat will damage the battery, reducing its overall lifespan. Overheating may even cause the cells to explode, leak, or damage your device How a Battery Works and 3 Ways You Can Ruin It The modern battery is featured in so many of our favourite technologies that you could almost be forgiven for not spending time learning about their workings. Read More .

Fortunately there’s a direct relation between CDR (A) and battery capacity (mAh). The higher the capacity, the lower the CDR. That means devices that draw less power can take advantage of higher-capacity cells. Hungrier devices will need to use lower-capacity cells in order to safely draw more current.

At the time of writing (June 2018), the current maximum CDR attainable in an 18650 battery is 38A at 2000mAh. Some bogus manufacturers claim ratings of 40A, or 35A at 3000mAh or greater, but these are not trustworthy ratings. Battery technology evolves constantly, so expect this to change.


Protected vs. Unprotected Batteries

When shopping for 18650 batteries, you will have a choice between protected and unprotected cells. Protected cells, as the name might suggest, have a small electronic circuit integrated into the battery packaging. This is located one end of the battery, and is indistinguishable from the cell itself.

This circuit protects the battery against dangers like excessive charging and discharging, short circuiting, and extreme temperatures. This is designed to protect the devices you use them in, and to prevent damage from explosion or leaking.

Protected 18650 Battery

Many protected batteries also have a valve which disables the cell permanently if the pressure becomes too high inside the cell. This is commonly what happens when batteries swell, at which point they’re more susceptible to igniting.


Unprotected batteries lack this circuitry. They’re cheaper as a result, and also more prone to the problems that such protections are designed to avoid. If you choose an unprotected cell (and many of the best cells are unprotected), you should take extra care when choosing and using your batteries.

Pay special attention to the discharge rating (CDR) to ensure you’re not drawing excessive power from a cell, or it may overheat. You also need to keep the contacts covered, ideally in a plastic case so the batteries don’t short in your bag or pocket. You’ll also need to make sure you don’t leave your batteries in the charger too long.

When in doubt, go the protected route and spend a bit more.

Flat Top vs. Button Top

To really demonstrate how non-standardized the 18650 battery is, there are two slight variations in size: flat top and button top. This relates to the contacts, specifically the positive contact. Button top batteries will protrude slightly, whereas flat top batteries sit perfectly flush.

These extra few millimeters can be the difference between a battery that fits and a battery that doesn’t. If in doubt, look at the existing batteries that came with your device, consult a manual, or contact the manufacturer. For spring-loaded batteries, like flashlights, it shouldn’t make a huge difference.

How to Avoid Fake 18650 Batteries

Like any branded product, you’ve got to beware of the fakes. It’s common for many vendors to buy up cheap cells, rewrap them as name brands, and sell them through Amazon or eBay as genuine items.

Fake LG HG2 18650 Battery
This fake LG HG2 lacks the safety features of a high-quality battery.

Not only is this a waste of your money, it’s potentially dangerous. If you buy a battery for a high-powered device believing it to have an adequately safe CDR, you could injure yourself or damage your device when the battery turns out to have an entirely different rating.

Battery scammers are good at what they do. A genuine battery and a fake are incredibly difficult to tell apart. From the wrapping, to the branding, to the online listings—they look like the real deal. The only way you can tell a fake from a genuine battery is by weight.

Most brands have made the weight of their genuine batteries available somewhere. You should cross-reference any batteries you buy online with the manufacturer’s specification. Even spelling mistakes don’t indicate a fake, as one genuine manufacturer had to point out via a Facebook update.

Dear All , Thanks so much for your attention to our VapCell batteries . Recently we sent one batch of VapCell 18650…

Posted by VapCell on Monday, October 23, 2017

To check a particular cell, try searching the internet for its name followed by “datasheet.” This will list the battery weight, capacity and maximum CDR.

The Best 18650 Batteries

The best batteries are generally produced by Sony, Samsung, LG and Panasonic/Sanyo. That doesn’t mean all other brands are untrustworthy, but these brands provide reliable and trustworthy CDR ratings and enough information for you to spot fakes.

1. Sony VTC5A (Datasheet)

Sony VTC5 18650

CDR/Capacity: 35A/2600mAh

Weight: 47.1g (variation of 1.5g)

Buy: Sony VTC5A on IMRBatteries

2. Sony VTC6 (Datasheet)

Sony VTC6

CDR/Capacity: 15A/3000mAh

Weight: 46.5g average

Buy: Sony VTC6 on IMRBatteries

3. Samsung 25R (Datasheet)

Samsung 25R 18650

CDR/Capacity: 20A/2600mAh

Weight: 43.8g average

Buy: Samsung 25R on Amazon

4. Samsung 30Q (Datasheet)

Samsung 30Q 18650

CDR/Capacity: 15A/3000mAh

Weight: 45.6g average

Buy: Samsung 30Q on Amazon

5. LG HD2

LG HD2 18650

CDR/Capacity: 25A/2000mAh

Weight: 44g maximum

Buy: LG HD2 on IMRBatteries

6. LG HG2 (Datasheet)

LG HG2 18650

CDR/Capacity: 20A/3000mAh

Weight: 44-45g

Buy: LG HG2 on Amazon [No Longer Available]

7. VapCell

Vapcell 2000/38A

CDR/Capacity: 38A/2000mAh

Weight: 43.4 average

Buy: Vapcell 38A/2000mAh on VapCellTech

8. Orbtronic (Datasheet)

Orbtronic 18650 3500/10A

CDR/Capacity: 10A/3500mAh

Weight: 46.5 average

Buy: Orbtronic 10A/3500mAh on Amazon

Don’t Forget a Charger for 18650 Batteries

To avoid disappointment, always pick a quality charger. We’d recommend Nitecore’s i2 Intellicharge charger for 18650 batteries, which will charge two cells at once. You can use it with 18560, AA, and AAA Li-Ion and NiMH rechargeable batteries.

Nitecore i2 Intellicharge Charger for 18650 AAA AA Li-Ion/NiMH Battery Nitecore i2 Intellicharge Charger for 18650 AAA AA Li-Ion/NiMH Battery Buy Now On Amazon $14.85

These chargers detect battery status, then change the voltage and appropriate charge mode accordingly. This should help avoid damage related to overcharging, though you should always take care if using unprotected cells.

Nitecore i2 Battery Charger

You can also buy the Nitecore D4 with a car adapter for charging on the go, with room for four cells to charge simultaneously.

Bundle: Nitecore D4 Charger 4 Slot Smart Universal Charger for Li-ion IMR LiFePO4 26650 18650 18350 16340 RCR123 14500 Ni-MH Ni-Cd AA AAA AAAA C Batteries with EASTSHINE Car Adapter and Battery Case Bundle: Nitecore D4 Charger 4 Slot Smart Universal Charger for Li-ion IMR LiFePO4 26650 18650 18350 16340 RCR123 14500 Ni-MH Ni-Cd AA AAA AAAA C Batteries with EASTSHINE Car Adapter and Battery Case Buy Now On Amazon

You’ll need to exercise similar care when buying a charger as you would when buying your batteries to avoid fakes. For best results, buy directly from manufacturers (or their official outlets).

Which 18650 Batteries Do You Use?

Buying from a reputable dealer, like the manufacturer’s outlets on Amazon or eBay, is a great way to guarantee you’re getting what you’ve paid for.

Don’t forget to filter your Amazon reviews to make sure feedback is genuine How to Spot Fake Reviews on Amazon Don't trust that review or 5-star rating on Amazon to make up your mind about a product. The only way to find a true opinion is to learn how to spot these fakes. Read More . You could also opt for one of the other battery retailers who have a reputation for providing genuine, high-quality batteries.

Related topics: Batteries, Battery Life.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. Tom
    June 24, 2020 at 3:58 pm

    Rarely ever mentioned about 18650 and other types with charging protection circuits is that the circuits can cause RF interference, which in an audio device can generate annoying and unworkable audio noise output.

    The lack of a good connection scheme also is a problem with these types, in many applications you need a pin spot welder (that costs hundreds of dollars used) to join them, springs, pressure, magnets, glue, or solder are often inadequate.

    Given the proliferation of batteries in devices today, there really needs to be better physical standards applied to the whole of all consumer uses up to a general commercial size of battery cell. A consumer grade aluminum fuel cell with ten times the energy also should be added to the list.

  2. Max
    January 2, 2020 at 5:03 pm

    Boards like "BMS Mini/TYPE-C Micro USB" work in protected cells or in unprotected? Protected cells don't need a external charger?

  3. Jenn
    September 5, 2019 at 1:20 pm

    I have a question I'm hoping you can help me with considering it looks like you know a bit about these lithium batteries. I bought a small portable fan from Amazon that comes with rechargeable 18650 batteries (2 x 2200mAh). I'm trying to find the best replacements to order, but this post has me second-guessing whichever ones I find due to them possibly not being genuine. You list the best ones in your post and I wondered which one would be best for a small portable fan that's clearly not pulling a ton of energy from the batteries.
    Thanks for your help!

  4. Jens K Jensen
    March 21, 2019 at 4:18 pm

    The article lists Sony VTC5A as best, but shows picture of Panasonic 18650PF (which is excellent). Which is it (has your site been hacked with wrong picture?)

  5. Vitaly
    November 11, 2018 at 8:04 pm

    An important correction to the article: Even if the battery is heavy enough, it does not mean it is not fake, they could just put a sand into them, which happens a lot judjing from the videos.

  6. Robert
    November 8, 2018 at 9:17 pm

    One really easy thing how to spot most of the fakes: The maximum currenly availiable 18650 capacity is 3400 mah (panasonic). Anything that says it has more capacity is 100% fake (some shops claim to have 3500mah batteries from rare brands, but i never seen them in reality)

  7. Joe
    September 10, 2018 at 5:55 pm

    FYI, the link to the Nitecore D4 links to an 'EASTSHINE' knockoff (though the i2 link is legit), so much for keeping an eye out for fakes. ;)

    June 21, 2018 at 1:11 pm

    Been using these for 5 years, the best in this order are:
    the rest are trash, and the ones listed above have given 18 to 24 months each.

    LOL at the dude who posted "I have to buy all new devices" he's been living in a bubble. Everything out there uses this size now. ..or, get a job!

  9. dragonmouth
    June 20, 2018 at 9:12 pm

    Just what we need, another niche proprietary battery size. It would have been nice if this technology was put into existing battery sizes. To use these batteries, I would have to buy all new devices. It just ain't worth it.