Battery Comparison: 18650 vs. 21700 In Vape Mods

The Long History of the 18650

The rechargeable 18650 lithium ion battery has long been the standard issue power pack for vape mods. The 18650 name is derived from the battery’s dimensions: 18 mm in diameter and 65 mm in length.  Designed in the 1990s, this redoubtable design has found its way into laptops, flashlights, electric bikes and even the original Tesla roadster. You read that correctly, the industry disrupting Tesla electric roadster is powered by the same batteries that you use in your favorite mod. Tesla made a smart move picking the 18650 for their first car. Literally billions of 18650s are manufactured each year and any bugs or subpar manufacturers have long since been identified. Vapor4Life only purchases batteries from reputable manufacturers such as Samsung, LG, Aspire and VRK. Lithium ion batteries are not inherently dangerous, but common sense is required. We recommend that you check out this article on 18650 battery safety. The same safety rules apply to all lithium ion batteries, including the 21700 battery which is the focus of this article.

Enter the 21700

The Tesla roadster’s battery consists of bricks made from 69 18650 batteries. 99 of these bricks are linked to make a sheet and 11 sheets are layered to create a power pack that weighs just under 1,000 lbs. Even the most powerful subohm mod does not require anything quite that elaborate, but there is always a need for more battery capacity. Enter the Lithium Ion 21700 battery. The size-based naming convention remains the same. The 21700 is 21mm in diameter and 70mm in length. The price of the 21700 lithium ion battery has dropped to the point where it is a viable competitor to the popular 18650. So in a world where bigger is not always better, will the 21700 replace the 18650 and become the gold standard for vape mods in the coming years?

The Case for the 21700

After years of reliable service, why do vapers need a new battery? A case can be made that the form and function of 18650 powered mods is nearing perfection. Ergonomically functional and aesthetically gorgeous, there is an 18650 mod to fit any sized human hand. From slender one battery tubes to three battery fog machines, the 18650 has proven itself quite adaptable. Milliamp-hours (mAh) is the unit of measure for battery life and the 21700 has a big edge on the 18650. A 21700 battery manufactured by a reputable manufacturer will provide in the neighborhood of 4000  mAh. This may not sound like a revolutionary advancement over the 18650’s 3000 mAh, but a third more battery life makes a big difference. If you cannot make it through the day without a battery swap, the extra oomph of the 21700 may save you the hassle of carrying a spare battery.  Subohm vapers using e-juice guzzling, low resistance mods are the obvious beneficiaries of the larger 21700 battery. There are obvious advantage on a mod using more than one battery. Two 21700 batteries provide nearly as much life as a three 18650s. The 21700 is not really more expensive when viewed in these terms. They provide a third more battery life and cost about one-third more. This is not too surprising. The lithium ion technology is the same. The difference is the size. Vapers who use single battery box and tube mods benefit from a bigger battery. It is a bit bulkier but can be still be incorporated into streamlined designs.

21700 Compatibility

Unless you are using a mod with a built in lithium polymer battery, like the Voopoo Mojo, chances are that much of your kit runs on 18650s. The good news is that even if the 21700 supplants the 18650 in future mods, availability should not be impacted. The 18650 is not going away any time soon. It is quite prevalent in laptops, and the extra millimeters really count in that application. The current industry trend is to make mods that are compatible with both 18650 and 21700 batteries. This is the best of both worlds. You don’t need to start over from scratch with your power supply and can gradually transition to the superior battery life of the 21700. The Aspire Dynamo is compatible with 18650, 21700 and 20700 batteries. The Smok Mag Grip also runs on 18650 and 21700 batteries. As for charging your 21700, the Nitecore Intellicharger is capable of juicing up both sizes of lithium ion battery.

Do You Need 21700 Batteries?

How you vape will determine how much benefit you derive from the larger 21700 battery. If you are an early adopter of new technology, then it makes sense to try out a mod that relies on the larger battery. If you are chasing giant, delicious clouds all day, burning through both e-juice and batteries, you can benefit from extended battery life. If your vaping is done on lower power settings, using higher resistance coils and nic levels, the 18650 battery is probably fine for your purposes. Mech mod users can also benefit from the larger battery. Not only do you get more life, but 21700 batteries often have a higher max continuous discharge rate, although this varies by manufacturer. If you are happy with your current device, rest assured that the 18650 is not going away. But don’t be surprised to see more mods hitting the market that are compatible with 18650 and 21700 lithium ion batteries. Below is an infographic that summarizes the key advantages of the 18650 and 21700 lithium ion batteries.