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18650 Battery Buying Guide

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18650 Battery Buying Guide

Consumers have a difficult time keeping up with the ever-changing battery size terms. Most consumers are familiar with the omnipresent A, AA, and AAA battery sizes, but many of the same consumers do not understand the meaning of other battery size terms, such as the 18650. Manufacturers produce the lithium ion 18650 at a size of 18 mm by 65 mm. Consumers may find a "D" at the end of every 18650, which denotes the shape of the battery. Newer 18650s possess a protection circuit that adds additional length to the battery. Labels and packaging also alter the size of 18650s, adding further confusion to the way consumers can use the battery. Despite the inconsistencies, manufacturers are working to implement uniform production standards to mitigate size confusion. In the near future, consumers can expect a uniform manufacturing standard for 18650 batteries.

Origins of the 18650 Battery

Binghamton scientific researcher, M.S. Whittingham discovered the concept of lithium-powered batteries during the late 1970s. He combined lithium and titanium sulfide to charge the first battery. Lithium provided enough power for the battery, but Whittingham became concerned with safety issues, some of which precluded commercial uses for the newly discovered battery. Rachid Yazami, who worked for the French National Center for Scientific Research, published an extensive research paper in 1980 that claimed that lithium batteries had commercial potential, if the use of lithium metal was restricted, and some other form of lithium that contained lithium ions was used in its place. Tinkering with the lithium battery model continued for another decade, until Sony released the first lithium-ion battery in 1991. Sony scientists perfected a battery that integrated lithium cobalt oxide into the battery’s chemical composition. By 1996, the lithium metal problem disappeared, as scientists added lithium iron phosphate to advance lithium battery technology.

Lithium Cells Described

Lithium powered batteries rely on lithium cells to interact in order to produce power. Shaped like very small coins, lithium cells are thin compared to their diameter. The design includes a metal can that is the positive terminal and a cap that is the negative terminal. Lithium manganese dioxide (LiMnO2) forms the chemistry for 18650 batteries. The three volts or more produced by this type of chemistry restricts lithium cell alternatives. Lithium cell shape and size remains consistent in every lithium battery model. The most practical result of using lithium cells is that one cell can replace two alkaline or silver-oxide cells. Manufacturers provide their own part numbers for lithium standardized cells.

Why Consumers Love the 18650

The decades of diligent research and constant tinkering have produced a lithium battery that presents many advantages to consumers. As researchers find additional ways to use the 18650, production of the battery continues to increase. Higher production rates have led to declining costs. Lower costs are just one factor that make the 18650 battery popular among consumers of electronics.

Multiple Uses

One of the major drawbacks of many battery types is the limited number of ways in which consumers can use them. 18650 batteries have many uses and the rapid advancement in technology leads to even more uses for the 18650, especially in wireless communication and entertainment devices, such as digital media streamers. As of early 2012, laptop computers and flashlights represent the fastest growing market for 18650 battery use. The 18650 works with virtually every laptop and flashlight model. Consumers also find the 18650 to be an excellent fit for e-book readers, digital camcorders, and digital cameras.


After cost, consumers may judge a battery by the product’s primary purpose: to provide long-lasting power. Tested against other batteries that can charge similar products, 18650 batteries perform reliably for longer periods. Because of the battery’s longevity, 18650s have become the preferred battery for charging devices that consumers need to use in emergencies, such as flashlights and portable radios. The iron phosphate that MIT researcher Yet-Ming Chiang developed in 2004 has improved the battery’s performance and extended its shelf life.

Leading Manufacturers

Once the 18650 battery became a durable and safe prototype, leading manufacturers such as Sony and Panasonic began developing the lithium-charged battery. Consumers buy from brands that they trust, and both Sony and Panasonic, among other leading battery manufacturers, have given 18650 batteriescredence for everyday use. One of the problems the battery had early in its development was a lack of commercial support from established brands.


Energy density is an important component of battery quality, and the 18650 lithium-charged battery has over twice the energy density of nickel-cadmium batteries. Higher density translates into better-performing electrodes. Higher density also provides consumers with little or no maintenance issues. 18650 batteries have no memory and possess no regular cycling that batteries need to extend their shelf life.

Common Attributes of the 18650 Battery

Although 18650 batteries have varied attributes that depend on both the manufacturer specifications and model type, they possess enough common characteristics to form a list that consumers can use to judge the merit of using the batteries in their electronic devices. Consumers should be sure to understand what their electronic device requires, before they choose a 18650 battery type to power it.

The 18650 battery typically has a power of 3.7 volts and a current of 2600mAh. An overwhelming number of 18650 types are rechargeable. This feature should become the uniform standard moving forward. The cylindrical shape and battery design prevents harmful electrode liquid leaks. Also available to consumers are 18650 batteries that manufacturers package with chargers. The chargers contain and automatic off system that shuts down battery charging when it reaches a limit of 4.2 volts.

Where to Find 18650 Batteries

Once relegated to the shelves of small specialty electronics stores, consumers can now find 18650 batteries in big box retailers and national electronics stores. Many of the larger stores devote an entire section to 18650 batteries, and they merchandise them by placing them near products for which consumers use them most. For consumers who have limited knowledge of 18650 battery applications, the best place to shop for the batteries is smaller electronics stores, where the service staff are likely to be more knowledgeable than the staff at large retailers. Consumers can choose from 18650 battery packages that contain two batteries up to as many as 12 batteries, depending on the manufacturer.

Consumers can also purchase 18650 batteries from the same retailers online. This is the preferred method of shopping for 18650 batteries among consumers who do not have an immediate need for the batteries. Savvy consumers buy 18650 batteries at the leading online auction site, eBay, where they patiently bid on the batteries within a designated time frame.

Buying 18650 Batteries on eBay

Consumers who purchase their 18650 lithium batteries for back ups to a current stock find that eBay is a wonderful place to shop for the batteries. Many eBay sellers offer 18650 batteries that have not been taken out of the original package. This is due to sellers buying the 18650s, and then realizing they were either not the type of battery they needed, or they decided to buy a different 18650 battery type from a different manufacturer. The bids for packaged 18650 batteries fall under the prices that buyers can expect to pay at retail outlets. Stay away from sellers that sell used 18650 batteries. You have no way of knowing how much juice remains in used batteries. Some sellers may claim that they only removed the battery packaging and that the batteries that they want to sell are just like brand new, but this may not be the case.

eBay takes an active approach in promoting its most reputable sellers. Buy your 18650 lithium powered batteries from eBay sellers who have received the Top-Rated Seller designation. This means that these sellers have established a record of offering high-quality products and running legitimate auctions. On every eBay seller’s product page, you may find customer feedback that will provide more information about a seller’s reputation. Make sure to run different searches, including setting your criteria by price and shipping. 18650 lithium-charged batteries are typically a low-priced item on eBay and you may find numerous sellers of the batteries. This means you should search for auctions that run shorter than most other eBay auctions. Since you may not have access to an 18650 battery expert, you must confirm that the type of 18650 battery offered by an eBay seller matches the battery required by the electronic device you want to power. eBay sellers also offer a wide variety of 18650 battery chargers.


What was once considered an outside-the-mainstream technology has now taken over the battery market. After years of tinkering with chemistry and design, manufacturers have created a multi-purpose and reliable 18650 battery. The use of lithium ions has assuaged the safety concerns that plagued the 18650 prototype early in its product history. Consumers find that the numerous benefits of purchasing 18650 batteries include low cost, multiple uses, buying from established manufacturers, and battery longevity. 18650 batteries have become so popular that companies such as Duracell and Energizer are receiving competition from upstart battery manufacturers. The competition can only mean continuing good news for consumers who reap the benefits of even lower prices and higher quality.

The 18650 battery has barely scratched the surface of its usage potential. Since the battery has numerous electronic applications, demand for the battery should only continue to rise as new electronic devices reach the market. Expect the 18650 battery, in some form, to become the standard for the next generation of electronic products.

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