THE RISE OF THE 18650 LITHIUM CELL



MUCH INFORMATION — THANKS TO:  Tim Brookes  Senior Writer  for   https://www.makeuseof.com/  who in another universe, Australia must have a few alien DNA’s I am festooned with.  He loves science, hates scammers and is into food, my kind of friend.  His website is informative, credible and easy to read.    

Tim is a senior writer for MakeUseOf who lives in Melbourne, Australia. You can also find him at VeganTricks.com where he blogs about food and other things.  You must bookmark his website, it has answers to so many things that befuddle us…



THE 18650 LITHIUM CELL

The 18650 is a rechargeable lithium-ion battery.  Bigger than a AA cell and capable of far greater capacity, they were commercial only at one time.  It was question of time, science and a couple of ingenious add ons that have made this battery more popular because of size and chemistry.  And it has bled out to the consumer and has become very popular.

However, these new lithium cells have not been standardized quite like the rechargeable AA’s you’ll find in the supermarket. It’s called counterfeiting.  You have to make sure you buy the right 18650 battery for the job, they vary greatly and you’ll need to know how to avoid fake batteries.

SIMPLE SPECS

  • 18650 battery is a single cell
  • 18 mm x 65 mm in size  usually… fakes sometimes vary.
  • The name, 18650, refers exclusively to the size of the lithium-ion battery cell
  • The 18650 has become the new gold standard for replaceable and rechargeable batteries
  • They offer the performance of a lithium-ion cell
  • Capacity in the range of 1800mAh to around 3500mAh
  • At an output of 3.7 volts
  • 18650 cells offers the best performance of any consumer-grade rechargeable battery
  • No memory problems
  • But  life cycles estimated at 300 to 500 recharges.  Same rate as your smartphone batter,y, same chemistry


TECHNICAL

  • The 18650 isn’t a standardized cell.  Actually in the last fifty years no real stands aexist in the battery industry.  They’re not all built equally, or with the same dimension or placement of components.
  • The most important trait to consider when looking at 18650 batteries is the continuous discharge rating (CDR), also known as amperage capacity which is usually published but counterfeiting scams fake those too,
  • 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.
  • 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.
  • 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.
  • 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.


HOW TO AVOID FAKE 18650 BATTERIES

  • 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.
  • 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 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.

⚠ WARNING:

Use caution as misusing or mishandling the battery may cause a FIRE or EXPLOSION which may result in personal injury or property damage. The user must have an appropriate understanding of the potential dangers of LITHIUM ION BATTERIES before purchase and usage. No express or implied guarantee of compatibility, suitability, or fitness for any particular purpose or device can be made. This battery is manufactured and sold for the intended use of system integrations with proper protection circuitry or battery packs with a BMS (battery management system) or PCB (circuit board/module). This battery is neither designed nor intended to be used with an E-CIGARETTE, VAPORIZER, or similar device. USAGE OF THIS BATTERY IS AT YOUR OWN RISK!

  • DO NOT USE WITH E-CIGARETTE, VAPORIZER, OR SIMILAR DEVICE
  • DO NOT STORE LOOSE OR IN A POCKET, PURSE, ETC. ALWAYS USE A PROTECTIVE CASE OR BOX FOR STORAGE AND TRANSPORT
  • WHEN NOT IN USE, ALWAYS STORE LITHIUM ION BATTERIES IN THE PROTECTIVE CASE/BOX IN WHICH BATTERIES WERE DELIVERED
  • Misusing or mishandling lithium ion batteries can pose a SERIOUS RISK of personal injury or property damage
  • BATTERIES MAY EXPLODE, BURN, OR CAUSE A FIRE IF MISUSED OR MISHANDLED
  • Usage of batteries is AT YOUR OWN RISK!
  • ONLY use with proper protection circuitry
  • DO NOT short circuit intentionally or unintentionally
  • KEEP AWAY from metal/conductive objects to prevent short circuiting
  • DO NOT use if PVC wrapper or terminal insulator is damaged or torn
  • DO NOT use if battery is damaged in any way
  • DO NOT over-charge or charge above the maximum voltage rating
  • DO NOT over-discharge or exceed the continuous discharge rating
  • DO NOT modify, disassemble, puncture, cut, crush, or incinerate
  • DO NOT expose to liquids or high temperatures
  • DO NOT solder onto battery, spot weld only
  • DO NOT use force to install or install in reverse/backwards
  • ONLY use within manufacturer’s specification
  • KEEP AWAY from pets and children
  • ALWAYS charge in or on a fire-proof surface and never leave batteries charging unattended
  • ONLY use a smart charger designed for this specific type of battery
  • DO NOT mix and match brands and models, old and new, used and unused batteries
  • STOP immediately if while charging/storing/using the battery it emits an unusual smell, feels hot, changes color or shape, or appears abnormal in any way
  • It is your responsibility to determine that your charger or device is functioning properly
  • If exposed to battery electrolyte, flush with water immediately and/or immediately contact a physician or emergency services
  • DO NOT throw away in trash; contact your local jurisdiction for proper recycling or disposal


Sony VTC5A (Datasheet)  Sony VTC5 18650    CDR/Capacity: 35A/2600mAh   Weight: 47.1g (variation of 1.5g)

Sony VTC6 (Datasheet)    Sony VTC6               CDR/Capacity: 15A/3000mAh    Weight: 46.5g average

Samsung 25R 18650                                          CDR/Capacity: 20A/2600mAh     Weight: 43.8g average

Samsung 30Q 18650                                         CDR/Capacity: 15A/3000mAh      Weight: 45.6g average

LG HD2 18650                                                  CDR/Capacity: 25A/2000mAh      Weight: 44g maximum

LG HG2 18650                                                  CDR/Capacity: 20A/3000mAh      Weight: 44-45g


DON’T FORGET A CHARGER FOR 18650 BATTERIES

  • Again it’s a market of genuine versus the knockoffs and fakes.  The origional author  suggested to avoid disappointment, always pick a quality charger. He recommended 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   BUY NOW ON AMAZON
  • 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.
  • You can also buy the Nitecore D4 with a car adapter for charging on the go, with room for four cells to charge simultaneously.
  • 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).
  • 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. You could also opt for one of the other battery retailers who have a reputation for providing genuine, high-quality batteries.
  • 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.