The story behind 18650 batteries

||The story behind 18650 batteries

The story behind 18650 batteries

Did you know there are several different varieties of Lithium ion batteries? For example, Lithium-Manganese Oxide, Lithium-Nickel Manganese Cobalt Oxide, Lithium-Iron Phosphate, Lithium-Titanate, and Lithium-Cobalt Oxide. These batteries help power a wide variety of products from cell phones to Hybrid Vehicles. Crazy right? Not only that, but there are rechargeable and non-rechargeable versions. Lithium-ion batteries were first invented by an Exxon chemist called M. Stanley Whittingham in the 1970s. Which, if you think about it, lithium ion batteries are still relatively new and evolving each year. In the midst of my online search, I learned that lithium batteries are not rechargeable, but lithium-ion (Li-ion) batteries are rechargeable. Can you over charge a lithium battery? No, you cannot because they are not rechargeable. They simply cannot be recharged. Can you overcharge a lithium ion (Li-ion) battery? Yes! I do not know if you guys remember, but a few years back in 2016, there was a period of time when Samsung Galaxy Note7 phones were exploding! They were exploding because of a defect in the phones tied to the lithium ion batteries. Needless to say, that has caused much safer batteries to be produced.

Have you heard of 18650 batteries? 18650 batteries are lithium-ion batteries. They get their name from their size: 18mm by 65mm. These batteries not only used in flashlights, but also in: power tools, electric vehicles, cameras, laptops, and more! A High Drain battery basically means the battery gives out a larger amount of current than regular batteries. 18650 batteries can have anywhere from 300 to 500 charging cycles, which is insane! It usually takes about 3 hours to charge a 18650 lithium-ion battery fully. You know how back in the “old days,” we were taught to let a rechargeable battery go completely dead before -recharging it? Well, that is definitely not the case anymore. I would suggest always keeping your 18650 lithium ion batteries charged over 3.5 volts to maximize your usage. The higher the voltage, the longer your 18650 lithium ion battery will last. Good to know, right? If you have spare 18650 batteries that do not get a lot of regular use, I would suggest charging them at least once every three months. Having fully charged back up batteries is always a good thing.

Now let’s talk milliamp levels. Milliamp is a measurement used for electric current output. The higher the milliamps, the longer the runtime. Say you have one ARB-L18-2600 mAh 18650 battery and one ARB-L18-3500 mAh 18650 battery. They will both give you the same amount of power; however, the 3500 will run a bit longer. The exact runtime length depends on the product you are using your battery in. Some 18650 batteries are also protected. These batteries are created to include overcharge protection and over discharge protection. So, these are literally smart batteries. They have a tiny protection board installed inside them. Crazy! The little circuit board also helps protect against overheating. That is a great thing because no one wants their battery to explode or melt! You really want to pay attention to the specifications when purchasing a 18650 battery.

How long does it take to charge a 18650 battery?
The amount of time that a battery takes to charge can vary depending on the brand of battery and the capacity of the battery. The capacity of a 18650 battery is determined by something called the milliamp level, which can be abbreviated as mAh. The milliamp level of 18650 batteries typically ranges from around 2300 mAh to a maximum of 3600 mAh. Since a higher milliamp level indicates a higher capacity and longer run time, this also means that a 3500 mAh 18650 battery will take longer to charge than a 2300 mAh battery. The difference in charge time will not be extremely large, but it may be noticeable. For example, a 2600 mAh 18650 battery may take an estimated 4 hours to charge while a 3500 mAh battery may take a bit longer, around 5-6 hours. These charging times are strictly estimates and can vary depending on the brand of battery and the brand of charger that you are using, not to mention the output of the power source. A charger plugged into an AC adapter on the wall will take less time to charge a battery than a charger that is plugged into a USB port on a laptop or desktop computer. Because 18650 batteries have somewhat longer charging times, we recommend that you keep at least one spare 18650 battery charged and ready to go, unless you are able to consistently -recharge your battery overnight or between each use. If you find that your battery has died, it will take some time to get your flashlight back up and running, and it is never good to be left in the dark!


Fenix offers 18650 batteries that are designed for use in Fenix flashlights. These 18650 batteries offer a 1-year warranty against manufacturer defects, which means that if the battery dies for any reason other than misuse, it will be replaced for free.

How long do 18650 batteries last?
This is kind of a complicated question because the amount of time that a 18650 battery can last is dependent on a lot of factors. The amount of time they are used, how often they are recharged, and their general care is all important factors that play into the longevity of your 18650 battery.

The thing that causes a 18650 to die is basic use, the act of charging and discharging the battery. The longevity of an individual battery primarily depends on these two components. As such, the amount of time per-use that the battery is having its energy drawn is, of course, to be considered. If you are a police officer or security guard on the night shift and you use a flashlight for most of the night, or if you are a home/pest inspector who uses it frequently throughout the day to look around dark attics or crawl spaces, you will be using more of a percentage of your battery and therefore charging it more frequently than a person who just uses a light for a few minutes a day to take their dog outside or just has one on hand for emergency use.

This leads into the second and most important aspect that determines your battery’s lifespan: The number of times it is charged. When a battery is charged it moves negatively charged ions from one side of the cell, the cathode, to another side, the anode. It is discharging the battery does the opposite. As time goes on, the cathode is damaged slowly causing even the highest-rated lithium battery to lose 20% of its capacity after being charged around 1000 times. Basically, every time that you plug your battery in to charge, you are reducing its maximum capacity by a little bit. The best practice for getting the maximum life from your battery is to use it until it is at about 50% and then recharge it. Then it is recommended that you not keep it plugged in or connected to the charger once it is full. Another thing to remember is that rechargeable batteries, including 18650 batteries, slowly will drain on their own over time. This is simply the nature of the chemical makeup of rechargeable batteries.

This means a few things. One, you do not want to leave the battery plugged in and charging all the time. If you remember that moving those ions from the cathode to the anode causes degradation, you will understand that if you have it constantly plugged in, the battery is going to be constantly moving ions from the cathode as soon as they return there from the anode. The second is that you must make sure to “top off” your battery periodically even when it has not been used. The reason for this is explained in a moment below. Finally, you should never purposefully run your battery until it dies. Causing a 18650 battery to drop to completely dead risks it entering a state called a “deep discharge” which is a point at which there is such a small amount of energy in the battery that its protection circuits will not allow any energy to be added to the battery. This renders your battery permanently dead. This is the same reason that you should make sure to top off your batteries periodically even when they are not used. If the drain on their own to the point of deep discharge, they will be just as useless as if you were to use and drain them fully in a flashlight or other device.

Time for a 18650 cell is typically about 4 hours but can vary with different voltage and amperage of the charger you’re using. Leaving batteries in a charger for extended periods of time can be detrimental to the batteries causing a loss in capacity and charge cycles and can be harmful to the cell if fully discharged. If you will be storing them for a while, then you would want to charge them all the way up and check them every month or so to make sure they don’t get too low as they sometimes cannot recover if the voltage is drained too low. In batteries, the milliamp hours are used to determine how much power a battery will provide for one hour, so let’s say your device requires 1,500 Miliamps to remain powered on for an hour and you have a 3,000 mAh battery then that battery will last for two hours. One other commonly asked question is how long will this battery last. Lithium-ion batteries struggle in hotter climates, so make sure not to keep them in prolonged exposure to heat or sunlight. Each battery will have a set number of cycles it is guaranteed for, and you’ll want to pick ones with higher cycles anywhere from 500 to 1,000 cycles to ensure you’re getting a quality battery. Once your battery comes to the end of its life which will happen sooner or later, you will notice the decreased performance fairly quickly in ways like inability to hold a charge, getting hot while charging or discharging which will usually happen when the battery is about two years old. 18650 batteries should always be recycled at your nearest battery drop off center because the inside materials can still be harvested for use as opposed to letting them sit in the trash or a landfill.

What is the most powerful 18650 battery available?
Buying batteries can be confusing especially with how many different sizes, chemical makeup, voltage, and milliamps there are currently. 18650’s are fairly new and are very powerful so make sure you follow any and all instructions or directions before using or charging the battery to prevent any damage to the battery, your device or even yourself. 18650 batteries can vary in capacity but will always be made up of lithium-ion technology and will have a voltage of 3.7 but can go up to 4.2 on a full charge and they can range in capacity anywhere from

2300 mAh all the way to about 3600 mAh(Mili Amp Hours) which determines how long the battery will last before having to -recharge it. This will probably be the most important when deciding on which batteries to purchase. These 18650 batteries can realistically, only go up to 3500-3600 mAh. Any 18650 battery that you see claiming to be higher than that is either not being truthful, or they are using some sort of non-standard measurement system in order to make their battery look better artificially. Some vendors or retailers may even sell counterfeits that are re-wrapped to pass off as new and will print fake specifications on them. It is very difficult for a consumer to test the capacity of their battery, and so these companies can easily get away with it. This is something you typically see on Ebay or Amazon. Some of the better-made ones will have what is called PTC or PCB which is basically just a protection circuit that prevents overcharging of the battery and can make the cell a bit longer due to the included circuit protection. If you are using a device that requires two or more 18650 batteries then you will want to make sure you have the same capacity or milliamps for each battery in your device and the reason why is batteries with a lesser capacity will drain quicker than those with higher capacities and will cause the device to perform less efficiently and will have to take them out to charge up while your higher capacity batteries still have a ways to go before they need to be charged.

By | 2020-03-12T12:25:08+00:00 March 12th, 2020|Uncategorized|0 Comments

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