Today, 18650 batteries can be found in many fields. This is because 18650 batteries offer significant advantages over other batteries and are relatively safe. To help you better understand how to get the most out of your Olight flashlight and extend the life of your batteries, we've compiled a complete list of the most frequently asked questions about 18650 batteries.
what is an 18650 battery?
The 18650 battery is the originator of lithium-ion batteries -- a standard lithium-ion battery model set by Japan's SONY company in order to save costs, where 18 means a diameter of 18mm, 65 means a length of 65mm, and 0 means a cylindrical battery.
Battery Name | 18650 lithium batteries |
Battery Diameter | 18mm |
Battery Height | 65mm |
Common Type | Lithium-ion battery |
Voltage | 3.7v、3.2v |
Common Capacity | 2000mAh/2600mAh/3000mAh |
Lithium battery (Li-ion, Lithium Ion Battery): Lithium-ion batteries have the advantages of being lightweight, having a large capacity, having no memory effect, and so on, so they are widely used. Many digital devices use lithium-ion batteries as power sources, despite their price relatively more expensive. The energy density of lithium-ion batteries is very high; their capacity is 1.5~2 times that of nickel-metal hydride batteries of the same weight, and they have a very low self-discharge rate. In addition, lithium-ion batteries have almost no "memory effect" and no toxic substances, which are also important reasons for their wide application. In addition, please note that the lithium battery is generally labeled on the outside of the 4.2V lithium-ion battery, 4.2V lithium secondary battery, or 4.2V lithium-ion rechargeable battery, so users must be careful when purchasing batteries. You must read the labels on the surface of the battery block to avoid mistaking the nickel-cadmium and nickel-hydrogen batteries for lithium batteries.
Type Difference
Lithium batteries are marked 3.7V or 4.2V are the same. It's just that the manufacturer's label is different. 3.7V refers to the typical voltage when the battery is discharged during use, while 4.2V refers to the voltage when it is fully charged. The common rechargeable 18650 lithium battery has a voltage of 3.6v or 3.7v, and it is 4.2v when fully charged, which has little to do with the power (capacity).
18650 battery mainstream capacity from 1800mAh to 2600mAh, (18650 power battery capacity is mostly in 2200~2600mAh), the mainstream capacity and even have a standard 3500 or 4000mAh or more have. It is generally believed that the unloaded voltage of lithium batteries to 3.0V or less is considered to be exhausted (the specific value depends on the threshold value of the battery protection board, for example, there are as low as 2.8V, and there are also 3.2V).
Most lithium batteries cannot be discharged with a no-load voltage below 3.2V, otherwise over-discharge will damage the battery (generally, lithium batteries on the market are basically used with protection boards, so over-discharge will also cause the protection board to fail to detect the battery, making it impossible to charge the battery).4.2V is the highest limit voltage for battery charging. It is generally believed that the lithium battery is fully charged when the no-load voltage is charged to 4.2V. During the battery charging process, the battery voltage gradually rises from 3.7V to 4.2V. Lithium battery charging can not charge the no-load voltage to above 4.2V, otherwise, it will damage the battery. This is the special place of lithium battery.
Advantages of 18650 lithium battery
✅High safety: 18650 lithium battery has excellent safety performance, will not explode or burn, is non-toxic, and is non-polluting.
✅Long life: 18650 lithium battery has a very long life, under normal use, it can be recycled more than 500 times, which is more than twice that of ordinary batteries. In order to prevent short circuit, the positive and negative electrodes of the 18650 lithium battery are separated, which greatly reduces the possibility of a short circuit. In addition, a protection board can be added to avoid overcharging and over-discharging the battery, further prolonging the service life of the battery.
✅Large capacity: The capacity of the 18650 lithium battery is generally between 1200mAh and 3600mAh. If multiple 18650 lithium batteries are combined to form a module, its capacity can even exceed 5000mAh.
how long does the 18650 battery last?
Most 18650 batteries have a life cycle of about 500 charge cycles. For example, the Olight 18650 battery. Once this threshold is reached, the battery will not reach 100% capacity and will only have approximately 80% of its initial capacity. Although you can still get enough power from the battery, its capacity will gradually decrease as the number of charge cycles increases.
Our smartphone batteries are also lithium batteries, and most people have experienced this when using their cell phones. Time and use will also slowly shorten the life of the battery.
🚩Please note: Studies have shown that the capacity of lithium battery cells decays more slowly at room temperature, while at high temperatures of 55°C and 65°C, the batteries exhibit rapid failure behavior. When the temperature is lower than -10℃, the capacity of the battery decreases sharply. Meanwhile, the performance of lithium batteries deteriorates at low temperatures, which is related to the reduced ionic conductivity of the electrolyte and the electrode materials.
how to charge an 18650 battery?
Depending on the brand of the 18650 battery, you may need to charge the battery as it was designed. If you use a charger that is not suitable for the type of lithium-ion battery, at best you may cause permanent damage to the battery, and at worst you may cause the battery to explode. To avoid lithium battery damage, please use a 18650 charger with overcharge, overcurrent, and overvoltage protection. So you can rest assured that the battery is safe.
🚩Friendly Notes: In order to fully utilize the life of your battery, we recommend that you make sure, as much as possible, that the battery is never fully discharged or that battery capacity is too low
Lithium battery charge and discharge principle
The working principle of lithium-ion batteries refers to their charging and discharging principle. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon as the negative electrode is a layered structure, it has a lot of micropores, the lithium ions that reach the negative electrode are embedded in the micropores of the carbon layer, and the more lithium ions are embedded, the higher the charging capacity.
By the same token, when the battery is discharged (i.e., the process of using the battery), the lithium ions embedded in the carbon layer of the negative electrode come out and move back to the positive electrode. The more lithium ions that return to the positive electrode, the higher the discharge capacity. The battery capacity we usually refer to is the discharge capacity.
It is not difficult to see, in the lithium-ion battery charging and discharging process, lithium ions are in the positive → negative → positive state of motion. If we liken the lithium-ion battery image to a rocking chair, the rocking chair ends for the battery poles, and lithium ions are like a good sportsman, running back and forth between the two ends of the rocking chair. Therefore, experts have given lithium-ion batteries a lovely name rocking chair battery.
Image From Google
Lithium battery charging and discharging process
Lithium battery charging control is divided into two stages, the first stage is constant current charging, when the battery voltage is lower than 4.2V, the charger will charge with constant current. The second stage is the constant voltage charging stage, when the battery voltage reaches 4.2V, due to the lithium battery characteristics, if the voltage is any higher, it will damage the battery, the charger will fix the voltage at 4.2V, and the charging current will be gradually reduced, when the current is reduced to a certain value (generally 1/10 set current), cut off the charging circuit, charging is complete indicator light is on, charging is complete.
Excessive charging and discharging of lithium-ion batteries can cause permanent damage to the positive and negative electrodes. Over-discharge leads to the collapse of the anode carbon layer structure, and the collapse will cause lithium ions can not be inserted during charging; over-charging so that too many lithium ions are embedded in the anode carbon structure, resulting in some of the lithium ions can no longer be released.
Some chargers are realized by using cheap solutions, which are not good enough in control precision, easily causing abnormal battery charging and even damaging the battery. When choosing a charger, try to choose a big brand 18650 lithium-ion battery charger, with a quality and after-sales guarantee, to extend the service life of the battery. Brand-guaranteed 18650 lithium-ion battery charger has four-fold protection: short-circuit protection, over-current protection, over-voltage protection, battery reverse connection protection function, and so on.
how long to charge the 18650 battery?
A single 18650 battery can usually be fully charged for about 3.5 hours.
how to test the 18650 battery?
The following methods can be used to test and detect the performance of lithium-ion batteries:
Voltage measurement: Using electrical testing tools such as a multimeter, you can directly measure the voltage of the battery to determine whether the battery is fully charged.
Capacity measurement: Use special capacity testing instruments, such as constant current discharge instruments, etc., to conduct charge and discharge tests on the battery to measure the actual capacity of the battery.
Internal resistance measurement: Use a professional internal resistance testing instrument to test the internal resistance of the battery, thereby judging the performance and health of the battery.
🚩Friendly reminder: Be sure to make good records during the test and carry out data statistics to facilitate data comparison and analysis. When testing, it must be well-marked to facilitate the distinction between good and bad.
18650 Battery, Accessories, Rechargeable Flashlight
If you're in the market for a new rechargeable battery, flashlight, or accessory, I highly recommend checking out Olight. Olight has established itself as a trusted leader in rechargeable lighting solutions for many years. Olight offers cutting-edge lithium-ion battery technology and its products excel in terms of efficiency, performance, and lifespan.
With a large and growing customer base, Olight has garnered thousands of satisfied customers who keep coming back for more. This is because they know that when they choose Olight, they are investing in reliable, high-quality products that come with a comprehensive guarantee.
Take a look at Olight's impressive lineup of products and don't hesitate to reach out to their friendly customer service team for recommendations or advice. Just like a trusted friend, Olight is dedicated to providing you with top-notch lighting solutions.
