The 18650 battery is actually a lithium-ion cell made in a standard size of 18mm x 65mm. Nowadays, it is used a lot in flashlights, laptops, and other high-tech devices because of its convenience and rechargeability.
Normally, this type of battery can be charged for about 500 times. However, if you don’t use it properly, it will be broken earlier.
Below are 5 tips to extend the life of a 18650 battery:
1. Keep Your Batteries At Room Temperature:
Heat is one of the biggest factors that have a bad influence on your battery life. Normally, you should protect your 18650 batteries at a temperature between 20°C – 25°C (about 68°F – 77°F), in a dry room with moderated humidity levels.
Especially in case, your battery is fully charged, you had better not leave it in a car parking out under the sunshine. Even when it is being charged, it also should be put in room temperature to avoid overheating.
Many R&D centers have worked really hard to find out the impact of high temperature on your batteries. It was proved that each 8°C rise in temperature breaks the life of a sealed lead acid battery in half. For example, if your battery is expected to last in 3 years at 25°C, it will only last for 1.5 years when being kept at 33°C.
And more importantly, once your battery life is damaged by heat, its capacity can’t be restored. That’s why you should always pay attention to the place you leave your device.
2. Avoid Frequent Full Discharge:
You shouldn’t wait until your battery is fully discharged to recharge it. Electronic experts recommended that a 18650 battery should be recharged right after it drops down to 40%.
The reason is because lithium ion chemistry prefers partial discharge to deep discharge. If you discharge a lithium-ion battery below 2.5 volts, the built-in safety circuit opens to stop the flow of charge.
As a result, the battery looks like it has no charge. In this case, you can’t use the original charger. The only way is using a battery analyzer that features the boost function to recharge the unit.
Apart from the above, you also need to remember not to recharge a deeply discharged battery after leaving it for a long time, even several months.
3. Allow Partial Discharges:
As mentioned above, lithium-ion chemistry prefers partial discharge to deep discharge. Lithium-ion batteries don’t have a charge memory, so deep discharge cycles aren’t necessary.
A lot of people usually wait until the battery goes all the way down to zero, then recharge it to 100%.
In fact, you shouldn’t do that since lithium batteries have a limited number of cycles where they can be fully charged and discharged (normally 200 – 300).
After going beyond that limit, the battery life tends to decline. Therefore, instead of charging your device up to 100% every day, you should only fully charge it once a month.
4. Never Overcharge Your Batteries:
Perhaps you have already known this because it’s one of the most popular advice that you can hear from the customer service after buying a new electronic device like laptop or smartphone.
That’s true. Excessive charging can bring on thermal run away in a lithium battery. Technically, lithium-ion work well within the designated operating voltages. However, it would become unstable if being charged to a higher voltage.
Li-ion cannot absorb overcharge. When fully charged, the charge current must be cut off. If you keep charging continuously after that, it would lead to plating of metallic lithium and compromise safety.
In fact, 18650 or lithium-ion battery is not the only type of battery being negatively affected by overcharging. Lead- and nickel-based batteries are also known to melt down and cause fire if improperly handled. Therefore, you must be really careful whenever charging your device.
5. Store In A Cool Place At 40% Charge:
Not many people are doing this, but storing 18650 batteries at lower temperatures will slow their self-discharge rate dramatically. Many people even said that you could put the batteries in your fridge. But you shouldn’t really do that. You only need to keep it in a cool, dry, and non-refrigerated location.
Normally, a battery should be fully charged before being used so that it could be in the best condition.
However, it would be harmful to your batteries before storage. The best battery manufacturer usually stores lithium-ion batteries at 40% charge. This would allow a stable condition even in terms of a level of self-discharge.
In this case, certain reserve charge is necessary to keep a battery and its protection circuit operational during long periods of storage.
That’s all for the top 5 tips to extend the life of your 18650 batteries. If you remember and follow these tips, the lifespan of it would be extended and you can use them longer than expected.