5 Tips for Extending 18650 Battery Life

5 Tips for Extending 18650 Battery Life

We’re all very familiar to the 18650 batteries, every single one of us uses them every day. Perhaps the name is new and strange to some people.

Essentially, 18650 Lithium-Ion batteries are the most popular type among the rechargeable batteries used in a lot of devices like flashlights, smoking devices, laptops, and more electronics.

I realize not many people know how to keep them longer though we all want that. I’m excited to share five tips for extending 18650 batteries life with you:

To prolong the 18650 cells, we need to know how to increase or at least maintain the number of cycle life. Cycle life is a significant indication of how long the batteries will last.

Being charged and discharged accounts for one cycle. Most of modern 18650 cells have approximately 300 to 500 cycles (300-500 charge + discharge times). More cycles mean more extended life. The batteries also have other parameters: Capacity (mAh), Discharge Current (A), Charge Current (A) besides.

1. Keep the batteries at the appropriate temperature:

All battery manufacturers suggest users utilize and store cells at the temperature above 20 and under 25 degrees of Celsius.

They say a little lower, or higher storage temperature than recommendation can cause inefficacy. It’s measured a loss from 20-30 mAh for every 10 degrees variation. The higher deviation leads to the bigger capacity’s loss, the bigger capacity’s loss leads to faster degradation.

We are unable to take control of the temperature. It’s God’s work. We just pay attention to too low or too high temperature and bring them away.

For example, in the winter when the temperature goes down to the freezing level, please don’t charge the batteries under that condition.  Unless you want the length of cells life will be cut down quickly.

Heat is also a batteries adversary like the coldness. Undoubtedly it will shorten the cell’s life. Never charge the 18650 batteries or leave your devices powered by batteries near hot places such as inside the car, oven in the kitchen. Don’t let it exceed 60 degrees or else you have to buy a new one soon.

We all encounter the situation that the batteries are hot while using or charging. The cells are trying to tell you that they’re over-stressed by getting hot. They can’t speak! Don’t keep using or charging but stop it instead.

2. Don’t overcharge (above 4.2V), do undercharge (under 4.0V)

There are two factors involved in the charging process that we need to concern: cycle life and capacity. We can’t have two of them at the same time. If you do a full charge, you will have your batteries worked at full capacity.

However, a full charge probably is a stress to the cells, resulting in reducing in the batteries life unintentionally.

In opposite, a partial charge can maintain or increase the number of batteries cycle life. And you have to accept an incomplete capacity.

You have to choose between cycle life and capacity. In the long run, you should select the cycle life to keep the batteries longer with you.

To do that, you should charge the li-ion batteries under the voltage 4.0V.

3. Lower the charge current (amps)

On the market today, there’re chargers labelled “fast chargers”. They cut down the charging time by lowering the current. It’s about 1 amp or higher.

Smart 18650 battery charger

That’s the pro, but the con is reducing the number of cycle life of 18650 cells. So you can use it in urgent cases but don’t use it regularly.

There’s a positive correlation between the number of cycle life and current amperage. The cycle number for 1.5, 1.0, 0.7, 0.5 amp is about 110, 200, 360, 640 relatively.

Notice the current when charging, because it affects your 18650 batteries a lot.

4. Lower the discharge current (amps)

Batteries users can opt for the cut-off voltage as well as the amperage. As recommended to charge with lower current, we also should discharge with a lower current.

If we use a higher amperage, the power will be drained away quickly. It means that it will reduce both the capacity and the cycle of life at the same time.

In official tests, electronic giants such as LG, Samsung, Sony, Panasonic perform at 0.5 or 0.8 amps currents. How don’t we follow them?

5. Increase Your Cut-off Voltage

Unlike NiCad batteries, Li-ion batteries don’t have the charge memory. So it’s not necessary to have deep-discharge cycles. Tip no.2 tells us to charge the batteries partially, thus reversely; we should discharge partially.

Combining them means that the battery consumes one partial cycle life. This is a good way to relieve the burden on the 18650 cells, leading to an increase in the number of cycle life. Hence, it prolongs the batteries life.

Having said that, there’re times the batteries need a full discharge. That’s when after about 30 charging times according to batteries specialists.

If we continue to do the partial discharge, perhaps it will cause the “digital memory”, leading to the decrease in the accuracy of the device power measure.

But I know that no one schedule and track the charging times. When you feel that you have used the batteries for a quite long period of time, leave them run out of power and recharge them later. This deed helps to recalibrate the power gauge.

If we discharge cells with the voltage below 2.5V per cell, the inbuilt safety circuit will open, and we may have to throw the batteries sooner than we expected. At that time, the official charger is used no longer. From now on, you had better only discharge to 3,2V.

Some people may want to have an extra battery for their device. It’s a good plan B, but the common mistake is that they keep it in a fully charged status when not being used.


Because by doing that, you are unintentionally setting the process of lithium-ion oxidation at the highest rate. If you also have the extra batteries, don’t do that. Instead, you should store the lithium-batteries at 40% discharge, in a refrigerator and absolutely not the freezer.

In conclusion

Above are the top 5 tips to expand the 18650 batteries last longer. They’re so easy to apply, just need a little attention. Then you can save money and save the cells as well. Share if you find it helpful to you.

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