The 18650 is a rechargeable battery used for electronics, and it becomes more and more popular. Of course, you and I are using them in flashlights, laptops, smoking devices, electric vehicles, and much more in our daily life.
It’s essential to know how to use, how to charge, and how to maintain it. The final part is hard, but today, I’d like to share with you five tips to prolong the life of the best 18650 batteries.
Let’s find out:
But first, I want to introduce you a significant parameter of 18650 cells which is called “the cycle life”, besides others like Capacity (mAh), Discharge Current (A), Charge Current (A).
Being charged and discharged accounts for one cycle. The more cycles your batteries have, the longer they last. Typically, newbest 18650 batteries have around 300 – 500 (charge, discharge cycles).
In this article, we will learn tips on how to extend the cycle life:
1. Keep the batteries in the recommended temperature
All battery producers recommend us to store or use batteries in the range of temperature from 20 to 25 degrees of Celcius.
If we keep the cells in lower or higher temperature than the recommendation, it will cause a loss in efficiency. Technologically, every 10 degrees deviation leads to a 20-30 mAh loss. Higher deviation, bigger loss, faster degradation.
I know we have winter seasons when the temperature goes down to the freeze. And you think I will tell you not charging your 18650 cells under this kind of weather. Yes, that’s what I want to say, never do that. The number of batteries life will drop dramatically and quickly.
Opposite to the coldness is the heat. In the same way, you shouldn’t leave or charge your batteries in hot places, for example in a car, near the oven in the kitchen,…
Heat is always the biggest factor that reduces lithium-ion battery life.
Also, when you are using or charging a 18650 cell, and it is getting hot, simply stop using or charging. Getting hot means the battery is over-stressed. Don’t let it exceed 60 degrees or else you have to buy a new one soon.
2. Don’t overcharge (above 4.2V), do undercharge (under 4.0V)
When we do the charging, there are two factors needed to be concerned: cycle life and capacity. If you care the cycle life more than the capacity, you may end up with a partial charge.
In the opposite, if you care the capacity more, you will have a full charge. However, when you do that, perhaps you are placing a burden on the batteries, called “overcharging”. It equates to reducing your battery life.
To extend the battery life, you should undercharge under 4.0V to add cycle life.
3. Lower the charge current (amps)
On the market today, many chargers can lower the charge current that helps you to charge faster.
It’s about 1 amp or higher. Faster but shorter; I’m talking about the battery life.
There’s a considerable difference in cycle life between varied amp currents. 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)
When discharging, you can decide the cut-off voltage as well as the amperage. If we use a higher amperage or called high-drain, the chances are that it will reduce both the capacity and the cycle life at the same time.
That’s why battery users should discharge with less amperage. Electronic giants like LG, Samsung, Sony, Panasonic usually perform their official test at 0.5 or 0.8 amps.
5. Increase Your Cut-off Voltage
Li-ion batteries don’t have the charge memory like NiCad batteries, so there’s no need for deep-discharge cycles.
As recommended to do a partial charge, we’re advised to do a partial discharge. Then we have the partial cycle, and it’s a good, proper way to decrease the burden on the cell, increase the number of cycle life and thus keep your battery last longer.
Batteries specialists say that we should let the Li-ion batteries to be discharged entirely after approximately 30 charging times. If we continue to discharge partially, it may cause “digital memory”.
It will reduce the precision of the device power measure. Thus, in case you can’t count how many times of charge, after using it for a period of time, just leave the device running out of battery and recharge it. This deed helps to recalibrate the power gauge.
If we discharge the 18650 batteries with the voltage below 2.5V per cell, a built-in safety circuit will open, and the cells will be thrown away easily. We can’t use the original charger any longer. From now on, you should only discharge to 3,2 V for the better.
Some people will have an extra battery for their device. To keep it last as long as the official one, don’t store it in a full charged status.
Because when you do that, you are setting the oxidation of lithium-ion at the highest rate. Instead, you should store the lithium-batteries at 40% discharge, in a refrigerator and absolutely not the freezer.
We have five simple and useful tips to extend the 18650 batteries life. It not only saves cost of replacing new ones, but also protects us from injury incident if it explodes.
Hope this article helpful to you.