How are Lithium Battery Cycle Lives Calculated?
Recently, many distributors have told us that many people using mobile phones, electric vehicles, and energy storage devices have a fundamental question: Is the cycle life of lithium battery calculated by "one charge" or "using it all up and then fully charging it"? How is the lifespan of lithium battery calculated in solar system?
Today, Xindun Power will explain the professional standard in the simplest terms, so you'll know how to make your battery last longer.
Many people mistakenly believe that simply plugging in the charger counts as one cycle. This is completely wrong.
The industry's actual calculation logic is very consistent. Whether it's a small mobile phone battery or a large electric vehicle or energy storage battery, the rule is the same: a complete cycle refers to the process of the battery cumulatively discharging 100% of its capacity, not the action of "plugging it in once."
For the simplest example: If you use half the lithiumbattery today and then fully charge it, and then use half again tomorrow and fully charge it again, these two charging cycles combined constitute one complete cycle.
For example, if you frequently charge your battery only when it's at 60%, letting it drop to 30% and then charging it back up, you've only used 30% of the battery. This only counts as 0.3 cycles, far less than one.
Only when you add up all these small, infrequent uses of battery power to reach 100% does it count as a complete cycle. Therefore, charging before the battery is fully discharged won't add any extra cycles, nor will charging more often accelerate battery lifespan.
What truly damages the lithium battery isn't the number of charges, but rather the depth of charge and discharge. For example, frequently letting the battery drain completely before charging, or leaving it fully charged to 100% and plugged in for extended periods—this kind of high input, high output usage will maximize the "damage value" of each cycle.
The cycle life mentioned in professional tests, such as 1000 or 2000 cycles, doesn't refer to the maximum number of charges you can make. It refers to the total number of complete cycles completed when the battery capacity drops below 80% under standard charge and discharge conditions.
At this stage, the battery isn't unusable, but its range is significantly shorter, generally considered to have reached its design lifespan. Understanding the calculation method makes daily use much clearer.
There's no need to intentionally drain the battery completely before charging, nor should you fear frequent charging. In fact, shallow charging and discharging, and charging as needed, is the most beneficial approach for lithium battery. Maintaining the battery level between 20% and 80% effectively slows down capacity degradation, allowing the battery to last longer and more stably.
The above content is introduction to the cycle life of lithium battery. For more information about lithium batteries, remember to follow Xindun Power.