Everything You Need to Know About Lithium Battery Charging Cycles

Everything You Need to Know About Lithium Battery Charging Cycles

By Renogy
renogys blog Jul 19th 2022

Everything You Need to Know About Lithium Battery Charging Cycles

Lithium batteries, often known as Lithium-ion Polymer (LiPo) batteries, are non-aqueous electrolyte batteries that employ Lithium as the negative electrode. Lithium-ion Polymer batteries have quickly become the primary power supply for a wide range of applications and sectors, thanks to continued improvement.

Lithium-ion batteries, often known as Li-ion batteries, are extensively used in solar power kits. They make excellent batteries for solar panels, portable solar generators, and electric cars. You may also use them to power your tools when undertaking solar power maintenance. Lithium-ion batteries are low-maintenance, extremely efficient, and long-lasting.

Lithium-ion batteries may be used with a variety of solar systems. An on-grid solar system may be made more powerful by adding battery storage. On the other hand, solar batteries can provide you with more flexibility, capacity, and tranquillity if you live off the grid. We will now go through the charging cycles of lithium-ion polymer batteries in-depth to ensure optimal use.

What is a Charging Cycle?

A charging cycle is a full charge and discharge of a rechargeable battery. When you drain a battery when powering a gadget, you discharge it since the battery was charged before usage or purchase.

The standard technique for measuring rechargeable battery charge cycles is the number of charge cycles that a battery can tolerate before performance decreases.

The frequency of charge cycles, voltage, and battery life (milliamp hours) are all essential performance metrics for rechargeable batteries. A charging cycle might be a complete charge to discharge or a succession of partial drains that add up to the battery's capacity.

What is Deep and Shallow Charging?

A Lithium battery has a lifespan of 300 to 500 charging cycles. Assume that a full discharge can give Q capacity. Lithium batteries can deliver or supplement 300Q-500Q power in total over their lifetime if the capacity decline after every charging cycle is not taken into account. We can charge 600-1000 times if we use half of the capacity each time and 2400-4000 times if we use 1/8 each time.

Consequently, if you charge at random, the number of times you charge is unpredictable. In essence, no matter how a Lithium battery is charged, a total of 300Q to 500Q of power is always added. Consequently, we may conclude that the life of a Lithium battery is proportional to the battery's overall charge, not to the number of charges. Deep charge and shallow charging have similar impacts on lithium battery life.

Lithium batteries benefit more from shallow discharge and shallow charging. Deep lithium batteries charging is only required when the device's power module is calibrated for lithium-ion batteries. As a result, lithium-ion-powered gadgets are not restricted by the process: they may be charged at any time without compromising battery life.

Shallow cycle charging is designed to enable batteries to provide short bursts of energy and not be used for an extended period before being fully charged. Deep cycle ensures your battery can manage long-term use by reaching much below 50% discharge before needing to be recharged.

It's crucial to remember that Shallow Cycle batteries abhor being depleted over lengthy periods. If you want to care for your shallow cycle battery (and hence extend its life), install a discharge control circuit that will turn off the battery when drained to around 50% and replenish it as soon as possible. If it isn't clear, having a smart charge/discharge monitor is critical for maintaining the health of your deep cycle or shallow cycle battery.

How Many Cycles Can You Get Out Of A Lithium-Ion Battery?

A Lithium-Ion battery's average life span is 2 to 3 years or 300 to 500 charge cycles, whichever comes first. As we put it, a charging cycle is a duration of utilization when the battery is fully charged, completely drained, and wholly recharged.

For battery packs that don't go through complete charge cycles, we can assume a 2- to 3 years average lifespan. However, most lithium-ion batteries will survive much longer than the minimum, in the region of 10–15 years. These batteries may last up to 3 times as long as cheaper lead-acid batteries, which only last five to seven years.

Rechargeable Lithium-Ion batteries have a finite lifespan and will slowly lose their ability to retain a charge. This capacity reduction (aging) is permanent. The battery's capacity reduces with time, reducing the duration it can power the product (run time).

When not under use or stored, lithium-ion batteries go on to deplete (self-discharge) slowly. Make sure you confirm your battery's charge status regularly. The user handbook for the device usually contains instructions on how to check the battery state as well as how to charge the battery.

How Storage Affects your Battery's Lifespan

Because lithium-ion batteries shed less capacity when dormant compared to other battery types, they are one of the easiest solar batteries to store. When solar energy is only utilised rarely, such as in a summer cottage, the slow self-discharge rates are beneficial.

A lithium-ion battery can easily be stored for a year; just make sure it has some charge, ideally 50 to 60 percent, before putting it away. If you store the battery with some charge, it will last longer before self-discharge gets the voltage near the danger point.

These batteries may be stored at temperatures as low as -40 degrees Celsius without difficulty. In warmer regions, high temperatures might be a problem. To extend your battery's lifespan, avoid keeping it completely full or entirely empty.

It's better to conduct long-term storage as near to room temperature as practicable. As a result, stay away from extremely cold rooms or placing the device near a radiator. Moreover, if you're keeping batteries for more than a few months, make sure all cables are disconnected.

Do lithium batteries need to be cycled?

Yes, cycling can help extend your battery life. When a fully charged lithium battery is drained to 25% SoC (black), the capacity loss is the greatest; if entirely depleted, the capacity loss would be even more. Charging to 100% and draining to 50% results in a shorter lifespan than cycling between 85 and 25% (green or dark blue)—charging your Lithium-ion battery to 75% and discharging to 65 percent results in the lowest capacity loss.

How Do I Keep My Lithium-Ion Battery Healthy?

It's essential to know how to keep them healthy while you're charging lithium batteries. The amount of time a gadget may operate before it has to be recharged is referred to as " battery life." On the other hand, the length of time a battery lasts before being changed is referred to as "battery lifespan." The combination of actions you take with your device is one aspect that affects battery life and lifetime. There are ways to help regardless of how you utilise it.

Extending battery life reduces the economic and environmental consequences of new battery manufacture, including raw material consumption, extraction impacts, and greenhouse gas emissions, as well as the disposal of spent batteries.

It doesn't take long to find out what makes the battery maintain its present charge. What isn't commonly known is how to properly care for the battery. That is equally crucial. The battery will be able to run more effectively due to this. Here are some tips for keeping your lithium-ion batteries in good shape.

Use Partial Discharge Cycles

Lithium-ion battery packs should not be totally depleted and recharged frequently ("deep-cycling"). Utilising only 20 or 30 percent of the battery's capacity prior to recharging will greatly improve your battery life. Five to ten shallow discharge cycles are roughly equivalent to 1 full discharge cycle.

While millions of shallow discharge cycles are possible, keeping your battery fully charged reduces battery life. If at all possible, avoid full discharge cycles.

Avoid High Charge and Discharge Currents

High charging lithium batteries and discharging currents will reduce the their cylcle life, as high currents put a lot of strain on your battery.

Avoid Very Deep Discharges

Extremely deep discharges will irreversibly harm a Li-ion battery. Metal plating on the inside can cause internal shorting, rendering the lithium battery useless and even hazardous.

When charging or discharging a Lithium-ion battery, many battery packs feature protective circuitry that opens the battery connection whenever the voltage goes below 2.5 V or surpasses 4.3 V or when the current crosses a predetermined level.

Limit the Battery Temperature

Minimising battery temperature extremes, specifically avoiding charging below 0°C, enhances battery health. Charging at below zero temperatures stimulates metal plating, possibly leading to an internal short circuit, which generates heat making the battery volatile and hazardous. Many battery chargers feature a temperature sensor to make sure that charging does not happen at extreme temperatures.

Avoiding Charging Lithium Batteries to 100% Capacity

You may accomplish this by using a lower float voltage. Lowering the float voltage improves the cycle and lifespan of the battery at the cost of capacity. A float voltage dip of 100 to 300 mV can improve your cycle life by 2 to 5 times or more.

Avoid Overcharging

When a battery is charged to a greater voltage than required, this is known as overcharging. After a battery has been completely charged, supplying a continuous voltage to it is not advised since it can accelerate irreversible capacity loss and can induce interior metal plating. This may cause an internal short circuit, causing the battery to overheat and become unstable.

Avoid High Moisture

You should not store or use lithium-ion batteries in high-moisture environments. Your battery's life and performance can be harmed if exposed to dampness.

Use an Appropriate Battery Charger

Even though a battery charger has no influence on the discharge depth, battery temperature, or other factors that influence battery health, most chargers offer features that can help improve your battery health.

The float voltage and charge termination mechanism of a battery charger play a major role in increasing battery lifespan. Many Li-ion chargers have a set float voltage of 4.2 V (or less), although there are other options for 4.1 V and 4 V and variable float voltages. When charging a 4.2-V Li-ion battery, chargers with a lower float voltage can help extend battery life.

Battery chargers that don't provide lower float-voltage choices can nonetheless extend your battery life. Chargers using minimum charge-current termination techniques can extend battery life by choosing the appropriate charge-current threshold.

Only use a charger designed for lithium-ion batteries since they have a feature that allows you to customise the charge. Using the right charger might even help you limit harm to your battery. The charger that shipped in with your battery is the best option.

Is it ok to leave a lithium-ion battery on the charger?

To be safely and properly charged, lithium-ion batteries require a considerably simpler constant current, constant voltage, or CC/CV charging profile. Simply said, a voltage is established, and a current flows until the voltage is attained, at which point the current stops running automatically. This is the same approach with phone and laptop chargers.

With this understanding, it's evident that as long as the right voltage limit is preset for the lithium-ion battery you're charging, leaving a lithium-ion battery on the charger shouldn't be a problem. You will obtain a safe and complete charge on your battery as long as the CC/CV profile is utilised, the maximum voltage is at the proper level, and the current does not exceed the appropriate threshold.


Lithium-ion batteries are a significant advancement over earlier battery types. Lithium-ion batteries charge quicker, last longer, and offer a higher power density than conventional batteries, allowing for more battery life in a compact package. It's not unusual for a lithium-ion battery to last the maximum 500 charge/discharge cycles. When you understand how they function, you can make them work even better for yourself.

While not all Lithium batteries are made equal, they all require regular maintenance to reach their full capacity. This necessitates a grasp of their unique maintenance needs. You'll always have a dependable battery if you regulate the storage temperature, keep them dry, and ensure they're charged appropriately. 

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