What is the lithium-ion battery life cycle?

You definitely don’t want to get into trouble when the battery is dead. Whether your deep-cycle battery has been in use for many years or you just bought a brand new battery, it’s important to know how long it should last. Many factors affect the lithium-ion battery life cycle, but before we get into them, we will introduce the exact meaning of the battery life cycle and how to calculate it. 

When you use the battery and charge it, it will slowly lose its ability to restore its original capacity. The life cycle of a battery is the number of charge and discharge cycles it can complete before it loses performance.

How do you calculate the lithium-ion battery life cycle?

In fact, the first time you discharge the battery, it will no longer be fully charged. Of course, this does not mean that your battery has reached the end of its life.

Before the end of the life cycle is determined, each manufacturer will provide acceptable performance and capacity reduction data. There is no standard test, but the general rule of thumb is that the battery life cycle is the number of cycles you get before you can’t charge the battery to more than 80% of its original capacity.

How to determine the depth of discharge?

Another way to understand the battery capacity is based on the depth of discharge. The depth of discharge is the percentage of the used battery capacity relative to the total capacity. For example, if a brand new battery rated at 100 Ah is discharged to 60 Ah, the discharge depth of this cycle is 40%.

If we review our definition of lithium-ion battery life cycle, if we cannot charge the same battery more than 80 Ah, we have reached the life cycle limit. Even when it is “fully” charged, we start with a depth of discharge of 20%.

How many times can a battery be cycled?

1-battery life cycle

The life cycle of a battery depends on the battery type and how you use it.

Lithium-ion battery life cycle

The expected life cycle rating of Maxworld Power lithium-ion batteries is between 3,000-5,000 cycles. Light use can exceed this level well. Each manufacturer will also provide a depth-of-discharge limit to reach its life cycle rating.

Usually, lithium battery manufacturers limit the depth of discharge to 80%. However, some manufacturers, such as Maxworld Power Batteries, rate their batteries as 100% depth of discharge. This means you can use 100% of the capacity without excessively damaging the battery.

Compared with lead-acid batteries, lithium-ion batteries are much less affected by the environment and discharge factors. This makes life cycle estimation more accurate.

Lead acid battery life cycle

There are many types of lead-acid batteries, each with a different life expectancy. Depending on how you maintain your battery and the type of battery you have, you can expect to get some time between a few hundred to a thousand charging cycles.

The life in lead acid depends to a large extent on light discharge and proper charging cycles. If the battery will be used for high power demand or deep discharge, the number of cycles of these batteries will be much less.

What will shorten the life of rechargeable batteries?

2-battery life

In addition to the type of battery you have, there are many other factors that affect the life cycle of the battery. It will help you maximize the performance and life of your battery if you understand them.

Temperature

The effect of temperature on battery life can be a bit confusing. You often hear that higher temperatures will improve battery performance, and low temperatures will reduce battery performance. This is correct when referring to capacity rather than life cycle.

The extreme temperatures of lead-acid and lithium batteries can shorten battery life. However, the degradation of lead-acid batteries is more severe. The optimal operating temperature of the battery is approximately 25 degrees Celsius or 77 degrees Fahrenheit.

A study found that at 77 degrees Fahrenheit, the performance of lithium batteries for the first 200 cycles dropped by about 3.3%. At 113 degrees Fahrenheit, the performance drops by 6.7% in the same number of cycles. On the contrary, for every 15°C increase over 77°C, the life cycle of the lead-acid battery will be reduced by half.

Surely, you can operate the battery at high temperatures, but if you are doing so for a long time will shorten the life of the battery.

Large depth of discharge

The depth to which you discharge the battery in each cycle directly affects the life cycle. The general rule of thumb for lead-acid batteries is to periodically cycle the battery to 50% depth of discharge (DOD) instead of 80% DOD, which will double your life cycle. Similarly, cycling to 10% DOD instead of 50% will increase the life cycle by approximately five times. Although this is not necessarily practical, the standard recommendation is to avoid discharging lead-acid batteries below 50% as much as possible.

Lithium batteries are not easily damaged due to excessive discharge depth. Similarly, most lithium battery manufacturers recommend not discharging below 80% DOD. Dragonfly Energy and Battle Born Batteries rate our batteries as 100% DOD.

The rated depth of discharge of Maxworld Power batteries is 100%.

Insufficient recharge cycle

It is very important to charge the battery fully and not partially. Let your battery complete the charging cycle and let it go through a conditioning phase. This conditioning phase decreases sulfation on the lead plates.

Due to its internal battery monitoring system (BMS), incomplete charging cycles have less impact on lithium batteries. However, if possible, it is still a good habit to fully charge your lithium battery.

Electrolyte loss

All deep-cycle batteries contain electrolyte solutions that can realize internal chemical reactions. In flooded lead-acid batteries, the electrolyte will evaporate. Technically speaking, only the water evaporates and the electrolyte is left behind. In any case, if you charge the battery irregularly, you will find that the battery life is significantly shortened.

Lithium batteries and sealed lead-acid batteries also contain electrolyte. However, because they are sealed, they do not need to be refilled. Since the lithium battery is completely sealed, no electrolyte loss will occur. Sealed lead-acid batteries can still be exhausted through the valve during rapid charging or overcharging. Over time, even this small loss of electrolyte can affect cycle life.

Electrode crystallization

Over time, all batteries will degrade slightly due to chemical changes in the battery. Some of these changes are caused by certain deposits formed on the electrodes. Lead sulfate crystals are formed in lead-acid batteries, while in lithium ions, metallic lithium accumulates.

These changes reduce the available chemicals for the reaction. This will also affect the internal resistance and eventually lead to battery failure when excessive damage occurs.

How to extend battery life?

Once you start to understand how different factors affect the life cycle of a battery, you can understand more clearly how to extend the life of the battery. Following some simple “best practices” can help you make the most of your battery, whether it is a lead-acid battery or a lithium-ion battery.

Use the battery at a moderate temperature as much as possible. Of course, this may not always be possible. It is best to store, charge, and discharge batteries at temperatures close to 77 degrees Fahrenheit.

If you are using a lead-acid battery, try to reduce the frequency of discharging the battery below 50% of its capacity. Ideally, the depth of discharge for each cycle should be between 10% and 50%. If you have a lithium battery, it may be reduced to 80% DOD, and in some cases, it may be reduced to 100% DOD. Please refer to the battery manufacturer’s recommendations to ensure safety.

In addition, if you have a lead-acid battery filled with water, make sure to fill up the electrolyte. Finally, charging the battery slowly helps reduce internal resistance and extend battery life.

Conclusion

All in all, the cycle life of batteries is the number of charge and discharge cycles that a battery can complete before losing performance. Lithium-ion battery life cycle is affected significantly by many factors.

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