Comparison Between Constant Voltage Charging and Constant Current Charging

When charging batteries, we either use constant current charging mode or constant voltage mode. As the name says, one of the values is kept constant while the battery is being charged. Both methods have their unique significances that make them the optimal choice in their use cases.

However, many users still have queries regarding the charging hours, efficiency, and cost for either of these charging methods. So, in this article, we will compare both charging methods for the following values.

Charging Hour

The time required to charge a battery is crucial for different projects and various applications including consumer electronics, EVs, and gadgets. So, when you are working with such applications where the charging duration is crucial, it is important to go for the optimal charging strategy to meet your specific needs.

Constant Voltage Charging

Constant voltage charging means that you will have variable current for charging the battery through different charging stages in the complete cycle. When the battery has a lower voltage than that of the charging current, it will absorb a high current to raise the charging level.

When the voltage of your battery increases near the charging voltage, its current requirements will decrease, and it prevents overcharging. This method helps in precision charging, and it also allows us to work with fast charging technologies. However, it is crucial to carefully monitor and control the initial charging phases in this type of charging. This is because that period can lead to stress on the battery.

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Constant Current Charging

In this type of charging, we induce the battery to a constant current level regardless of its voltage and the difference between battery and charging voltage. This method allows for maintaining a simpler charging process where we do not have to adjust the current according to the battery voltage.

Working with this method of having constant current can be very helpful for applications where we need to predict the charging time and other metrics. However, it may not be as fast as the previous method. This method still provides good charging times since the battery energy absorption rate is high in the early charging stages.

Charging Efficiency

The next most important element to consider when working on battery charging methods is efficiency. In today's world, we are not only focused on charging the battery, but we focus on efficiency as well. That efficiency is responsible for adequate energy consumption and battery longevity, so it is crucial.

Both the constant current and constant voltage options offer different charging efficiency values and here is all you need to know about them:

Constant Voltage Charging

When we work with the constant voltage charging model, it focuses on adjusting the charging current for the battery dynamically according to its ongoing charging state. This charging method is efficient in the later stages of charging batteries where we need to handle overcharging and need to prevent potential battery damage.

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This method works by maintaining a constant voltage and reducing the charging current gradually. This way we minimize energy loss and heat generation when charging batteries. These are two of the biggest negative factors for charging efficiency and handling them helps us improve battery charging and life cycle.

Constant Current Charging

The method of charging batteries with a constant current and variable voltage is efficient throughout the charging process. This is because the method gives high efficiency from the initial stages of charging when the battery absorbs high current without causing any efficiency-related problems.

While this efficiency is significantly high in the early charging stages, it may not be the same in the later stages of charging the battery. This is because when the battery is close to its full capacity, the rate of acceptance of charging decreases. So, maintaining constant current can bring inefficiency in the following means:

Increased heat production

Potential energy wastage

Decrease in charging current.

Charging Cost

The last important factor to consider when charging batteries is the charging cost. It has become very important because the size of batteries is getting bigger with growing applications. A common example is the EV industry where we not only have cars but more commercial vehicles like trucks are moving over to this technology.

So, here is how the two charging methods perform in the case of charging cost:

Constant Voltage Charging

Charging with constant voltage means that we will need more sophisticated charging control circuitry for adjusting the charging statistics. This is the technology that will ensure that the voltage remains constant while charging and the current is adjusted right according to the battery's requirements for gaining maximum efficiency.

This system of charging batteries with high efficiency can lead to better battery life and improved capacity. However, it is not cheap to set up since the equipment and set-up costs can go high. With that investment, it brings cost benefits by reducing energy wastage and prolonging battery life. Hence, the long-term expenses of charging batteries are lowered.

Constant Current Charging

Going with constant current charging will be a much simpler and cheaper option initially. It is because we do not need to control the charging current continuously to efficiently charge the battery and this simplicity makes initial setup cost low. However, it is important to note that while this initial setup cost is low, energy consumption may increase.

This mode of charging potentially has higher operating costs because of the less efficient charging process at different stages of the charge cycle. Especially when the charger is not disconnected even when the battery is full since that will keep consuming electricity

Final Words

Charging with constant current means that the voltage will be variable for different charging states of the battery. Similarly, charging with constant voltage means that the current will vary for different phases of charging the battery. Both these charging methods work differently and have different types of benefits of charging the battery.

With the differences discussed in this article, when you are working on a project that requires charging a battery, you may opt for the right option that is more efficient for you.