Can a 24V 200Ah lithium battery be charged by a 12V 30A MPPT charge controller?

Using a 12V 30A MPPT charge controller to charge a 24V 200Ah lithium battery isn’t recommended since it may not be safe, efficient, or practical due to voltage, current, charging method, C-rate, safety hazards, efficiency, and complexity considerations.

Here is a more detailed explanation for that:

Voltage Mismatch

A 12V 30A MPPT charge controller is designed for charging 12V battery systems, whereas the battery in question is a 24V system.

The voltage of a 12V 30A MPPT charge controller is too low to effectively charge a 24V battery.

Using a charge controller with a different voltage rating than the battery can lead to improper charging, reduced battery life, and even damage to both the charge controller and the battery.

Current Incompatibility

The charging current required for the 24V 200Ah lithium battery depends on its recommended C-rate.

The C-rate is a measure of the rate at which a battery is charged or discharged relative to its capacity. It helps determine a safe charging current to maintain battery health, longevity, and safety.

If we assume a C-rate of 0.2C for the 24V 200Ah lithium battery, the required charging current can be calculated as follows:

Charging current = Battery capacity x C-rate
Charging current = 200Ah x 0.2
Charging current = 40A

In this scenario, the battery needs a 40A charging current for optimal charging.

However, the 12V 30A MPPT charge controller can only deliver a maximum of 30A, which is insufficient to charge the battery at the optimal rate.

Inefficient power conversion

Even if you attempt to use a step-up converter to match the voltage between the 12V charge controller and the 24V battery, you will still face issues with the charging current.

Stepping up the voltage from 12V to 24V would likely halve the available current (from 30A to 15A).

This would further increase the charging time and decrease the efficiency of the charging process. Additionally, voltage converters introduce additional inefficiencies and losses in the system.

Charging Method Incompatibility

Different types of lithium batteries require different charging methods or algorithms to ensure safe and efficient charging.

If the charge controller is not compatible with the specific type of lithium battery being used, it may not be able to provide the appropriate charging method or algorithm, resulting in incomplete charging, reduced battery life, or even damage to the battery.

Complexity

Using a step-up DC-DC converter or multiple charge controllers to charge a 24V 200Ah lithium battery with a 12V 30A MPPT charge controller could add complexity to the charging system.

This could result in additional wiring and components, which could increase the cost and maintenance requirements of the system.

Battery management and safety

Lithium batteries require precise charging parameters and management for optimal performance and safety.

Using a charge controller with mismatched voltage and current ratings can lead to poor battery management, increased risk of overcharging, and potential safety hazards.

It’s important to choose a charge controller that is specifically designed for the voltage and capacity of the battery being charged, and to follow proper charging procedures to ensure safe and efficient operation.