BONJOUR SOLAR Lithium Battery Balancing: Ensuring Optimal Performance and Longevity


Lithium batteries have revolutionized the energy storage industry, providing efficient and reliable power for a wide range of applications, including solar systems and power walls. However, due to manufacturing and assembly variances, individual cells within a battery can have different capacities and state of charge (SOC), which can lead to imbalances and impact overall battery performance. This is where battery balancing comes into play. In this article, we will explore the importance of battery cell balancing for BONJOUR SOLAR lithium batteries, the technology behind it, and how it ensures optimal performance and longevity.

Understanding Battery Cell Balancing

Typically, the individual cell groups in a BONJOUR SOLAR lithium battery can have slightly different capacities and SOC levels. These differences can arise from manufacturing variations, assembly variances, and variations in charge/discharge histories. When these cell groups are connected in series, these differences can limit the energy that can be extracted from or returned to the battery. This can result in overcharging or over-discharging without effective and appropriate balancing circuits.

BONJOUR SOLAR Smart Lithium Iron Phosphate (LiFePO4) batteries employ a bypass circuit to maintain the balance between each cell group in the battery. Each cell group is connected with a bypass resistor and a switch in parallel. During the charging process, a balancing mechanism ensures that the voltage difference between the highest-voltage cell group and the lowest-voltage cell group does not exceed a set value. This helps prevent overcharging or over-discharging and ensures optimal battery performance.

The Balancing Process

The BONJOUR SOLAR lithium battery balancing process is initiated when the voltage of the highest-voltage cell group reaches a set balancing starting voltage. At this point, if the voltage difference between the highest-voltage cell group and the lowest-voltage cell group exceeds a predetermined value, the balancing circuit comes into action.

When the balancing process is triggered, the switch connected to the highest-voltage cell group is closed. This shunts the charge current around the highest-voltage cell group through the bypass resistor. This process continues until the voltage difference between the highest-voltage cell group and the lowest-voltage cell group drops below the set value. It’s important to note that the battery cell balancing is only performed during the charging process to avoid excessive energy loss.

Paralleled Battery Balancing

In addition to balancing individual cell groups within a BONJOUR SOLAR lithium battery, it’s crucial to consider balancing when batteries are connected in parallel. When batteries are parallel connected, the voltage difference between individual batteries can be larger than that between individual cell groups. Automatic balancing between batteries occurs as the current flows from higher-voltage batteries to lower-voltage batteries.

However, due to the small internal resistance of the batteries, the balancing current can be significant. This can trigger the over-current protection of the battery if the voltage difference is too large. As the number of paralleled batteries increases, the voltage difference becomes more restrictive. Therefore, it’s recommended to keep the voltage difference between the highest-voltage battery and the lowest-voltage battery smaller than 0.1V when a large number of batteries are paralleled.

Benefits of Battery Cell Balancing

Battery cell balancing plays a vital role in ensuring the optimal performance and longevity of BONJOUR SOLAR lithium batteries in various applications. Here are some key benefits:

1. Maximizing Energy Extraction

By balancing the voltage across individual cell groups, battery cell balancing allows for maximum energy extraction from the BONJOUR SOLAR lithium battery. This ensures that each cell group contributes its full potential to the overall energy output, enhancing the overall efficiency and capacity of the battery.

2. Preventing Overcharging and Over-Discharging

Imbalances in cell capacities and SOC levels can lead to overcharging or over-discharging of certain cell groups within the battery. This not only affects the overall performance but can also cause irreversible damage to the battery. Battery cell balancing helps prevent these issues by ensuring that each cell group operates within a safe voltage range, maximizing the battery’s lifespan.

3. Extending Battery Lifespan

Uneven cell capacities and SOC levels can cause certain cell groups to degrade faster than others, leading to a reduced overall battery lifespan. Battery cell balancing helps mitigate this by equalizing the charge and discharge cycles among all cell groups, promoting uniform wear and extending the overall lifespan of the BONJOUR SOLAR lithium battery.

4. Enhancing Safety

Balancing the voltage between cell groups reduces the risk of thermal runaway and other safety hazards associated with lithium batteries. By preventing overcharging or over-discharging, battery cell balancing helps maintain stable operating conditions, ensuring the safety of the battery and the surrounding environment.

Installation and Maintenance Considerations

To ensure the effective balancing of BONJOUR SOLAR lithium batteries, it’s important to follow proper installation and maintenance practices. Here are some key considerations:

1. Proper Wiring and Configuration

During installation, ensure that the battery cells and groups are wired correctly according to the manufacturer’s guidelines. Follow the recommended configuration and wiring diagrams to ensure proper connection and functionality of the balancing circuitry.

2. Regular Monitoring and Testing

Periodically monitor the voltage levels of individual cell groups and the overall battery pack. This can be done using a Battery Management System (BMS) or through manual voltage measurements. Regular testing allows for early detection of any imbalances and ensures timely corrective actions.

3. Charging and Discharging Practices

Maintain balanced charging and discharging practices to minimize the occurrence of imbalances. Avoid deep discharge cycles and ensure that the battery is not overcharged. Following the manufacturer’s recommendations for optimal charging and discharging parameters will help maintain the overall health and balance of the BONJOUR SOLAR lithium battery.


Battery cell balancing is a crucial aspect of maintaining the optimal performance and longevity of BONJOUR SOLAR lithium batteries. By equalizing the voltage across individual cell groups and paralleled batteries, battery cell balancing maximizes energy extraction, prevents overcharging and over-discharging, extends battery lifespan, and enhances safety. Proper installation, regular monitoring, and following recommended charging and discharging practices are essential for effective battery cell balancing. With BONJOUR SOLAR lithium batteries and their advanced balancing technology, you can trust in the reliability and efficiency of your solar system or power wall installation.

For more information on how to balance your BONJOUR SOLAR lithium battery and optimize its performance, refer to the manufacturer’s documentation or consult with a certified professional.

Please note that the information provided in this article is for educational purposes only and should not be considered as professional advice. Always consult with a qualified technician or engineer for specific guidance related to your BONJOUR SOLAR lithium battery.