Due to the rapid progress of lithium battery technology, modern lithium solar power battery systems have rapidly replaced traditional lead-acid batteries, because manufacturers have developed intelligent modular systems to adapt to different energy storage applications.

For those who are new to solar energy, please refer to our introduction to solar power battery storage, including the advantages and disadvantages of household batteries. In addition, please refer to our introduction to different types of solar energy systems, including grid connected, off grid and hybrid battery systems. For those who want to compare lithium and lead-acid batteries, please refer to our article on lithium and lead-acid batteries.

Battery size

Unfortunately, a one size fits all approach is usually adopted when determining the battery size, which may lead to poor performance and fail to meet consumer expectations. This is usually due to two main reasons:

A battery that is too small - capacity is not enough to meet the needs of the family.

Super large solar power battery - the solar panel does not have enough power to charge the battery, usually in winter.

In order to avoid these problems, a qualified designer should select and size the battery according to many important factors, including: the size of the solar cell array (existing or new), the type of system (grid connected or off grid), the requirements of backup power supply, and most importantly, the energy consumption (KWH) at night or at night. Fortunately, most modern solar power battery systems are modular and scalable, so they can be sized accordingly.

Battery size or capacity is expressed in kwh. This is the total energy that the solar power battery can store. However, the available capacity may be different from the total battery capacity. Generally, the available capacity is limited to 80% to 90% of the total battery capacity to extend the service life and avoid potential battery shutdown at very low charging levels. For example, a lithium battery with a total capacity of 10kwh may limit its available capacity to 80% to extend its service life. Therefore, 8kwh of energy can be discharged every day. However, the remaining 10% to 20% are usually available in emergency situations, such as long-term power outages, depending on how the system is programmed.