What is battery’s State-Of-Charge: SOC

The state of charge can be defined as the state of available electrical energy in the battery, usually expressed as a percentage. Because the available energy will vary depending on the charging and discharging current, temperature, and aging phenomenon, the definition Of the State of Charge is also divided into two types: Absolute state-of-charge; ASOC) and Relative State-Of-Charge; RSOC). Usually the range of relative charged state is 0% – 100%, while the battery is 100% when fully charged and 0% when fully discharged. The absolute state of charge is a reference value calculated from the designed fixed capacity value when the battery is manufactured. The absolute state of charge of a new fully rechargeable battery is 100%; Even if the aging battery is fully charged, it can not reach 100% in different charging and discharging conditions.

The following figure shows the relationship between voltage and battery capacity at different discharge rates. The higher the discharge rate, the lower the battery capacity. When the temperature is low, the battery capacity also decreases

FIG. 1. Relationship between voltage and capacity at different discharge rates and temperatures

Battery capacity detection data is related to the characteristics of the battery itself, charging and discharging conditions, and the accuracy of the detection instrument itself. Each detection data of the same battery is not exactly the same, usually the same detection step is set when the battery capacity is detected, and the cycle test is conducted until the battery data is basically stable. Usually set 0.5C for charge and discharge test battery capacity, the test environment to maintain ventilation and heat dissipation, conditions can be carried out in the environment of air-conditioned room, the battery itself is heated when testing, reducing the external temperature can ensure the equipment life, reduce the maintenance rate and replacement rate, to ensure the continuous operation of the equipment.

If you want to customize your own photovoltaic solution today, please contact us.

E-mail: info@maxbo-solar.com
Submit a form

Published On: October 20th, 2023 / Categories: Design, Technology /

Let’s Make Things Happen

* Please fill in as fully as possible so that we can provide a more accurate proposal.

Add notice about your Privacy Policy here.

Let’s Make Things Happen

The Maxbo team of sales consultants will continue to enrich our own expertise and experience to empower the development of sustainable energy with rigor.


Maxbo CEO

You will need to provide: 1. the amount of electricity used. 2. the type and power of the load. 3. the electricity consumption habits (daytime/nighttime consumption). 4. the need to store electricity. 5. the need to feed electricity to the mains. 6. drawings or address of the installation site. 7. other special requirements

We can provide you with a quotation, a specification for all products, a circuit connection diagram and a diagram of the installation and placement of the PV panels. Any other requirements and adjustments needed can be discussed with our team.

We can meet the needs of most scenarios, whether your application is for domestic, commercial and industrial use, in remote areas, or for grid-level energy storage, we have experienced colleagues to design and deliver the right solution.

* Please fill in as fully as possible so that we can provide a more accurate proposal.

Add notice about your Privacy Policy here.

Title