For lithium-ion solar batteries, the State of Charge (SoC) should ideally be monitored continuously or very frequently using integrated systems like a Battery Management System (BMS) that employs Coulomb counting methods. Here’s why and how often you should check the SoC:
- Continuous or frequent monitoring is best: Modern lithium-ion battery systems often use a Coulomb counter method, which tracks the inflow and outflow of current in real time. This method integrates the current during use to estimate SoC dynamically without needing the battery to rest, enabling accurate and ongoing SoC estimation during battery operation.
- Recalibration after each charge cycle: Because small measurement errors can accumulate in Coulomb counting due to factors like sampling frequency, these systems recalibrate and reset the SoC estimate after each complete charge-discharge cycle for improved accuracy.
- Periodic checks using voltage method: Occasionally, especially after the battery has been at rest for some time, an Open Circuit Voltage (OCV) measurement can be used to verify or recalibrate the SoC reading. This is because OCV is a reliable indicator of SoC when the battery is not under load.
- Avoid full discharges and frequent deep cycles: It’s also recommended to keep the SoC between about 25% and 75% or higher to prolong battery life and avoid degradation. Frequent checks help maintain this optimal range and prevent deep discharges.
In summary:
You should use a battery system that monitors SoC continuously with Coulomb counting and recalibrates at each charge cycle. If you manually check SoC, do it after the battery rests or at least daily in active use to ensure accurate understanding of remaining capacity and to maintain battery health.
This approach balances accurate real-time tracking with periodic validation, helping prolong your lithium-ion solar battery’s lifespan and reliability.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-often-should-i-check-the-state-of-charge-on-my-lithium-ion-solar-batteries/
