State of Charge

Description

State of Charge (SOC) KPIs monitor BESS performance and health. Two key metrics help identify utilization patterns and operational efficiency:

1. Average SOC - The mean state of charge over a time period
2. Resting SOC - The state of charge when the battery is idle

Average SOC

Why It Matters

• Battery Health: Extreme SOC levels (very high or very low) accelerate battery degradation
• Longevity: Operating within optimal SOC ranges extends battery lifespan
• Performance: Consistent extreme SOC can reduce capacity and power capability over time

How It's Calculated

1. Collect SOC data at regular intervals
2. Calculate the arithmetic mean for the time period

Resting SOC

Why It Matters

• Battery Stress: Prolonged storage at extreme SOC levels causes chemical stress
• Aging: High resting SOC increases calendar aging, low resting SOC can cause capacity fade
• Safety: Extreme resting SOC levels may indicate potential safety concerns

How It's Calculated

1. Collect SOC and power flow data
2. Identify periods with minimal power flow
3. Calculate mean SOC during these resting periods