Battery State of Health Calculator
Calculate battery SOH from capacity fade.
Inputs
Ah
Ah
years
V
Results
State of Health
88%
Current Energy
4.2 kWh
≈ 4 loads of laundry
Remaining Cycles to EOL1,333
Annual Degradation2.4%/yr
Capacity Lost12 Ah
Original Energy4.8
How to Use This Calculator
- Enter Original Capacity, Current Capacity, and Total Cycles.
- Set Battery Age and Nominal Voltage.
- Review State of Health (%) and Current Energy (kWh).
- Use Remaining Cycles to EOL and Annual Degradation (%/yr) to inform your decision.
How the result changes with Original Capacity
| Original Capacity | State of Health | Current Energy |
|---|---|---|
| 1,001 | 8.8% | 4.2 kWh |
| 3,501 | 2.5% | 4.2 kWh |
| 6,500 | 1.4% | 4.2 kWh |
| 9,000 | 1% | 4.2 kWh |
What each input means
- Original Capacity
- Original rated capacity when new.
- Current Capacity
- Current measured capacity.
- Total Cycles
- Total charge-discharge cycles completed.
- Battery Age
- Calendar age of the battery.
- Nominal Voltage
- Nominal battery pack voltage.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersOriginal Capacity = 100, Current Capacity = 88, Total Cycles = 2000, Battery Age = 5 = 5 input(s) provided
- Calculate State of HealthState of Health88 = 88
- Calculate Current EnergyCurrent Energy4.2 = 4.2
- Calculate Remaining Cycles to EOLRemaining Cycles to EOL = max(01333 = 1333
- Calculate Annual DegradationAnnual Degradation2.4 = 2.4
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