This calculator estimates battery capacity loss associated with vehicle-to-grid energy throughput. It converts exported and recharged energy into equivalent full cycles, then applies an assumed degradation rate per 100 cycles.
The result supports high-level V2G cost and battery-life planning. It does not replace battery telemetry or a chemistry-specific aging model, and it excludes calendar aging unless that loss is already built into the rate assumption.
1. Enter usable capacity
Use the battery capacity available for vehicle operation.
2. Add cumulative V2G export
Enter total battery-to-grid energy over the period being studied.
3. Set round-trip efficiency
This estimates the extra recharge energy required to restore exported energy.
4. Choose a degradation rate
Use a planning assumption for capacity loss per 100 equivalent full cycles.
5. Review estimated wear
Compare cycle count and capacity loss with the expected value of V2G participation.
One full cycle is represented by discharge and recharge throughput equal to twice usable capacity.
The percentage is the modeled share of original usable capacity lost from V2G cycling.
Temperature, depth of discharge, charging power, chemistry, and calendar age can materially change actual degradation.
Given: 75 kWh capacity, 3,000 kWh exported, 85% round-trip efficiency, and 1.2% loss per 100 cycles.
Calculation: Recharge energy = 3,000 ÷ 0.85 = 3,529.41 kWh. Throughput = 6,529.41 kWh. Cycles = 6,529.41 ÷ 150 = 43.53. Loss = 43.53 ÷ 100 × 1.2% = 0.52%.
Result: Estimated V2G-related capacity loss is about 0.52%.
Battery wear occurs during both discharge and recharge, so both directions contribute to cycle throughput.
Not exactly. Round-trip efficiency combines losses across export and recharge, while charging efficiency covers only energy flowing into the battery.
Yes. Many partial cycles accumulate into equivalent full cycles based on total energy throughput.
Only with care. Warranty limits are not necessarily linear degradation rates and may use different test conditions.
No. It models cycling-related loss unless calendar aging is deliberately included in the selected rate.