How it works
Battery energy=capacity×(target−start)/100; wall energy=battery energy/efficiency; hours=wall energy/average wall kW.
Input definitions
- Usable battery capacity (kWh)
- Enter the value in the labeled unit.
- Starting state of charge (%)
- Enter the value in the labeled unit.
- Target state of charge (%)
- Enter the value in the labeled unit.
- Average wall power during charge (kW)
- Enter the value in the labeled unit.
- Wall-to-battery efficiency (%)
- Enter the value in the labeled unit.
- Electricity price per kWh
- Enter the value in the labeled unit.
A worked example
- Usable battery capacity (kWh)
- 60
- Starting state of charge (%)
- 20
- Target state of charge (%)
- 80
- Average wall power during charge (kW)
- 7.2
- Wall-to-battery efficiency (%)
- 90
- Electricity price per kWh
- 0.3
Assumptions & limits
Fixed average power, battery capacity and entered efficiency. Excludes charger/session fees, temperature effects and a detailed tapering curve.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Does this replace a circuit or electrical safety assessment?
No. The result uses the idealized model shown. Component tolerance, temperature, fault conditions and installation requirements need separate evaluation.
How does the EV charging time and cost tool work?
Battery energy=capacity×(target−start)/100; wall energy=battery energy/efficiency; hours=wall energy/average wall kW.
What are the assumptions and limits of EV charging time and cost?
Fixed average power, battery capacity and entered efficiency. Excludes charger/session fees, temperature effects and a detailed tapering curve.