BMW i4 eDrive40 Home Charger Size.

For the BMW i4 eDrive40's 81.5 kWh battery, we recommend a 80A Level 2 charger on a 80A breaker with 4 AWG copper wiring. This provides a full charge in approximately 4 hours and is well-matched to the vehicle's onboard charger capabilities.

A 80A double-pole breaker is recommended. Per NEC 125% rule, the breaker must be rated at 125% of the continuous load. A 80A continuous charger load requires a 80A breaker. Always hire a licensed electrician to verify your panel capacity and perform the installation.

4 AWG copper wire is recommended for a 80A charger circuit. This assumes a standard run of 25-50 feet. For longer distances, a heavier gauge may be needed to limit voltage drop to under 3%. Use our Wire Size Calculator for exact sizing based on your specific run length and amperage.

For a 80A charger, a hardwired installation is recommended. NEMA 14-50 outlets max out at 40A continuous, so a 80A setup requires a direct hardwired connection for safety. Hardwired installations are also more reliable long-term with fewer connection points that can fail.

Even a 16A (3.8 kW) Level 2 charger can work for the BMW i4 eDrive40 if you have sufficient overnight charging time. A full charge would take approximately 21 hours on a 16A charger vs. 4 hours on the recommended 80A. For most daily driving (40 miles), a 16A charger would recover that range in about 3 hours.