Three-Phase vs Single-Phase EV Charging

Single-Phase Power

Single-phase power is the standard residential supply in most of India. It uses two wires (line and neutral) and delivers power at 230V. Maximum current is typically 32A, giving a theoretical maximum of 7.4 kW. Most home connections are rated at 5 kW or 10 kW by the DISCOM.

For EV charging, single-phase supports chargers up to 7.4 kW. A 7.4 kW charger can add roughly 35-45 km of range per hour to a typical EV. For overnight charging, this is more than sufficient.

Three-Phase Power

Three-phase power uses three live wires, each carrying 230V but offset by 120 degrees. This delivers higher total power: up to 22 kW for EV charging (32A per phase at 400V). Three-phase connections are standard in commercial buildings and some larger residential properties.

• 11 kW (16A per phase): Common in European home chargers, gaining traction in India
• 22 kW (32A per phase): Maximum AC charging speed, useful for commercial and fleet applications
• Three-phase supply provides more balanced loading on the electrical network
• Voltage drop is lower on three-phase circuits for a given power level

Does Your Car Support Three-Phase Charging?

Just because your building has three-phase supply does not mean your car can use it fully. The onboard charger in the vehicle determines maximum AC charging speed. Many EVs sold in India have single-phase onboard chargers rated at 7.4 kW. Plugging into a 22 kW three-phase charger will still charge at only 7.4 kW.

Check your vehicle's specifications for onboard charger rating. If it lists 11 kW or 22 kW AC charging, it has a three-phase onboard charger and can benefit from a three-phase EVSE.

Upgrading from Single-Phase to Three-Phase

If you need faster charging and your home has only single-phase, upgrading to three-phase requires an application to your DISCOM. The process involves fees, possible meter replacement, and potentially upgrading your distribution board. Costs vary by state but typically range from Rs 5,000 to Rs 25,000.

Before upgrading, verify that your EV actually supports three-phase charging. If it does not, you are paying for a supply upgrade that delivers no benefit for EV charging, though it may help with other high-power loads.