Solar and EV Charging at Home: Sizing Your System for an Electric Car
Saraswati Solar Team · 22/3/2026 · 8 min
An EV is the biggest new load most homes will add this decade. How much extra solar it needs, and why you should add it at the design stage.
An electric car is the largest new load most households will add this decade. Charged from the grid it roughly resets the bill you just eliminated with solar. Charged from your own roof it costs almost nothing.
How much extra generation an EV needs
A typical electric car in India uses about 13 to 16 kWh per 100 km. Drive 1,000 km a month and you need roughly 150 units, plus charging losses. In our climate that is about 1.2 to 1.5 kW of additional capacity — a meaningful addition to a 3 kW home system and a minor one on a 10 kW system.
Size for the car you will own
If an EV is on the horizon, add its consumption to the sizing exercise now. Extending an array later means a second structure, possibly a second inverter and a fresh net metering amendment. Two extra kilowatts on day one cost far less than two kilowatts in year three.
Charge in the sun, not at night
Solar generates roughly between 9 a.m. and 5 p.m. A car parked at home during the day, or charged at weekends, runs almost entirely on self-consumed solar. Night charging draws from the grid and gets settled against exported units, which is fine under net metering but less valuable than direct self-consumption.
Practical wiring points
- A 7.4 kW AC home charger needs a dedicated circuit, correctly rated cable and its own RCBO
- Check your sanctioned load; adding a charger may require an enhancement from the DISCOM
- Put the charger on backed-up circuits only if your hybrid inverter and battery can genuinely support it — most cannot charge a car
- A schedulable or throttleable smart charger helps you match charging to solar output
Does a battery help?
For most homes, no. Exporting surplus and importing at night under net metering is cheaper than buying a battery bank large enough to fill a car. Batteries earn their place for backup, not for EV charging.
Tell us your daily running when we size your system and we will build the EV load into both the design and the savings estimate.