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How many amps do you really need?
Updated
For most drivers, 32A to 40A is plenty. 48A is nice to have, not a need.
Charge time calculator
Estimate. Assumes 240V and about 10% charging loss. Your car's onboard charger may cap the speed below the charger's rating.
Amps, breaker and speed
| Charger output | Breaker needed | Power | Range added per hour (approx.) |
|---|---|---|---|
| 16A | 20A | 3.8 kW | 11 miles |
| 24A | 30A | 5.8 kW | 17 miles |
| 32A | 40A | 7.7 kW | 23 miles |
| 40A | 50A | 9.6 kW | 29 miles |
| 48A | 60A | 11.5 kW | 34 miles |
Range per hour assumes 3.3 miles per kWh and 10% charging loss, the same math as the calculator. Trucks and big SUVs get less.
Why the breaker is bigger than the charger
EV charging is a "continuous load" because it runs for hours. Electrical code requires the circuit to be rated 125% of the load. That is why a 48A charger needs a 60A breaker and matching wire.
Who should buy which size
- 32A: commutes under 60 miles a day, full panels, plug-in hybrids. The AIMILER 32A is the low-cost pick.
- 40A: most EV owners. An empty 77 kWh battery refills to 80% in about 7 hours. See the EVIQO 40A plug-in.
- 48A: long daily drives or trucks with huge batteries, but only if the car can accept it. The Emporia does 48A hardwired.
Most smart chargers let your electrician set a lower max output, so a 48A unit can run safely on a smaller circuit today and be turned up after a panel upgrade.