The 40-amp and 48-amp ratings are the two main choices for a Level 2 home charger on 240 volts. They differ by about 20% in power, but the bigger difference is the wiring each one requires. This article compares them so you can decide which fits your home and your vehicle.
The power difference
A 40-amp charger delivers 9.6 kilowatts on a 240-volt circuit. A 48-amp charger delivers 11.5 kilowatts. As a rule of thumb, the extra power cuts charging time by about one-sixth in the same vehicle. The product descriptions give an estimated range per hour of about 38 miles at 40 amps and about 46 miles at 48 amps.
Consider a 60 kWh battery. At 9.6 kW, it takes about 6 hours from empty. At 11.5 kW, it takes about 5 hours. Both are workable for overnight charging in most households, but only if the vehicle can accept that power. The section on vehicle limits explains why that matters.
Wiring: 50 amps or 60 amps
Because a continuous load may use at most 80% of the breaker rating, a 40-amp charger needs a 50-amp circuit. A 48-amp charger needs a 60-amp circuit. The 40-amp unit can be a plug-in model that connects to a NEMA 14-50 outlet. NEMA 14-50 is a 240-volt, 50-amp outlet, commonly used for RV hookups and some electric ranges.
A 48-amp unit must be hardwired, which means it is permanently connected to the circuit. A licensed electrician should handle hardwired work, and local permits or inspections may apply. Check with your local building department before you start.
Vehicle limits matter
Every vehicle has an onboard charger with a maximum AC rate. If your car's limit is below 9.6 kW, neither charger will run at its full rating, and the choice between 40 and 48 amps matters much less. Look up your vehicle's maximum AC charging rate before you decide.
Choosing between them
Choose 40 amps if your home already has a 50-amp circuit or a NEMA 14-50 outlet, if you want a simpler installation, or if your vehicle accepts about 9.6 kW or less. Choose 48 amps if you have a 60-amp circuit or can add one, want the fastest AC speed available on a home unit, and your vehicle can accept that power.
How this applies to EVIQO chargers
EVIQO lists a 40A (9.6 kW) NEMA 14-50 plug-in model and a 48A (11.5 kW) hardwired model. A single listed model with a J1772 connector can be installed as either a 40A plug-in or a 48A hardwired unit. The 40A and 48A options are also offered with the NACS connector, depending on the model. Each charger comes with a 25 ft cable and a 3-year warranty, and a 4-year extended warranty is available for an extra charge.