A 48-amp home charger delivers 11.5 kW; a 32-amp one delivers 7.7. On the 18 cars here with a sourced onboard charger, the bigger unit cuts an empty-to-full charge by 2.6 to 4.2 hours — but not one of them can use the full 11.5 kW, and for an average day’s driving the small charger finishes in under two and a half hours either way. Whether the upgrade is worth it depends on one question: how often do you arrive home empty?
Every car, at both powers
Hours are empty to full, through the car’s own onboard charger, with the 10 per cent charging loss included. “Miles per hour” is how much range a 7.7 kW charger adds in an hour, from each car’s EPA efficiency; it is blank for the four cars without a US rating.
| Car | Onboard AC | Usable pack | Full at 7.7 kW | Full at 11.5 kW | Saved | Miles / hour at 7.7 kW |
|---|---|---|---|---|---|---|
| Kia EV9 AWD | 11 kW | 96 kWh | 13.9 h | 9.7 h | 4.2 h | 17 |
| Nissan Ariya e-4ORCE 87 kWh | 22 kW | 87 kWh | 12.6 h | 8.4 h | 4.2 h | 19 |
| Ford Mustang Mach-E Extended Range RWD | 10.5 kW | 91 kWh | 13.1 h | 9.6 h | 3.5 h | 23 |
| BMW i4 eDrive40 | 11 kW | 81.3 kWh | 11.7 h | 8.2 h | 3.5 h | 24 |
| BYD Seal AWD Excellence | 11 kW | 82.5 kWh | 11.9 h | 8.3 h | 3.6 h | — |
| Porsche Taycan RWD | 11 kW | 82.3 kWh | 11.9 h | 8.3 h | 3.6 h | 19 |
| Hyundai Ioniq 5 Long Range RWD | 11 kW | 80 kWh | 11.5 h | 8.1 h | 3.4 h | 23 |
| Kia EV6 Long Range RWD | 11 kW | 80 kWh | 11.5 h | 8.1 h | 3.4 h | 23 |
| Tesla Model 3 Long Range AWD | 11 kW | 79 kWh | 11.4 h | 8.0 h | 3.4 h | 26 |
| Volkswagen ID.4 Pro | 11 kW | 77 kWh | 11.1 h | 7.8 h | 3.3 h | 23 |
| Volkswagen ID.7 Pro | 11 kW | 77 kWh | 11.1 h | 7.8 h | 3.3 h | — |
| Tesla Model Y Long Range AWD | 11 kW | 75 kWh | 10.8 h | 7.6 h | 3.2 h | 25 |
| Hyundai Ioniq 6 Long Range RWD | 11 kW | 74 kWh | 10.7 h | 7.5 h | 3.2 h | 27 |
| Ford Mustang Mach-E Standard Range RWD | 11 kW | 72.6 kWh | 10.5 h | 7.3 h | 3.2 h | 22 |
| Toyota bZ4X AWD | 11 kW | 69 kWh | 10.0 h | 7.0 h | 3.0 h | 25 |
| Volvo EX30 Single Motor ER | 11 kW | 65 kWh | 9.4 h | 6.6 h | 2.8 h | 24 |
| Tesla Model 3 RWD | 11 kW | 60 kWh | 8.7 h | 6.1 h | 2.6 h | — |
| Tesla Model Y RWD | 11 kW | 60 kWh | 8.7 h | 6.1 h | 2.6 h | — |
The Rivian R1T is not in the table because we hold no sourced figure for its usable capacity or onboard charger; it appears when we do.
No car here can take 11.5 kW
The number a home charger is sold on is what it can supply, not what the car can accept. Seventeen of these eighteen cars carry an 11 kW onboard charger (the Mach-E Extended Range’s is 10.5), so a 48-amp unit is throttled to 11 kW the moment it is plugged in — the “11.5 kW” column above is really the 11 kW column. Only the Ariya, with a 22 kW unit built for European three-phase supplies, could use more, and on a North American single-phase circuit it cannot get it. That is why the hours saved cluster so tightly: every car saves about 30 per cent, because every car is limited by the same 11 kW ceiling.
The practical consequence is that a 48-amp charger is the most any of these cars can use at home, and a 64 or 80-amp unit buys nothing for them.
The day you actually charge for
Empty to full is the number people compare, and it is the case that almost never happens. The average US driver covers about 37 miles a day. At 7.7 kW the least efficient car in the table, the EV9, recovers that in 2.1 hours; the Ioniq 6 does it in 1.4. Every car here refills an average day in under two and a half hours on the smaller charger, which is a fraction of any night.
Where 11 kW earns its cost is the turnaround: home at 22:00 with 10 per cent after a long day, out at 06:00. In eight hours the 7.7 kW charger puts about 55 kWh into the pack — enough to fill the Teslas’ 60 kWh LFP packs, the EX30 and the bZ4X, and to take the 80 kWh cars to about 80 per cent. The EV9 and the Mach-E Extended Range are left at 65 to 70 per cent. At 11 kW the same eight hours deliver 79 kWh, and every car in the table leaves full or close to it.
Which cars gain most, and which barely notice
The gain is proportional to pack size, so the cars that benefit are the big ones: the EV9, the Ariya and the Mach-E Extended Range each save around four hours, and they are also the cars that a 7.7 kW charger cannot fill overnight from empty. If you own one of them and regularly arrive home low, the 48-amp unit is the right specification; the Mach-E charging page makes the same point for that car specifically.
At the other end, the 60 kWh Tesla Model 3 RWD and Model Y RWD fill from empty in 8.7 hours on the smaller charger — inside any night — and save only 2.6 hours on the bigger one. For those cars, and for the EX30 and the bZ4X, the extra circuit capacity is money spent on a case that does not arise. Their LFP packs are also meant to be charged to 100 per cent regularly, which the slower charger does perfectly well; see electric cars with LFP batteries.
The wiring behind the two numbers
Under US electrical code a circuit may be loaded continuously to 80 per cent of its rating, so a 32-amp charger needs a 40-amp circuit and a 48-amp charger needs a 60-amp one. On a 240-volt supply that is 7.7 kW and 11.5 kW respectively. The 60-amp circuit is the part that costs: it needs heavier cable and a panel with the spare capacity, and in an older house that can mean a panel upgrade that costs more than the charger. If the panel is the constraint, a 32-amp unit on a 40-amp circuit — or even a 24-amp unit at 5.8 kW, which still refills an average day in about three hours — is the sensible answer, and the table above says what you give up.
If the 7.7 kW circuit is going in anyway, the natural follow-up question is whether a rooftop array can feed it. A 7.7 kW charger draws more than most residential solar systems produce at any given moment, so the answer depends on array size, when you charge, and whether there is a battery in between. Our sister site Solarsunlabs works through that sizing in its guide to charging an EV from solar.
Frequently asked questions
Is an 11.5 kW home charger worth it over 7.7 kW?
Only if you regularly need an empty-to-full charge overnight in a car with a large pack. For an average day’s driving, every car here refills in under two and a half hours at 7.7 kW. The larger unit saves 2.6 to 4.2 hours on a full charge, and needs a 60-amp circuit to do it.
Can an EV actually charge at 11.5 kW at home?
Most cannot. Seventeen of the eighteen cars here carry an 11 kW onboard charger, so a 48-amp, 11.5 kW unit is capped at 11 kW by the car. The Nissan Ariya’s 22 kW unit needs a three-phase supply, which North American homes do not have.
How many miles of range does a 7.7 kW charger add per hour?
Between about 17 miles an hour (Kia EV9) and 27 (Hyundai Ioniq 6), from each car’s EPA efficiency and allowing for charging losses. At 11 kW the figures are roughly 40 per cent higher: 25 to 38 miles an hour.
How long does it take to charge an EV at home from empty?
At 7.7 kW, between 8.7 hours (60 kWh Tesla Model 3 and Model Y RWD) and 13.9 hours (96 kWh Kia EV9) for the cars in this table. At 11 kW, between 6.1 and 9.7 hours.
Sources
Usable capacity and onboard charger rating are credited on each car’s page, mostly to EV Database and the manufacturer’s specification sheet. Miles per hour uses each car’s EPA combined rating from fueleconomy.gov. Charging time assumes 90 per cent AC charging efficiency, the same figure the per-car charging pages use.