"How many amps should my EV charger be?" usually gets answered with "as many as your panel allows." That is the wrong starting point. The right number comes from how many miles you need back each night, how many hours you have to do it, and the limit your car will accept. Most South Florida households need fewer amps than they think, and the amps they do not buy are amps the panel keeps for the AC.
The common sizes
Home Level 2 chargers come in a handful of output settings, each paired with a breaker at 125% of the output because EV charging is a continuous load (NEC 625.41 summary, Mike Holt). Power figures below are from Tesla's Wall Connector table (Tesla breaker table). The miles-per-hour columns are our estimates using a car that uses 25 or 30 kWh per 100 miles, which spans the 23 to 30 kWh per 100 miles range fueleconomy.gov shows for 2026 sedans and crossovers, and a 90% charging efficiency, inside the 84 to 93% range fueleconomy.gov gives (fueleconomy.gov label guide; fueleconomy.gov EV technology).
| Charger output | Breaker | Power at 240 V | Est. miles/hour at 30 kWh/100 mi | Est. miles/hour at 25 kWh/100 mi |
|---|---|---|---|---|
| 16 A | 20 A | 3.8 kW | About 11 | About 14 |
| 24 A | 30 A | 5.7 kW | About 17 | About 21 |
| 32 A | 40 A | 7.6 kW | About 23 | About 27 |
| 40 A | 50 A | 9.6 kW | About 29 | About 35 |
| 48 A | 60 A | 11.5 kW | About 34 | About 41 |
The formula behind those columns is simple: kW times 0.9, divided by kWh per mile. You can run it with the number on your own car's window sticker.
Work backward from your nights
Here is the calculation we do with customers:
- Heavy-day miles. Say 60 miles.
- Energy needed. 60 miles at 30 kWh per 100 miles is 18 kWh at the battery. Divide by 0.9 for charging losses: about 20 kWh from the wall.
- Hours available. If you only want to charge in an off-peak window, use that window. Say 8 hours.
- Power needed. 20 kWh divided by 8 hours is 2.5 kW.
- Amps needed. 2,500 watts divided by 240 volts is about 10.5 A.
So a 60-mile driver needs only about 11 A over eight hours. A 32 A charger covers that with a lot of room for a road trip or a storm top-up, and 48 A is headroom this driver may never use. Two drivers doubling up, or a 150-mile weekend, change the numbers, which is why we ask.
The car sets a ceiling
Every EV has a maximum Level 2 rate it will accept. The EPA's example: a vehicle with a 30 A limit "doesn't benefit from using a charger that can supply 80 amps" (EPA, charging details). Check the owner's manual or the manufacturer's spec page for the onboard charger rating, in kW or amps. If the car tops out at 32 A, a 48 A circuit buys nothing today. It may help a future car, which is the one good argument for going bigger if the panel has capacity to spare.
The panel sets the other ceiling
A 40 A charger on a 50 A breaker is a large new load on a 100 A or 150 A service that already carries central AC, a water heater, a range and perhaps a pool pump. We run a load calculation before recommending a size. When the math is close, there are three honest options:
- Choose a lower output. 24 A or 32 A often fits where 48 A does not, and the earlier worked example shows it still covers most drivers.
- Add load management. A device such as the RVE DCC-12 cuts power to the charger when the panel reaches 80% of the main breaker rating and restores it after 15 minutes below that level (RVE DCC-12 specification). See load management vs a panel upgrade.
- Upgrade the panel or service. Sometimes the right call, especially in older homes. See EV charger panel upgrades.
Adjustable chargers: set once, locked
Most wall chargers let the installer set the maximum current. Under the 2020 NEC, which Florida uses through its 8th Edition building code, an adjusted setting can count as the charger's rating only on fixed equipment with restricted access, such as a tool-required cover, a lock or password-protected software (625.42; NEC 625.42 text). That lets a 48 A-capable charger be installed on a 40 A circuit and set to 32 A. We set it, and we make sure you know not to raise it without a bigger circuit.
Above 60 A
Chargers rated over 60 A need a readily accessible disconnect that can be locked open (EC&M on NEC 625.43). Few homes need that much output. For most households 48 A is the practical top.
Two EVs
Two cars do not always mean two big circuits. Tesla's Wall Connectors can share a total power limit across up to six units over Wi-Fi, with each unit on its own branch circuit (Tesla power sharing), and Emporia lists load sharing too (Emporia chargers). Our post on two EVs in one home explains the setups.
Our usual recommendations
| Situation | Typical output | Why |
|---|---|---|
| One EV, under 60 miles a day, older or full panel | 24 A to 32 A | Covers the miles and leaves room for the AC |
| One EV, long commutes, panel with capacity | 40 A | Fast top-ups for storms and road trips |
| Two EVs, one charger or power sharing | 40 A to 48 A | Shared overnight window |
| Plug-in 14-50 outlet | 32 A to 40 A | 40 A is the ceiling on a 50 A receptacle |
For wire and breaker details, read EV charger breaker and wire size. For the full install picture, see Level 2 charger installation.
Questions homeowners ask
Is a 48 A charger worth it?
Only if your car accepts it, your panel can spare it and you regularly need fast top-ups. Otherwise a 32 A or 40 A setting does the same job overnight.
Can I lower the charger's amps later?
Yes. Lowering the setting needs no new wiring. Raising it requires a circuit sized for the higher setting.
Does a higher-amp charger cost more to run?
No. You pay for kWh, not for speed. The same miles take the same energy whether they go in fast or slow.
What amps does a Tesla Mobile Connector use?
32 A on a 14-50 outlet, 24 A on a 14-30 and 12 A on a standard 120-volt outlet, per Tesla's manual (Tesla Mobile Connector manual).
Size it once, correctly
KRW Electric (EC13012832) does the load calculation, recommends the output and installs the circuit and charger across Miami-Dade, Broward and Palm Beach, permit and inspection included. See EV charger installation or the Florida Home EV Charging Guide, and send us your car model and a photo of your panel to get a recommendation.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
