EV Charger Speeds Explained: 24 Amp vs 48 Amp Home Charging

Installing a home electric vehicle charger is one of the most convenient upgrades you can make if you own an EV. Instead of relying on public charging stations, you can plug in at home and start every day with the range you need.

But one of the most common questions homeowners have is simple: how fast will my EV charge?

The answer depends on the charger, the vehicle, the electrical circuit, and how much power your home can safely support. Most home EV chargers are considered Level 2 chargers and operate at 240 volts, but they can be configured at different amperage settings. Common charging speeds include 24 amps, 32 amps, 40 amps, and 48 amps.

To understand the difference, we can use a simple formula:

Charging power = volts × amps

Since most home EV chargers operate at 240 volts, the charging power looks like this:

24 amps × 240 volts = 5.76 kW

32 amps × 240 volts = 7.68 kW

40 amps × 240 volts = 9.6 kW

48 amps × 240 volts = 11.52 kW

The higher the amperage, the more power the charger can deliver to the vehicle. That means a 48 amp charger can charge significantly faster than a 24 amp charger, assuming the vehicle can accept that charging speed.

Now let’s look at a real-world example.

Assume the EV has a 100kWh battery. Many manufacturers recommend charging the battery to around 80% for regular daily use, rather than charging to 100% every time. In this example, let’s say the battery is currently at 30 kWh and the owner wants to charge it to 80kWh.

That means the vehicle needs to add about 50 kWh of energy.

At 24 amps, the charger delivers about 5.76 kW. To add 50 kWh, the charging time would be approximately: 50 kWh ÷ 5.76 kW = 8.7 hours

At 32 amps, the charger delivers about 7.68 kW: 50 kWh ÷ 7.68 kW = 6.5 hours

At 40 amps, the charger delivers about 9.6 kW: 50 kWh ÷ 9.6 kW = 5.2 hours

At 48 amps, the charger delivers about 11.52 kW: 50 kWh ÷ 11.52 kW = 4.3 hours

So in this example, charging from 30% to 80% on a 100 kWh battery could take about 8.7 hours at 24 amps, or about 4.3 hours at 48 amps.

For comparison, a standard 120V household outlet charges much slower than a Level 2 EV charger. Most standard outlets are 120 volts and are commonly limited to about 12 amps for continuous EV charging on a typical 15 amp circuit: 120 volts × 12 amps = 1.44 kW

Using the same example, if the EV needs to add 50 kWh of energy: 50 kWh ÷ 1.44 kW = 34.7 hours

That means charging from 30% to 80% on a 100 kWh battery could take about 35 hours from a standard 120V outlet. If the vehicle is plugged into a dedicated 20 amp outlet and charges at 16 amps, the math would be: 120 volts × 16 amps = 1.92 kW

50 kWh ÷ 1.92 kW = 26 hours

This is why standard outlets are usually best for very light daily driving or emergency charging, while a properly installed Level 2 home EV charger is much more practical for regular use.

Actual charging times can vary depending on the vehicle, the onboard charger, temperature, battery condition, charging efficiency, and the EV charger being used. However, this gives homeowners a simple way to understand why charger size and electrical capacity matter.

One important thing to know is that not every home can safely support a 48 amp EV charger. Many older homes still have 100 amp main electrical panels, and adding a high-powered EV charger can place a large continuous load on the electrical system.

For example, a 48 amp EV charger typically requires a 60 amp circuit because EV charging is considered a continuous load. On a home with a 100 amp main panel, that can be a major portion of the home’s available electrical capacity. If the home also has central air conditioning, electric heating, electric water heating, pool equipment, kitchen appliances, or other large loads, the panel may not have enough available capacity for a full-speed charger.

In those situations, the EV charger may need to be installed at a lower charging speed, such as 24 amps or 32 amps, to help prevent overloading the electrical panel. In other cases, upgrading from a 100 amp main electrical panel to a 200 amp panel may be the better long-term solution.

A 200 amp panel upgrade can provide more electrical capacity for modern home energy needs, including EV charging, solar, battery storage, heat pumps, induction cooking, and future electrical upgrades.

Slazik Electric can evaluate your existing electrical panel, review your home’s available capacity, and help determine the right EV charger setup for your needs. Whether your home can support a full 48 amp charger or needs a lower charging configuration, the goal is to install a system that is safe, reliable, and properly sized for your home.

Slazik Electric is currently offering 10% off EV charger installations and $500 off main electrical panel upgrades from 100 amps to 200 amps.

Contact Slazik Electric today to schedule a free estimate for your EV charger installation or electrical panel upgrade.