What’s the Difference Between a 32 Amp vs. 40 Amp EV Charger?


We get it: You want to buy the best EV charger for your home, not get a degree in electrical engineering. But when it comes to the specifics regarding which unit is best for you, it can feel like you need at least a course or two to determine what you should get. When looking at the details of a unit, you may notice that it will say whether it is a 32 or 40 amp EV charger, and while it may seem like more is better, it may not be necessary for your needs. So we’ll break down 32 amp versus 40 amp EV chargers, what it means, and what is best for your electric vehicle.

What Are Amps?

While you have probably seen the term amp on electrical products and their documentation, it’s likely you don’t remember the specifics of what you learned in physics class. Amps — short for amperes — is a scientific term for a unit of electrical current. It defines the strength of a constant current of electricity. A 32 amp charger, therefore, has a lower strength of constant electrical current versus a 40 amp charger by a measure of eight amps. 

How Are Amps Used?

Every electrical appliance or device in your home that plugs into an outlet or is hardwired to the circuit takes a specific amount of amps depending on its electrical need. A hairdryer, television and electric range oven all require different amounts of amps to run, but if you run them all at once, you’d need to be able to accommodate the total amount of all three. 

They also all tend to pull power off of the electrical panel in your home, which means there’s a finite amount of amps available based on how much your system can provide you with. Because there’s a specific amount of amps available from your electrical system, all the amps used at one time need to add up to less than the overall amps available — like everything, you can’t use more than you have.

Your home only has so many amps (homes typically provide between 100 and 200 amps distributed amongst a number of circuits) to distribute between the devices that need electricity at one time. As the amount of amps needed increases toward the total amount available, you’ll notice lights flickering or power dwindling; if it reaches capacity, your circuit breaker will flip as a safety precaution to prevent any electrical fires or other issues.

The more amps it takes to use a device or appliance, the less there is available. 40 amps uses eight more amps from your system than 32 amps does. 

32 Amp Versus 40 Amp EV Charger

But if your home has 100-200 available amps, what difference can eight amps make? What is the difference between a 32 amp EV charger versus a 40 amp EV charger?

What it comes down to is that the more amps an EV charger can use, the more electricity it can deliver to the vehicle at one time. This is similar to the amount of water coming out of a faucet: when it’s open just a little, a smaller stream of water will come out of the faucet versus when you open the valve more. Whether you’re trying to fill a cup with a small or large stream from the faucet, the cup will eventually fill, but it will take longer with a smaller stream.

EvoCharge EVSE Level 2 EV Charging Station

EvoCharge’s standard EVSE Level 2 charger is a simple plug-and-charge solution for the basic needs of charging your vehicle at home quickly and safely.

The amount of amps used is important when time is a factor, like when someone is adding charge to their vehicle while running into the store for a few moments; in that situation, you hope the charging unit will have a higher amperage so it fills more quickly. However, if you’re charging at home, especially overnight, the extra time is usually unnecessary. You don’t need the extra eight amps in that situation and can get by fine with a 32 amp EV charger that will still charge your vehicle faster than a Level 1 EV cable while drawing less amperage off the circuit it’s connected to. 

This seemingly small difference can lead to big reasons for a homeowner to choose a 32 amp EV charger versus a 40 amp EV charger. While your home may have 100-200 amps available, they aren’t all available on the same circuit. Instead, they’re distributed — that’s why when a breaker is flipped it may require trying to figure out which needs to be reset.

A 32 amp EV charger is recommended to be installed on a 40 amp circuit — a common amount for a circuit to be able to carry. However, to provide some buffer for additional appliances, a 40 amp EV charger would require a 50 amp circuit breaker. This increase may add additional costs to your charger install if you require an electrician to upgrade your circuit. 

How Many Amps Does My EV and Charger Need?

While the amount of amps your EV may need differs depending on the vehicle, most can use both 32 and 40 amps without issue. To determine the exact number of amps your vehicle can accept, consult your vehicle’s manual.

If you’ve been looking to upgrade your home’s EV charging station or begin building one, our iEVSE Home unit provides a fast, reliable charge alongside Wi-Fi capabilities and control via app integration. Learn more about our latest EVSE.

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