32 amp vs 40 amp EV Charger: Which One is the Better Choice?

When you start driving an electric vehicle (EV) one of the first things you’ll want to consider is an EV charging station. A home Level 2 charger is convenient and safe – it’s the ideal way to charge your car. Going to the public charging station isn’t convenient or practical for most EV drivers. 

Shopping for the correct EV charger can be confusing since there isn’t much information available regarding EV charging equipment and their relation to amps. When you start seriously looking at chargers you may notice that most are marked as 32 amp or 40 amp. Of course, there are some EV chargers with lower or higher amps, but 32 amp and 40 amp chargers are some of the most popular.  One of the questions that may arise is what are the differences between amps in EV chargers? Are higher or lower amps better? In this 32 amp vs 40 amp charger article we’ll show you the differences so you can decide which is best for your electric car.

What are amps?

The word amp is short for ampere, which is a standard of measurement that is used to measure electrical current. Current is the rate or speed at which electrons flow through a conductor. A 32 amp EV charger will have a lower constant rate of electrical current than a 40 amp EV charger does.

Does higher amps mean more power?

Higher amps mean longer runtime. You can receive the same amount of voltage from a 32 amp EV charger as you would a 40 amp charger. Amperages indicate the maximum time a device can run before it overheats. This means the higher the voltage, the more efficient the device is. It also means the more amps an EV charging station has, the more electricity it can deliver to your EV at one time. 

Your home only has a certain number of amps that it can distribute between all the devices at one time. If you exceed the capacity of amps, which is usually between 100 and 200 amps for the average homeowner, you will notice power decreasing to your devices and eventually the circuit breaker flipping. An electrician would be able to tell you how many amps you have available and if you would need a circuit panel upgrade to accommodate more amperages. 

32 amp vs 40 amp EV charger

Before you make any decisions about how many amperages you’ll want your EV charger to have you’ll have to look at the maximum power your EV can receive. Most EVs can take in 32 amps, but not all can accept 40 amps.

In general, a 32 amp charger delivers 7.7 kW of electricity, a 40 amp charger delivers 9.6 kW of electricity, and a 48 amp charger delivers 11.5 kW of electricity. 

You can see what your EV acceptance rate is to determine which EV charger amperage is best for you. For example, if your EV has an acceptance rate of 7.7 kW the power delivery it can accept is 32 amps. If you were to charge with a 40 amp EV charger it will draw about the same amount of power as it did at 32 amps and there would be no difference. If your EV kW acceptance rate is higher than 7.7 kW then it would be able to charge faster with a 40 amp charger. 

You would also have to look at how your home circuits are rated. The National Electric Code (NEC), which is the standard for safe electrical wiring and equipment in the US that all electricians should follow, requires an electrical circuit to be rated for 25% greater amperage than your electric car charger output. For example, if you opt for a 40 amp charger it needs to be installed on a circuit breaker that is rated for at least 50 amps.  If you choose a 32 amp charger it would be required to be installed on a 40 amp circuit. 

If you don’t have the properly rated circuit at your home before the installation that doesn’t mean you can’t upgrade, you would just need the services of an electrician. Doing so would incur more charges on your installation.

Any advantage to getting a 40 amp charger vs a 32 amp?

There are pros and cons to each charger. The differences between the two are not major.

A 40 amp charger will more than likely have a longer lifespan than a 32 amp charger. A 40 amp charger should have more durable electrical components to withstand the higher electrical current. If you compare a 40 amp charger to a 32 amp charger you will notice the cord that supplies the electricity from the charger to the EV will be much thicker and more durable. The thicker an EV charging cord is the more it will be able to withstand daily abuse and extreme winter weather. 

Yet, charging at a lower amperage is better for the health of your EV lithium-ion battery. With a 32 amp charger, the battery won’t get as hot and you’ll be able to retain efficiency better when compared with a 40 amp charger. 

A 40 amp EV charger also helps you future-proof. In later years EVs will have larger capacities and kW acceptance rates. Having a more robust charger will mean not having to buy a new one with your next EV. 

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You will see faster charging speeds with a 40 amp charger as opposed to a 40 amp charger but not by much. A 32 amp charger will take about 8-13 hours to fully charge an EV battery from empty, while a 40 amp charger will do it in 6.5-10.5 hours depending on the size of your battery. This time difference may not be a big deal for an EV owner that plans to charge overnight. Most EV drivers use their home chargers for overnight charges.

What are the different types of EV chargers?

Home EV charging stations are almost always Level 2 charging stations. Level 2 EV chargers have the perfect balance of power and speed for an EV driver. A Level 1 charger is too slow and a Level 3 or DC fast charging station requires too much electricity and isn’t necessary for a typical home overnight charge.

A Level 1 EV charger comes standard with an electric vehicle purchase and will have an SAE J1772 or J plug. The SAE J1772 is the standard for electrical vehicle connectors in North America. It is universal for all EVs except for Teslas. Teslas will need an adaptor to plug into an SAE J1772 connector.

A Level 1 charging station plugs into a standard household 120-volt outlet. A Level 1 charger is very slow and is notorious for taking days to fully charge an EV battery. A Level 1 charging station is not practical for daily EV drivers. If you only plan to take out your EV once or twice a month then a Level 1 charger may suffice.

A Level 2 EV charger is up to 15 times faster than a Level 1 charger and adds 15-75 miles of range per hour of charge. Your charging time will depend on factors like the outside temperature and your EV battery capacity. 

Level 2 charging stations not only provide powerful charging, but they are reliable and convenient. A Level 2 charger requires a 240-volt outlet. Most homeowners won’t have a spare 240-volt outlet in their garage and will need to find an electrician to install their home charger for them. You can choose to have a permanent charger or portable charger installation.

A Level 3 electric car charger is better known as a DC fast charger. A DC or direct current fast charging station can charge 80% of an EV battery in as quickly as 10 minutes. DC fast chargers are found at public charging station sites. They require too many electrical infrastructure upgrades and electricity to be a feasible option for an EV owner.

Tesla charging amps

Tesla charging amps will vary by which Tesla model you own. A Tesla Model 3 rear-wheel drive has a 32-amp acceptance rate. The Model 3 Performance and Long Range models, Tesla Model S, Tesla Model X, and Tesla Model Y have 40 amps. 

The Tesla Model 3 rear-wheel drive will require a 40 amp circuit for charging, while the other models will require a 60 amp circuit. 

You can charge your Tesla with third-party chargers or the Tesla charger called the Tesla Wall Connector. To charge with third-party EV chargers you will need to purchase an adaptor from Tesla. The recommended circuit amperage for a Tesla Wall Connector is 40-100 amp.

How do I get powerful Level 2 charging at home?

If you want a convenient and reliable home Level 2 charger at home you’ll need to connect with an electrician that can help you install a 240-volt outlet for a portable charger or to hardwire a 240-volt circuit for a permanent home charger. The most hassle- and stress-free way to start charging your EV at home is to connect with WattLogic. WattLogic will help you find the perfect EV charger for your electric vehicle, apply for money-saving rebates on your behalf, and manage the installation. Get a quote from WattLogic to get started on installing a powerful Level 2 charger at your home!