What Current Is Required To Charge An Electric Car?


Electric cars are complex electric machines that can cost a pretty penny so it would be useful to know the right way to plug them in and charge them up. There are two types of current primarily used with electricity: alternating current, or AC, and direct current, or DC. Depending on the type of machine you are dealing with, it can be very important to know if you should be using direct current or alternating current as some machines are built specifically for one or the other. 

What current is required to charge an electric car? Using direct current to charge your electric car is generally faster but either alternating current or direct current can be used to charge your electric car. A minimum of 15 amps of current is required, but that will likely take several days. Fast charging stations use 500 amps and at-home chargers generally use around 40 amps.

Electric cars come equipped with the necessary components to convert alternating current electricity to direct current electricity if need be, so you don’t have to worry about blowing up your car by using the wrong current. Each car model and manufacturer is a little different though, so it is always a good idea to make sure you are caught up on the certain requirements of your specific electric car to avoid any problems with your car’s battery or other systems. 

What Current Is Required To Charge An EV?

As I just stated, direct current is used in most car batteries but you have the convenience to use both alternating current and direct current to charge your electric vehicle. Electric vehicles have onboard chargers, OBCs, that give them the ability to convert alternating current to direct current that the car can use. Car manufacturers have made these vehicles adaptable to the different places you might be with your electric car, so you won’t have to worry too much about not being able to charge your electric vehicle. 

Direct current is used in most fast charges that you find at gas stations or offices. Alternating current is what is used in most residential houses. When on the road, you will be most likely using direct current and when plugging in at home you will be using alternating current. Direct current is used in fast chargers because the electric vehicle doesn’t have to take the time to convert the current.

The OBCs all have a speed at which they can convert. Say you have an at-home charger that can charge your electric vehicle at 20kW, but your OBC can only convert the alternating current to direct current at 8 kW. Even though your at-home charger can pump 20 kW into your car, it does no good because the OBC can only handle 8kW at a time so it takes longer to charge the battery. 

As far as amperage, your electric car will require a minimum of 15 amps to start charging. If you go this route, it will take several days to reach the desired 80% charge. Generally, fast charging stations use about 500 amps and can charge your electric car in less than an hour. At-home chargers generally use about 40 amps and that will give you a full charge in a matter of a few hours.

Do Different Manufacturers Have Different Current Requirements?

Though all electric vehicles use direct current in car batteries as a standard, not all manufacturers make the vehicles able to handle all types of charging. Most at-home chargers you use to charge your car are known as Level 1 charging. Level 1 charging is usually done at 120V. Level 2 charging is done at 240V and is usually what you can find at many public places and at offices.

Level 1 and level 2 both use alternating current charging. Level 1 chargers are going to be the slowest chargers, only providing about 3.5-6.5 miles worth of electricity per hour. Level 2 is going to give more than double this, offering anywhere from 14 to 35 miles worth of charge per hour according to calevip.org

Direct current can be found in the more rare Level 3 chargers. These chargers have the incredible ability to charge most electric cars in the short time of 20 minutes to 1 hour of charging, depending on the capacity of your car’s battery. Level 3 chargers pump electricity into your car’s battery at an incredible rate of 43kW to 100+kW. These chargers usually require manufacturer-specific plugs to use. Some manufacturers don’t even construct their vehicles to be able to handle this rate of charging, so make sure to check what your car can handle before using one of these chargers. 

Is There Such A Thing As Too Much Current?

Even though the greater the current usually means the faster the rate of charge for your vehicles, I would have to say yes, there is definitely such a thing as too much current. As stated in the section above about level 3 chargers, some cars aren’t even made to handle the amount of current that level 3 chargers pump into your car. Batteries are only made to handle so much current and if you try to charge your battery faster than it can handle, it could be detrimental to your vehicle. 

There is a warning that comes with Level 3 chargers even for those vehicles that are able to use them. The amount of current that the Level 3 charger pumps into your battery at one time can actually decrease the lifetime of your battery. Charging your battery that fast can cause it to deteriorate more quickly. This isn’t to scare you into not using Level 3 chargers because all batteries deteriorate and decrease in efficiency over time, it is inevitable. Level 3 chargers just cause this to happen a little faster than usual, due to the rate at which it puts electricity into your battery. 

It is suggested that you actually switch your battery every 3 years or so to keep it in tip-top shape and to avoid any dangers that may occur, via kia.com. If you are taking good care of your battery and car, your battery should easily last to at least five years. There are some companies like Tesla that actually guarantee their batteries out to eight years. All in all, when you are in a rush or on a long road trip it might not be such a bad thing to use a Level 3 charger but it probably wouldn’t be the best idea to use one every single day. 

What Size Of Breaker Is Required On Your Home’s Breaker Box To Charge An EV?

The size breaker required on your home’s breaker box to install a charger for your electric car is going to depend on the amperage and size of the charger you want to install. According to the National Electric Code, in the United States, an electrical circuit has to be rated for a 25% greater amperage than your charger’s output. Say you were to install a charger that does 40-amps, you are going to want at least a 50-amp breaker hooked up with your charger. This would be for a Level 2 240V charger. 

Different chargers always have different amperage. Some are lower than 40 amps and some are greater than 40 amps. So make sure you aren’t spending extra money on a big breaker you don’t need, or be aware of buying too small of a breaker and end up overloading your system. There are some electric vehicle chargers that are available for purchase that have adjustable amperages. So you can adjust it to what your house can handle.  

Before you look into buying an electric car charger, you are going to want to make sure your home’s system can handle it. All you need to do is open up your breaker panel and see if there are any unused breakers or room for any new ones. If there aren’t, then you may need an upgrade before you can install a charger. If you are looking to install an electric vehicle charger on your own, be sure to really do your research and know what you are doing so you don’t overload your home’s system. It would always be a good idea to double-check things with an electrician if you are wanting to install an electric car charging at home.  

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