How Many Amps Does Your Home Charging Station Really Need?
There are a lot of factors to consider when shopping for home EV charging equipment for your electric vehicle. You certainly want to make sure you’re buying a unit from a reputable company, that the unit is safety certified, has a good warranty, and is built to last many years.
However, one of the most important considerations is: How powerful of a charging station do you need? Most battery-electric vehicles (BEVs) available today can accept between 40 to 48-amps while charging from a level 2, 240-volt source. However, there are charging stations available today that can deliver more power, and some that can deliver far less, so deciding how many amps you need for your EV charger might seem a little confusing.
There are four main questions you should consider before purchasing your home EV charging equipment.
How much power can your EV accept?
Electric vehicles are limited to accepting a certain amount of electricity which will be listed in either amperage (amps) or kilowatt (kW). All EVs have onboard chargers, which convert the electricity they receive in the form of alternating current (AC) to direct current (DC) which is how it is stored in the vehicle’s battery.
The power of the onboard charger dictates how much AC power the vehicle can accept. Some EVs have more powerful onboard chargers than others, and they range in power from 16-amps (3.7 kW) up to 80-amps (19.2kW). Therefore, the first thing you need to consider is how much power can your EV accept.
How many miles do you usually drive?
Most Americans drive about 40 miles per day. With home EV charging, you only need to replenish the miles you drove that day because you can plug in every night when you arrive home. Therefore, it’s a good idea to know what your daily and weekly driving needs are, because you can probably get by just fine with a home charger that delivers much less power than your EV is capable of accepting.
If you do use a lower-powered home charger and occasionally need more range for a long trip, you can access public DC fast chargers to rapidly charge up for the long drive.
How much power is available at your home?
Your home has a limited supply of electricity, and you may not have enough available power to install a high-powered dedicated circuit for the EV charger without an expensive service upgrade.
You should always have an electrician perform a load calculation of your service before purchasing your EV, so you know if you can install a home charger, and if so, what is the maximum amperage it can deliver.
Comparing Costs of Different KW EV Chargers
When you receive quotes to install your home EV charger, the price should include supply and installation costs, which means you are paying for the charging unit and the labour required to fit the station ready for use.
Rapid EV chargers cost more than slower, more economical models. However, the labour costs will normally be around 20% of the charger cost – the more complex the electrical components, the longer it will take to fit.
There are also various types of EV chargers, each of which is suitable for a different property type and intended use.
I’m Callum, a complete Electric Vehicle and Sustainable Housing fanatic. Go Green!
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Home EV installers usually recommend a smaller 7kW or 22kW charger as an appropriate charging unit for a private property, although you can certainly install a Rapid charger at a workplace or shared charging facility to allow super-fast charging.
Additional Costs Associated With a 50KW Charger Installation
It costs more to install a fast or Rapid charger because an EV charging unit classed as a slow level one charger can work with any standard power supply. They use 120-volt electricity, so connecting to your home electrical system is simple.
Fast chargers (level two) need a bigger 240-volt power supply, which is why they are primarily used at business premises rather than residential accommodation.
If your system is suitable for this level of power output, an electrician will need to carry out additional work to fit circuit breakers, replace your home consumer unit or install a new isolated circuit solely to power the EV charger.
Cables are linked to the fuse box but are only used to run the charger, insulating the rest of your electrical cabling from potential damage.
Factors in the Cost of Fitting a 50KW Charger
The charging output is one of the most significant cost factors when deciding which EV charger to install. Costs of buying the unit itself can vary considerably from a small 3kW home charger, which is multiple times lower than a Rapid 50kW charger.
Your installation contractor will also normally ask to schedule a site visit to help them ascertain other measurements and elements of the installation work that will affect the price:
- Longer charging cables add around £10 per metre to your EV charger installation quote, as most suppliers provide standard-length cables.
- Fitting a charging port inside a garage may incur additional costs in labour and materials to fit the charger on an internal wall and make good the finish.
- Wireless connectivity, which allows you to manage your EV charger through a mobile app, can add approximately £40 to £150 to the cost of the charging unit.
- Replacing your consumer unit or adding extra circuit breakers to accommodate a Rapid charger will increase your quote by around £350.
Another potential cost element is an earthing system, which is necessary when there is a risk that faulty electrical circuits will cause damage to your system and pose a possible safety hazard.
On average, a set of grounding rods to protect your system and property can add a further cost of £300.
Terms and Conditions
Our EV chargepoint installations are grouped into three categories.
They consider different factors that help us estimate how complex the installation is going to be:
- Where do you want your charger to be fitted?
- How long will it take to run a cable from your main fuse box to your charger?
- Will we need to drill through any walls?
A standard installation is included in the price of your charger. But if the installation is more complex and our engineers will need to spend more time at your home, it’ll cost a bit more.
Every home is different and you might want something more complex. For example, fixing your chargepoint to a pole or hiding cables under floorboards. In these cases, we’ll prepare a custom quote for you.
How is the cost of an EV charger installation calculated?
Every home is different, and every customer has their own preferred setup, so it makes sense that every charger installation is unique.
There are a number of questions to consider when installing your EV charger, from where you want the chargepoint to be, how you want it to look, and where your fuse box is situated. So what kind of things do we take into account when giving you a quote?
- Does your charger of choice have a tethered lead (attached to the chargepoint) or do you want an untethered charger?
- How long does the cable that runs from the fuse box to the chargepoint need to be?
- Where do you want the charger to be installed?
- Aesthetically, do you want the cable hidden where it runs along the wall inside your house,
- Do you want your cable to run underground outside your house?
We’ll be able to work out some of this information such as whether the electricity supply coming into the house is suitable for a car charger, or whether the fuse box might need an additional fuse to accommodate the EV charger.
At Octopus we can be pretty flexible when it comes to meeting your needs, but as a rule of thumb the longer the installation takes us the higher the overall install cost will be.
How much does it cost to power an electric car charger?
When you get your monthly electric bill, you only get to see the total amount you’re charged, not how much each appliance contributes to your final bill. Based on a wattage of 7,200 W for electric car chargers (amounting to 408 kWh/month if you drive your car like an average person does) and using state average electricity rates, here’s how the cost to run an electric car pans out over the course of a month and a year:
Monthly and yearly costs to run an electric car by state
At face value, that can look like a seriously expensive investment. However, it’s vital to remember that when you own and charge an EV, you won’t have to pay for gas anymore. Considering the average American pays well over 450,500 for gas per year, electric vehicles will almost always save you money on fuel.
Looking to offset your electric bills (and the energy these appliances use) with solar? When you sign up (for free!) on the EnergySage Marketplace, you can compare solar quotes from high-quality, local solar installers. Make sure to keep in mind your current and future electricity usage, and talk about how that could change with your installer for the most accurate quotes.
Calculate how much energy your own electric car uses
All electric vehicles have kWh/100 mile ratings – this is the amount of electricity they use per 100 miles driven. To calculate how much electricity your individual car model might use, first convert that rating into a per mile number by dividing by 100. That’s how we got our 0.35 kWh per mile number above.
Once you have a per-mile electricity usage figure, all you need to do is multiply that number by your estimated monthly or yearly mileage, and then multiply the result by your local electricity rate.
See what electricity costs near you
Curious how much electricity costs near you? Click on your state to learn more:
Arkansas Arizona California Colorado Connecticut Washington D.C. Florida Georgia Iowa Idaho Illinois Indiana
Louisiana Massachusetts Maryland Maine Michigan Minnesota Montana North Carolina New Hampshire New Jersey New Mexico Nevada
New York Ohio Oregon Pennsylvania Rhode Island South Carolina Texas Utah Virginia Washington Wisconsin
Frequently asked questions about powering an electric car
If you’re on a time-of-use (TOU) rate plan, you are charged different amounts for electricity throughout the day. In general, it’s cheaper to charge an EV during “off-peak” hours, which are usually overnight.
Home batteries can be capable of powering an electric car, but you’ll likely need more than one: most lithium-ion batteries like the Tesla Powerwall or Generac PWRcell have a power rating of 4 to 5 kW or higher, and 10 kWh of usable capacity. Electric cars use about 7.2 kW (0.1 kW) of power at any one time, meaning a few batteries together may be suitable for charging your electric car.
Average electric car chargers pull about 7,200 W of electricity to stay powered. On average, solar panels are rated at around 350 W, meaning you can power a Level 2 EV charger with around 20 solar panels.
Things To Consider Before Installing A Home Charger
There are several things that you should consider before you have a home charger installed. You may have to factor these into the cost of your home charger installation, so it is good to be aware of them before you decide to go ahead.
- Is your fuse box suitable? You may have to upgrade or replace your fuse box to cope with the additional electricity consumption if yours is particularly old.
- How safe is your driveway? You may want to consider lighting and security cameras by your home charger to ensure that your EV doesn’t become subject to theft or damage since they are expensive.
- Do you need to buy an additional Rapid-charge cable? These can come in handy when you’re away from your home charger.
How Do I Install an Electric Car Charger at Home?
The installation process can take between 3-6 weeks. but much of this is taken up with paperwork. Installers must complete a range of background safety checks and get permission from local grid operators before installing any charger. This is to ensure it is safe to install an electric car charger at your house.
From a consumer point of view, the installation process is actually very simple:
- Choose a provider. There are plenty of options, so make sure you find the best one for you before you begin.
- Fill out a form.
- A quick video call with an engineer to discuss the technical details of your installation. This may be an optional step.
- You will then be given an installation date. You need to be at your house during this process. Make sure you can work from home on this day or rearrange any plans you may have. A charging point installation takes between 2-4 hours. and the technician will also show you how it works while they’re there.
When you choose an approved installer, they will fill out the paperwork to do with securing the OLEZ Grant.
Read
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A home charger may be cheaper to use than public charging points, but by how much? And is the saving worth it when you consider the benefits of Rapid and Ultra-Rapid charging points? Find out how much it costs to charge an electric car in the UK here.
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