How to Bring the SuperCharger Home
Want to learn how to bring a Tesla supercharger to your home? Here are the instructions you need to start fast charging where you live. Be warned, it's expensive!
A Tesla Supercharger station allows you to charge 80% of your battery in just 40 minutes, which is a truly amazing achievement in charging technology. So, why not take this capability home with you? What if you were able to take this high speed and high capacity charge to your garage or curbside? You would be able to charge at lightning fast speeds without waiting in line. You’d be the envy of the Tesla community. Imagine saying goodbye to those low level chargers and long wait times by charging at 200kW from your at-home charge stations.
So what exactly is a supercharger? Well, the Tesla definition of a supercharger is a 480V high-speed charger developed to create a network of public charging stations. This network encourages people to buy a Tesla because it makes their superchargers as ubiquitous as gas stations. As a driver, this takes away the anxiety and fear of having a dead battery, also known as “range anxiety.”
Tesla offers multiple supercharger plans to use at these stations: the lifetime, 100 to 40kWh per year, and single credit plan. You may also pay on a per use basis which is typically billed based on time spent charging. These plans can cost you up to $1.30 per minute, or around $0.30 per kWh. If you stay past your charge, you’ll also be billed an idle fee of $1.00 per minute when the station is at capacity.1
This is more than double what the average Tesla driver in the United States spends, which is $0.13 based on our research here at Optiwatt. If you aren't familiar, we are a free app that tracks exact home charging costs for Tesla owners, so check us out if interested!
PARTS NEEDED TO INSTALL A SUPERCHARGER AT HOME
So, what would it take to build your own system? Tesla superchargers have a top power of 250kW and require a 480V three phase line, which is well outside the standard of residential charging. This is a lot of power, so could you really get a license for it? First, you will need a step-up transformer to convert your residential 240V single phase line into a three phase 480V line. This 480V is a dangerous to install, and must be approved by city officials, energy agencies, and often installed by high-grade electricians.
After you get your transformer, you will need to get a metering transformer cabinet, electrical meter, correction capacitor, high capacity breaker box, circuit breakers, and an emergency shut-off switch that can handle 480V and the proper kVA for this equipment.
Finding the correct kilovolt-amps (kVA)
For our equipment, we have 480V and 250kW, but we need to know how much kVA that equates to.
Here is our equation, and we are able to solve for amps. Our result comes out to 521.15 amps, and now we can solve for our kVA. In the equation below, we plugged in our volts, amps, and 1.732 for our three phase line, resulting in a kVA of 433.26. We suggest checking your result with an amps-to-kVA calculator to verify that you solved it correctly.3
Unfortunately, transformer current and power ratings aren't very numerous. High-end three phase electric transformers are typically rated for 100A, 200A, 300A, and so on. For our 433.26kVA, we would want a transformer rated for 600kVA or 800kVA to be safe.
You can find transformers with a quick Google search, 4 and see that transformers rated for 480V, 433.26 kVA, and 521.13A run upwards of $30,000 to $40,000. The next step is to get a metering transformer cabinet, which is an energy company requirement when using high powered lines. These cabinets cost about $3,500 to $4,000 each, and you will need to attach an electric meter to the side of the cabinet which will cost another $400 to $600.
The Breaker Box
Next, we need a breaker box that is rated for 480V and can handle a full load from our three phase line. This is just like your breaker box at home, but 10 times larger and sure to flip off when an electrical surge occurs. This prevents your whole system from being destroyed. A breaker box of this size is anywhere from $2,500 to $5,500, with circuit breakers needing to be installed too. The actual breakers run about $5,000 to $8,600. These industrial rated breakers are able to handle the current and waste heat that is typical of such a high voltage system. Platt, for example, is one company that sells breaker boxes and circuit breakers that meet the standards of this high voltage project.5
The Correction Capacitor
A correction capacitor is also needed in our breaker box. Why? It reduces extra consumption of electricity in the system and helps with the transformer load so it isn't over-strained. These range in cost from $1,500 to $5,000.6
The Safety Switch
Our next small ticket item is a safety switch, which allows you to shut off the power if anything goes awry. These are required in all high voltage systems, and are necessary to get your SuperCharger station approved. These switches run about $3,100 to $6,300 for the 600A rating. The circuit box and capacitor will be next to each other within your private power system layout. National fire laws require that safety switches be located at least 50 ft from circuit breaker boxes and transformers, so that you can shut down power in a safe manner if the safety mechanisms in the transformers fail and the breaker box is overloaded. The switch will most likely be placed at the entrance to the area that houses the breaker box and transformer. The entire electrical hub can be placed underground or above ground, but either choice will need to be properly labeled with “high voltage” signage.
Now that we have all the parts to power a supercharger, we are ready to start installing right? Not quite. We are going to need permits for this project as well. Permits have different requirements depending on the state and city in which you live. In California, if you want to do electrical work, you have to abide by energy conservation requirements for your permit.7 Extra fees apply to this specific type of project, because we need a trench for your new electrical line after a survey is completed that highlights the current line locations. Keep in mind that if you start building or installing your equipment without your permits approved, you can be fined for each permit violation, which gets expensive quickly. Make sure every form is approved. Upon applying for your permits, the city will provide you with a total cost adjustment for the install, and will recommend electricians for the job.
Here are the permits you must have in order to start your project within the state of California.
- Zoning Plan Check
This makes sure your area is zoned properly for your build.
- Erosion Control Preliminary Site Inspection
This covers the cost of sending someone out to do a geological and environmental survey of your area. They will check for hazards within the property.
- Building Plan Check
This makes sure the project meets all building codes, and you match up with energy conservation requirements.
- Building Permit Processing
This cost is to send sets of plans out for review to necessary parties. From here, the city communicates all fees tied to the project and makes two copies of the project file. One is kept on hand, and the other copy is stored on site during construction.
- Public Works (Drainage)
This fee pays someone to check your plans for any water drainage issues on your property. The public works official will also make sure that your project installs proper drains and doesn’t retain water incorrectly.
- County Fire Plan Check
This fee covers an overview assessment to see if your project needs a sprinkler system installed.
- Affordable Housing Impact Fee
This fee determines the square footage of your new project, and how that might impact affordable housing in your area.
- Other Fees
There is a 6% fee that goes towards the maintenance and general update required of all building permits. The average sum of these permits is $1,314 to $7,500, and that doesn't include extra fees.8
- Extra Fees
Extra fees can be as low as $1,849, or as high as $12,698, all depending on how much wire you plan for and how long it takes to review. Make sure you get your permits handled properly, and do not start work without the permits or you will pay $5,000 per violation as a punishment for starting without the proper clearance.9
Hiring a team to wire in your new SuperCharger system is a state requirement. This is because a licensed electrician is the only person who has been acceptably trained to handle a 480V line upgrade from a 240V power line. The job will be done by a master electrician and his team. They will install all necessary equipment, including the step-up transformer, metering transformer cabinet, breaker box, capacitor, emergency shut-off switch, and SuperCharger. Due to the large amounts of equipment, the team will consist of a foreman,10 master electrician, journeymen, and an apprentice electrician. The cost of each hire is $40/hr for the apprentice, $60/hr for the two journeymen, $100/hr for the master electrician, and $60/hr for the foreman.11 If everything is delivered on time and there are no additional delays, you can expect the install to take about two weeks. The permit approval is needed before work can begin, which can take 50 to 100 days.12 The labor costs add up to around $25,600 for the entire team during the installation period. Keep in mind that if your electrician works 10 hour days or during weekends, there will be an overtime charge added to the labor costs because electrical unions have stipulated this in their contracts for their employees. 13
250kW chargers are limited, because there are not many on the market. BTC Power offers a 50kW to 200kW charger, with the 50kW charger costing $5,000 to $10,000. The 100 to 200kW model costs $26,102 to $49,504, which would mean filling your battery takes between 30 mins and 1.5 hrs depending on your battery capacity.
Finally, all the work on the electrical equipment has been finished, the final review from the city has been approved, and your “at-home supercharger” is finished. At this point, your total cost is between $81,804 and $165,302. Yes, this is a small fortune spent to install an at-home supercharger so that you don't have to share, but you will surely become the envy of the Tesla community.
With this outrageous price tag and long installation process, there are more reasonably priced home “SuperCharger” alternatives. The Bosch EV2000, which offers 25kW for $11,348, is single phase at 240V. This is much more practical and cost effective than the 200kW SuperCharger station. The Bosch can be wired into a 240V single phase line and power up your battery in between 3 and 4 hours. While this is no SuperCharge, it certainly is more gentle on your wallet.14
After all that, let's face it, it’s downright impractical to build your own supercharger in 2020, but that doesn’t mean it won't be possible in the next 5 to 10 years. Tesla has grown their SuperCharger network by about 1,000 stations between 2014 and 2020, and there is no reason to believe this trend won’t continue. Perhaps at some point, Tesla will make it easier to bring that technology into the residential garage.
For now, the best alternative is the level two 240V Bosch EV2000. It's $153,954 cheaper than trying to build a SuperCharger with complete electrical hookups, and you don't have to pay an electrician $25,600. Plus, the at-home station manufacturers make several models that integrate with your Tesla through an adapter. The level two systems make it a lot easier to charge at home, and don't consume outrageous amounts of electricity like a SuperCharger. Check out ClipperCreek, JuiceBox, Bosch, AxFast, Lectron, Hubbell, Chargepoint, and even Tesla with their new third generation charger.15