If you're about to get an electric vehicle and are concerned about getting your EV charging situation sorted out at home without getting seriously charged — as in digging a big hole in your wallet — you're reading the right post.
I'll explain, via my own experience, how to get your new vehicle's "tank" filled and avoid those over-the-top electrical upgrade estimates.
While I wrote this based mostly on my two-plus years of experience with my 2021 Model Y Long Range, most of what I'm mentioning here applies to any EV. It's collective wisdom from my friends and neighbors with different EV types.
To cut to the chase: Getting your car charged is generally more straightforward than you might think, and it's much better than going to a gas station. If you live in a home with a garage (that has an electrical outlet) or an accessible outdoor socket, you're already ready to leap. Think of your EV as another large appliance.
But there's more to getting a car charged than plugging it in. Let's start with the simple math of charging a vehicle.
Dong's note: I first published this piece on February 8, 2023, and updated it on April 16, 2023, to add relevant, up-to-date information.
EV charging: The general math of getting a car charged
Charging a battery is like filling a tank with water (or any type of liquid.)
The tank is the battery, and the water flow (pressure + pipe size) is the incoming electricity determined by Ampere (A) and Voltage (V). Combining the two, we have Wattage (W), which is, in this case, the tank's volume or power flow.
Getting a bit nerdy: Voltage vs. Ampere vs. Wattage
It's easier to understand electricity if you think of it as the water flowing through a pipe from one container to another.
- Voltage (V): The volume of electricity or the size of the potential force that sends power over the wire. (It's the amount of water with built-up pressure in the pipe before you open the valve.)
- Ampere (A): The size of the energy flow. (It's the force of the water flow as the result of the pipe size and the volume at the source.)
- Wattage (W): The consumption or capacity of containers at either end of the electricity flow between the two at any given time. (It's the tank size or the amount of water used.)
The higher the amperes and voltage, the faster electricity can move from one place to another (charging speed). The more wattage, the more power is stored, used, or delivered.
Here's the relationship between these three:
V * A = W
You generally find wattage in two measurements:
- Kilowattage (kW): It's the metric way to call 1000W. It generally indicates the flow rate of electricity.
- Kilowatt-hour (kWh): The energy consumed, delivered, or accumulated over one hour. It indicates the amount of energy.
A car's battery is measured in kWh. The higher the number, the more energy it can hold.
A 110V 15A outlet typically has a capacity of 110 * 15 = 1650 W or 1.65 kW. Specifically, if you plug your car into that socket, it can get up to 1.65 kW per hour — often slightly less.
When the flow is constant, the rate of water entering the receiving tank is the same. So, how long it takes to fill a tank depends on its size.
After that, how long that full tank lasts depends on the usage or efficiency. Generally, the flow of electricity is always constant.
My Tesla Model Y 2021's battery has a capacity of 75 kWh. Per the EPA estimate — which is massively exaggerated — the car has a range of up to 324 miles on a full charge or 4.3 miles per kWh.
With that range, when plugged into a 120V (which caps at 15 A) socket, its charge rate is 5 miles per hour.
The actual real-world distance you can drive per kWh varies greatly depending on speed, load, wind, terrain, your belief in Elon Musk's nonsense, and so on. But the rate at which electricity flows into the battery remains the same, which, in this case, is about 1.5 kW per hour (give or take).
This electric flow rate applies to all Tesla EVs that use the same battery technology. But on a Model S, when plugged into the same 120V socket, this rate will translate into roughly 3 EPA miles per hour — this model requires more energy to move.
The point is this: You can increase this charging rate by using higher amps (and voltage). That's the case for all EVs.
Typically you need a 240V socket if you want more than 15A. And, in the US, that means you need to do some serious electrical upgrades.
Or do you?
EV charging: It’s different from the pump
More than two years ago, in preparation for my Model Y's arrival, I had difficulty figuring out our electricity situation at home.
Chances are some of you are feeling the same right now when anticipating the delivery of your beloved vehicle or mulling over the idea of getting one.
Doing my search and listening to the advice of online EV "experts" — there are many of them these days — I got quotes from reputable electricians ranging between $5,000 to $15,000 in electrical wiring and breaker upgrades, depending on the scope of the work.
That's not to mention the required permit and inevitable disruption — a home would have no electricity for at least a day during the retrofit.
It's "all about the amps," and it made sense. As mentioned above, the standard 120V socket in the US can push out a maximum real-world rate of 15 amps — often lower for safety reasons.
A Tesla Wall Charger, for example, needs a 60 amps breaker at 240V to deliver the fastest home charging speed. My Model Y would get up to 42 miles (68 km) per hour of charging from it, or eight times the charging rate compared to when plugged into the existing 110V socket.
And that's all true — we need higher amps to deliver faster charging, which generally requires better wiring and breaker upgrades. The electricians didn't lie.
But in hindsight, it was only because I was looking at the whole thing from the mindset of a person who had always driven a car with an internal combustion engine (ICE). And so did the electricians. None of those giving me the quotes had an EV.
The real question is this: How fast do you need to charge?
EV charging vs. filling the gas tank: You’ve got all night
With an ICE car, we "feel the pain at the pump," as they often say during high gas prizes. And since we don't (want to) spend much time there, it's great that the tank only needs a few minutes to fill up.
And then what? You drive the car home, put it in the garage, and there it sits, doing nothing for hours.
With an EV, on the other hand, you can get the tank filled (slowly) whenever you're home or even when the car is not driven. So, in most cases, fast charging is unnecessary, at least for daily usage. You literally have got all night.
Slow charging is generally better for batteries. Unlike Superchargers that typically require conditioning the battery for optimum charging, you can plug/unplug the car arbitrarily with home charging with no additional effect on the battery or changing speed.
Take my Model Y, for example. If I plug it in the 120V socket when I get home at 5 PM, by 8 AM the next day, it's obtained enough juice for some additional 60 real-world miles. And that's enough for the day's driving. And on the days I don't drive, I can keep the car plugged in much longer.
Even if you drive a fair bit more than I do daily, the combined charging time over a week of a regular socket is generally good enough.
So again, if you have a garage with a 120V socket or one that you can plug outdoors, you're ready to get an EV as far as charging is concerned. But, sure, a faster charging option doesn't hurt — among other things, it gives us more flexibility.
But how fast is fast?
Check out the three current charging levels below, and I'll talk about how I managed to get my fast-charging solution (for the Model Y) without going overboard and spending thousands of dollars I didn't have.
Level 1 EV Charging: 120V (up to ≈ 15A)
- Electricity: Alternating current (AC).
- To-car connectors: J1772, Tesla.
- Charging rate: 3 to 5 Miles Per Hour (≈ 1.5 kW).
- Applicability: Home or anywhere with a 120V wall socket.
Level 1 charging is the lowest and, in the US, generally means you plug the car directly into a 120V outlet using the car's default (often included) portable charger, technically called electric vehicle service equipment or EVSE.
There are also third-party portable chargers. While varying in design, costs, and possibly quality, all chargers will work with all EVs. It's just a matter of getting the right adapter when necessary.
These "chargers" are essentially power cords. The charging function is inside the EV.
Apart from the 120V socket, most level-1 chargers also work with 240V sockets to deliver faster Level-2 charging speed.
Until April 17, 2022, Tesla included the Mobile Connector with its cars. It's the company's default Level-1 Charger.
Level 2 EV Charging: Up to 240 V (up to ≈ 80A)
- Electricity: Alternating current (AC).
- To-car connectors: J1772, Tesla.
- Charging rate: Up to 80 Miles per Hour (≈ 20 kW).
- Applicability: Home or anywhere with a 240V wall socket or a charging station.
Level-2 charging is the fastest option you can install at home. It requires new wiring.
At the minimum, in the US, you'll need a separate breaker for a 240V outlet, similar to an oven or dryer. Most EVs' portable chargers work with 240V and 120V outlets via interchangeable to-wall adapters.
A charging station, such as the Tesla Wall Charger, requires new wiring. This type of charger must be wired directly into a 240V breaker and won't work with any socket.
Level 2 can deliver between 15A to 80A of electrical flow and give an EV up to 80 miles in an hour of charging through 60 miles/hour is common.
Level 3 EV Charging: At least 400 V
- Electricity: Direct current (DC).
- To-car connectors: Combined Charging System (CCS) and Tesla
- Charging rate: at least 3 miles per minute, up to over a thousand miles per hour.
- Applicability: Public charging station
Level 3 charging equals "gas stations" for EVs — it's the fastest charging option.
For years, Tesla's Superchargers have been the most well-known Level-3 charging, with each charger capable of filling a Tesla's battery from 20% to 80% in 20 minutes, or as fast as 5 minutes, depending on its wattage, which ranges from 75 kW to 250 kW (and even higher.) The higher, the quicker the charging rate.
In the US, most, if not all, non-Tesla Level-3 charging stations use the CCS connector, which encompasses the J1772 connector.
Many non-Tesla DC chargers include a Tesla connector.
Level 3 charging uses direct current (DC) instead of alternating current (AC), like in the case of Levels 1 and 2. Each charger costs tens of thousands of dollars. That's not to mention the electricity cost.
Other than CCS, some Japanese cars also use a new connection called CHAdeMO for Level-3 charging. In the US, a CHAdeMO DC charger often includes a CCS and a Tesla connector.
As you might have noted, all charging options require a to-car connector — the part that goes into your EV's charging port.
In the US, there are two main charging connection standards:
- Tesla proprietary: Supports all three levels of charging using alternating current (AC) or direct current (DC).
- Combined Charging System (CCS): Supports charging level 3 via DC but has built-in support for the AC-only J1772 standard for Level-2 and Level-1 charging.
Only the Tesla connector can fit existing Tesla cars — future ones might have built-in CCS support. For this reason, a converter is generally needed if you want to get your Tesla juiced up at a non-Tesla charging station. Currently, there are two converters in the US, the J1772-to-Tesla and CCS-to-Telsa.
I'm not a huge fan of proprietary connectors — like Apple's Lightning connector — but to be fair, worldwide, the standards for charging connectors are still very fragmented. In Tesla's case, it needed to create a new standard since none existed for EVs.
Since early 2023, Tesla has opened its Supercharging network to non-Tesla EVs (a Tesla-to-CCS adapter is required for existing chargers). Increasingly, many non-Tesla DC chargers include a built-in Tesla connector.
CCS vs. J1772
A car with a CSS charging port supports both J1772 and CCS connectors.
Tesla owners take note: If you have the CCS adapter, you don't need the J1772 adapter anymore.
For home charging, the Tesla-to-J1772 adapter has been available for a long time.
Simple home charging options
For home charging, the portable charger (included with most EVs) is generally enough.
The portable charger of a Tesla is the Mobile Connector. Originally, it's included with a new car for free, but starting April 17, 2022, it's been an accessory you must pay extra for.
In any case, this charger is simply a glorified power adapter — the charging function is inside the vehicle. The point is that you can always buy a third-party portable charger that fits your usage and budget. They all function as power cords.
I'll use my Model Y's Mobile Connector as an example, but other portable charger shares a similar concept.
Though much bigger, the Mobile Connector is similar to a laptop's power adapter — it can handle power input from 110V to 240V and various amps outputs via different to-wall adapters that fit different wall sockets.
And by default, the charger includes the standard adapter head for the region. In the US, that adapter head is the NEMA 5-15, the three-prong plug for any wall socket around your home. In this case, you can plug it right in, just like a phone, and it will charge the car a few miles per hour, as mentioned above.
Using different adapter heads out of the bundle in the above picture, you can charge the car at faster rates, depending on the power output of the fitting socket.
In the US, the best option is the NEMA14-50 — a popular plug for electric ovens or dryers. With it, the Mobile Connector works with a 240V outlet to draw up to 32 amps of power to deliver a filling rate of around 7kWh. (For my Model Y, that's about 30 miles per hour.)
Starting in August 2022, in the US, the Mobile Connector includes the Nema 5-15 and NEMA 14-50 adapters.
The actual amps the car's charger draws depend on the real-time condition when you plug it in, and for Level-2 and Level-1 charging, users generally have control over that. With a Tesla, you can use the mobile app to make the car draw lower amps than available.
So a 240V Level-2 charging option will also allow you to trickle charge the car when you're not in a hurry.
A typical home charging station
In my case, I decided not to do any major breaker upgrade or install the Level-2 Tesla Wall Charger.
Instead, I had a licensed electrician friend install a 240V 40-amp outlet by upgrading an existing line and using the NEMA 14-50 adapter head for my Mobile Connector. All that cost less than $500.
It's important to get this done correctly. I'd recommend using a professional for the job. I did. Also, generally leave the NEMA 14-50 adapter in the socket — it's best not to remove it often.
With the new socket, the Mobile Connector can deliver up to 32 amps and fill my model Y at around 30 miles per hour, or about half of a real level-2 charging station. Still, that's fast enough for a full charge overnight.
I later got a second Mobile Connector, mounted it permanently in the garage as my home charging station, and kept the original with the car.
But that's proven to be already more than enough. Most of the time, I use the Tesla app to tune that down to 20 amps or lower to slow down the charging rate — there's no need to put an unnecessary strain on the wiring.
I find it a fun challenge to make the car have an exactly specific amount of energy before leaving for a trip.
Once in a while, I still plug my car into a 120V socket, especially when traveling, as I'd need to charge from a rental house or a campsite, and that has always been sufficient in most cases.
EVs and energy usage
EVs are considered large appliances in terms of power consumption and should be plugged in as such.
Specifically, you shouldn't charge your car at home during peak hours. Instead, charge them at night when, among other things, the cost of electricity is lower. (The opposite might be more applicable when solar energy becomes more prevalent.)
A fast 240V charging port gives you more flexibility in timing the charge.
So my routine has been to plug the car in and let it do its things when I get home. And I generally set the max charge at 180 miles, about 55% of the battery's capacity, more than my typical day's worth of real-world driving.
And that brings us to some tips on charging your EV.
EV charging: Battery types and best practice
Generally, batteries are at their best when they are not completely empty or full.
In practice, with EVs, that depends on the battery. All EVs use Lithium-ion batteries available in two types differentiated by mainly the materials used for their cathodes.
The first type is nickel-cobalt aluminum (NCA), a.k.a nickel manganese cobalt (NMC), which is expensive but light and can be charged relatively fast.
Generally, NCA batteries have limited charging cycles and should typically be charged at 80% to maintain longevity. It's the type currently used in most existing EVs.
In 2022, a new sub-set of Lithium-ion batteries, lithium-iron-phosphate (LFP), went into production. This type is heavier and takes longer to fast-charge. So it's not ideal for long-range or performance applications.
In return, LFP is less expensive — it doesn't require rare materials like NCA. Most importantly, it has significantly higher charging cycles to last much longer and can be charged regularly to full without degradation, offsetting the shorter range and easing overcharging anxiety compared to NCA.
(by early 2023)
|Most existing EVs
Some high-end future EVs
|Tesla Model 3
(2022 and newer)
Tesla Model Y SR
(2022 and newer)
Most future EVs
|Level-3 Charging Speed
|Home Charging Speed
|Recommended Charge Level
at least once a week)
|up to 3,000 cycles
|Up to 10,000 cycles
|Risk of Fire
The two types of batteries are the same in principle and are differentiated only by the materials used for their cathodes.
So far, only Tesla has used LFP batteries in its fleet, but other car makers will follow suit. LFP batteries are also under further development and optimization to deliver better performance. It might eventually replace NCA in the future.
Generally, in daily usage, it's best to use an EV with a battery between 20% and 80% because of the following reasons:
- You can charge it the fastest. It takes much shorter to fill a battery from 20% to 80% than from 80% to 100%.
- It outputs energy the most efficiently.
- The (NCA) battery itself can last the longest without degrading.
This idea of giving stuff some "breathing room" exists in ICE cars, too. Most gas stations suggest that you don't "top off" the tank, and all mechanics will tell you that letting the car run completely out of gas is a bad idea. Getting stranded aside, running the car till the gas tank is empty means you will let harmful sediments into the engine.
Before you get on an extended trip, it's fine to charge any EV to 100%, and when you're on the road, plan to get it plugged in before the battery gets lower than 10%. On a long drive with multiple legs, it's best to charge the car enough for the next DC charger (with some to spare.)
If you accidentally change the car over a certain level, like 90%, and want to lower it without driving: Keep the car plugged in and lower the charge level, say 80%. The vehicle will discharge during the normal charging hours until the desired level is reached.
No matter which type of battery, don't drive your EV until it's completely out of juice. Unlike ICE cars, EVs need electricity to keep their subsystem running.
Finally, monitoring your car's battery using percentages rather than miles is recommended. The range estimate is so greatly inaccurate and widely exaggerated, especially in Tesla's case, that it's dangerous to count on. But if you use it, discount at least 30% to be safe — more in this post about my Model Y's real-world range.
Be aware of charging schemes
When using a charging station, pick one that bills you by energy, not by how long the car is plugged in. The latter can be ridiculously expensive.
While many venues come with free charging stations, which is great because you'd need to park your car anyway, other places put up time-based low-energy chargers to get high "parking" fees from EV drivers.
The point is, make sure you read the sign or do the math.
It's impossible to talk about EV charging without mentioning Tesla's Level-3 Supercharger network, the most comprehensive charging network worldwide.
In fact, the only reason I get the Model Y (or any Tesla) is because of the company's Superchargers. They make talking road trips possible.
There are two things worth noting about Tesla's supercharging network.
First, it's ubiquitous and super convenient to use:
- When the car's battery is low, its screen will show nearby Supercharging stations on the map, which is much more convenient than Google Maps, which has EV chargers as points of interest.
- Punch in a destination on your car, and the car's navigation will include stops charging station(s) if need be.
- When you pick a charging station, the car automatically optimizes its battery for fast charging.
- Drive the car to a charging station, plug the charging cord into the car, and you're all set.
You can manage the charging (and payment) via the car's touchscreen or the app. But if you don't do anything, the vehicle will be charged at your predetermined level, or enough to get to the next charging station of the trip, based on the car's current rate of consumption and real-time road and weather conditions.
Secondly, a Supercharger station can charge a car fast. Starting at 70kW and can go as high as 250kW, a station can fill my Model Y's battery from 20% to 80% in 30 minutes or under 10 minutes, respectively.
Tesla also has Level-2 Destination Chargers, similar to home chargers, that top at around 60 miles per hour.
Supercharger and cost
The actual price varies from area to area, but generally, on a bad day, the cost to fill my Model Y from 20% to 80% is about $20 — that's easily over 100 real-world miles worth of energy.
On average, on a long road trip, I paid around $16 each time I used a Supercharger. Note that the company charges idle fees — you need to remove your car when the charging is done.
It's important to note, though, that if you have to rely on level-3 public charging, your situation is not ideal for driving an EV — get your home charging situation sorted out first.
EV charging: The takeaway
There you go. If you have a wall socket and maybe a long extension cord, chances are your home is ready for an EV. There's no need to get fancy with electricity.
Here are a couple of recap bullet points:
- There's no need to charge an EV at a fast rate at all times and every single time. You've got all night.
- In most cases, any existing 120V socket (level-1 charging) is enough to switch to EV. Especially for daily commuting or local driving.
- Unless you drive more than 100 miles daily, level-2 home charging (a charging station or the combo of a 240V socket + a mobile charger) is more about convenience and flexibility than necessity.
- You can always take the car to a public Level-3 charging facility when needed, the way you get an ICE car's tank refilled. (But if public charging is your only option, EVs generally don't quite make sense — get your home charging sorted out first.)
Here's the bottom line: Getting an EV charged is much more readily available than filling an ICE car with gasoline. All you need is a wall socket (a long extension cord may come in handy) or a couple of solar panels.
An interesting fact: gas stations need electricity, too. And they all have a socket somewhere for you to plug in your EV if you know how to ask nicely. But when out of gas, or during a power outage, there's not much the station can do about your ICE vehicle's empty tank.