Electric Car Charger Basics

Congratulations on your electric car purchase, or at least thinking about it. The first thing you need to learn about driving electric is that your car is nearly always going to be fully charged when you go to use it, because you will plug it in as soon as you get home. Unlike a car with an internal combustion engine (ICE), where the first thing you do is check how much fuel you have, with an electric car, you just go, because it is nearly always fully charged!

The second thing will learn is that you don’t need to fully charge the car. You just need to charge it enough to get to where you can charge it next. This is very different from an ICE vehicle where you nearly always fill it up. Because you can plug in almost anywhere (there are 800,000 charging stations in the US for instance) you don’t really ever worry about it after the first two weeks of driving electric.

Charging Standards

The great thing about standards is there are many to choose from. Electric car charging is no different. Most electric vehicle conductive charging is standardized under IEC 62196. However, while IEC 62196 defines the signaling standard, multiple competing connector standards exist. The following five standards for the physical interface are common:

  1. Type 1/J1772 - The Type 1 or J1772 is a primarily US standard that supplies only AC current at up to 240v/80a (19.2kW), per the standard. Practically speaking, you won't find a J1772 charger that can supply more than 64 amps, and the vast majority supply a max of 32 amps, with many supplying  30 or less. The reason is the cost to create a rectifier that can handle the heat produced by rectifying a current above 32 amps, and only Tesla actually has a rectifier that can handle this. J1772 is the standard used in most public charging systems in the U.S., and which is natively supported in most electric cards in the U.S. Public charging stations typically supply no more than 32 amps at 240 v. A J1772 -> Tesla adapter that allows you to use this type of charger in a Tesla costs about $95.

  2. Type 2/Mennekes - The IEC 62196 Type 2 connector, is also known as VDE-AR-E 2623-2-2 or just Mennekes, from the company that designed it. Since 2013 it is the official plug in Europe, as the European Union had the immense foresight to designate such a thing. It is used in European Teslas. In the US it is found in VW, BMW, and Mercedes vehicles. The Type 2 connector is designed for AC Level 2 charging only, but Tesla Superchargers in Europe supply 90 kW DC over this adapter. In Europe it is common to have public chargers that have a male Type 2 connector and no cable. Each customer is expected to have their own cable with a female Type 2 connector on one end and whatever the customer needs on the end that plugs into the car, either a male Type 1 or a male Type 2 connector. 

  3. CCS - The Combined Charging System (CCS), is a variant that adds two pins for DC fast charging underneath the Type 1 J1772 connector or the Type 2 Mennekes connector. As Type 2 is the plug type used in Europe, European sourced cars that support CCS will often have a Mennekes connector on top. The standard supports up to 200 amps, but the draft specification provides for up to 125 amps at 850 volts, for 106 kW. Many cars that use this are limited to 50 kW, however. This is a rather large plug but several manufacturers now include this in their cars, including VW and subsidiaries, Ford, GM, BMW, and Daimler. The BMW i3 and Chevrolet Bolt both support this standard.

  4. Tesla - This is a proprietary adapter that comes with all new Tesla's in the U.S. It is a very compact adapter that can supply both AC charging at up to 240v/80a (20 kW) and DC charging at up to 120 kW (currently, but rumors are it can go higher). While there are adapters that allow the other standards to plug into a Tesla, there are no official or approved adapters that allow a Tesla charger to be used in a non-Tesla car at this time

  5. CHAdeMO - A standard originating in Japan for DC fast charging at up to 62.5 kW. You will find many of these around the U.S. but cars that have them typically have two charge ports, like the Nissan Leaf. There is an adapter for CHAdeMO -> Tesla that costs $450 but you would only ever use it when you are traveling, and there are always superchargers that cost less and are faster, so it isn't really worth it.

In the US you will often see chargers denoted as “Level 1” or “Level 2”. That’s a standard that is typically used for J1772 and Mennekes to denote the power output of the charger. Level 1 means 120 and Level 2 means 208 or 240 v, with a max charge current of 32 amps on a 40 amp breaker. Public chargers in North America are typically 240v/32a, but the current is also often shared between two plugs so you often will only get 240v/16a at a public charger. Clipper Creek sells a 48 amp 240 v charger that goes on a 60 amp circuit, and even a 64 amp 240 v charger. However, most electric cars, other than Tesla, can’t support more than the 7.6 kW supplied by a 240v/32a charger. Even all Tesla’s can’t use the 64 amp charger. The post-refresh Model S and Model X 60/70/75 kWh cars have a 48 amp on-board AC charger, while post-refresh 90 and 100 Model S and X have a 72 amp charger. Older Model S cars may have either, depending on whether they were built with a dual charger or not. The long range Model 3 has a 40 amp charger, and all other Model 3s have a 32 amp charger. 

In Europe you will see chargers denoted as Mode 1-4 according to the IEC 62196 standard. Mode 1 is charging from a regular single-phase outlet but has no control circuitry in the cable, and obviously none in the outlet, to enhance safety while EV charging. For that reason, Mode 1 is rarely used today. Mode 2 is also slow charging from a regular outlet, typically at 230 v and 10 amps, i.e. 2.3 kW in Europe. However, unlike Mode 1 it has safety circuitry built into the cable, a so-called CCID (Charge Current Interrupting Device). Mode 3 is either slow or fast charging using specific electric vehicle pin-outs. Mode 4 designates DC fast charging using specific EV connectors, such as CHADeMO, CCS, and Tesla Superchargers. In Europe Tesla superchargers use a Type 2 connector. EVs in Europe typically come with a Mode 2 cable, as well as a Mode 3 cable that has a Type 2 connector on one end for plugging into a public charger, and either a Type 1 or 2 connector on the other end to plug into the car. 

Power Delivery and Consumption

Power Delivery is pretty straightforward math. Battery capacity is measured in kWh, which relates to how much power they can deliver for an hour. Power is measured in Watts, or Kilowatts (kW). You get the wattage of a circuit by multiplying its voltage by its supplied amperage. Keep in mind that a circuit is only designed to deliver 80% of its rated amperage, for safety margin purposes. In other words, a 60 amp circuit delivers 48 amps max, a 40 amp circuit delivers 32 amps (which is a standard Level 2 charger), and a 15 amp circuit delivers 12 amps. To find out how long it takes to charge a car, figure out how many kilowatts you need to add, and divide that by the voltage of the charging circuit, multiplied by its amperage, multiplied by 0.8. The result is in hours. You can use this to compute what you need for a trip. 

For example, I've found that my Tesla Model S 75D draws between 330 and 440 WH per mile, depending on how cold it is outside, what settings I use for energy savings, how many people are in the car, etc. Adding a ski rack to it adds 10% to the consumption for instance. If I want to go 90 miles, with a ski rack, in temperatures around freezing, it will probably draw 440 WH per mile, so I would need 440x90/1000=39.6 kWh. My home charger supplies 48 amps at 240 volts, so I would need to charge for 39,600/(48x240) ~= 3.5 hours to return home with the same charge level I started out with before I plugged the car in. You should strive to keep 10-15% of your battery as a reserve, unless of course you have a plug-in hybrid or a dino-burning range-extender.

Included Chargers

All electric cars come with a "Mobile Connector" of some form. Teslas come with mobile connector that has a Tesla connector on one end and an adapter that comes with a NEMA 14-50 connector, for use with a 50 amp 240v outlet, and a NEMA 5-15, which is the standard household 15 amp 120v connector on the other. They used to also come with one J1772 adapter so you can use one of those chargers with a Tesla, but that is now a $95 add-on.  You can buy additional adapters for other types of wall plugs as well. You can plug a Tesla into a standard wall outlet, but that will take many many hours to charge from. For instance, if your car has a 75 KW battery, and you have two thirds charge, and you want to bring it up to 90%, it will take 12 hours and 10 minutes (75*.9-75*2/3)/(120*15*.8) It's really only useful if you don't drive much. You can also buy many other adapters for some of these mobile connectors, like the Tesla one.

Which Charger Do I Need at Home?

Different cars tend to use different charging standards and the standards they use may differ in different markets. Tesla in the US obviously uses the Tesla standard but in Europe they come with Type 2 connectors. Volvo, BMW, Mercedes, and Volkswagen ship cars with Type 1 connectors to the US, but with Type 2 connectors in Europe. Many cars also come with a fast charge option. Sometimes this is a Type 1 or Type 2 connector coupled with two CCS pins, like on the BMW i3, but in other cars, like the Mitsubishi Outlander and the Nissan Leaf, it is a CHAdeMO plug in addition to the regular Type 1 or Type 2 plug. Either way, you would not use the fast charge connector at home. It is primarily useful if you take the car on a road-trip.

The first step to decide what to install is to determine which connector to use. If you are in Europe, a charging station with a Type 2 connector is probably preferable, as the only cars that now come with Type 1 connectors in Europe are those that are primarily made for the US market, and even those may soon start shipping with Type 2 connectors to Europe. If your current car has a Type 1 connector (such as a Mitsubishi Outlander or Ford Fusion) you can use an adapter to charge it with a Type 2 charging station. In the US, if you have a Tesla, the Tesla wall charger or mobile charger is convenient and highly functional. However, if you now, or at some point want to charge another car at this charger you probably should consider one with a Type 1 plug (J1772) as it will work in nearly every car in the US.

The next question is how fast your charger needs to be, as measured in how many kilowatts it can put out per hour (kWh). Obviously, it depends on how fast you need to recharge your car. 

So, what to get for use at home? If you use your car mostly for commuting, and you can charge overnight, you can probably survive with a standard outlet, 110v/15a in the US and 230v/10a in Europe. If you need to drive it to nearly empty, and then two hours later need to go on another 300 KM drive, then, well, then you hopefully have a Tesla, and you will be visiting your nearest Supercharger. The fastest home charger you can get is a Tesla Wall Charger at 100 amps, and even the Model S and X with the 90 and 100 kWh batteries only support charging at 72 amps, so you would need to leave them for four or five hours to get enough range for a 300 KM drive. The Model S/X 75D, as well as the Model 3 have a 48 amp charging system, which gives you between 30 and 44 miles, 45-70 KM, of range per hour of charge, depending on which car you have.

The cheapest fastest option is to have someone install a 14-50 outlet on a dedicated 50 amp circuit near where you will use the car. Then you would use the mobile connector that comes with the car. The main cost of this is the cable run because it requires 6 ga wire, which runs about $1.70 a foot, and the electrician's trip fee. You could get into this option for sub-$200.

You can also install a Tesla Wall Connector. It costs $500. It would need to be hard wired with at least 60 amp service (also 6 ga wire) or up to 100 amps, which requires 3 ga wire, which is quite spendy. The nice part with this is that it is made for Tesla, so it is easy to use and works really well. The downside is that it won't work with any other electric car.

The next option, which is what i did, is to install a third-party charger. I have a Clipper Creek HCS-60. Clipper Creek numbers their chargers based on the circuit current, but they supply only 80% of that, so mine supplies 48 amps at 240v. It is hardwired just like the Tesla charger. I use it with an adapter, because it, and all chargers from hereon out, use the J1772 connector.

You will find a lot of Blink and ChargePoint chargers out in public, and they both make home chargers as well. They have more features than the Clipper Creek one (including WiFi connectivity) and, frankly, look better. Most of the features are things you don't really need, like the ability to schedule charging for times when power is cheaper (it's not around here) and tracking of when the car is charged (Tesla and most other EVs include that already). They max out at 32 amps, which is why I went with Clipper Creek since it provides 50% more power. All of them need to be installed on a dedicated circuit with a properly sized breaker and wire. The charger must not provide power that is greater than 80% of the circuit it is on. 

Here’s a handy chart adapted from data on Tesla’s website. It gives the range per hour of charge assuming a consumption rate of 262 wh per mile for a Model 3, 340 wh for a Model S, and 384 wh for a Model X. There is a more comprehensive chart on the Clipper Creek website

Charger Capacity

Tesla charge speed: Miles of range per hour of charge


Circuit Breaker

Maximum Output

Power at 240 Volts

Model 3

Model S

Model X



19.2 kW




This is primarily useful if you are putting two chargers on the same circuit. No electric vehicles today support charging at 80 amps.



17.3 kW




This is the maximum supported by Tesla’s with a 90 and 100 kWh battery and those with dual charger onboard support. 



15.4 Kw




Tesla’s Wall charger and the Clipper Creek HCS-80 can  supply this



11.5 kW




This is the maximum charge current supported by the Model 3 and the 60/70/75 kWh Tesla Model S/X. The Clipper Creek HCS-60 supports this rate of charge



9.6 kW




This is your max charge rate with the Tesla Mobile Connector and a 14-50 outlet



7.7 kW




This is the max with most Level 2 home chargers. This is also the max rate supported with other cars, such as the Nissan Leaf with the upgraded 6.6 kW charger, although it draws only 208v, and the BMW i3.



7.2 kW




Many public Level 2 chargers support this rate



5.7 kW




Common in a Level 2 home charger



3.8 kW




This is a common current for a 240 v outlet in the U.S. It is the maximum supported by the T8 series, the older Nissan Leaf, and any other car with a 3.3 kW charger, although they draw only 208v.



2.8 kW




This is what you get on a normal household outlet in the US

Useful Resources

  • ChargeHub has a good primer that also goes through the North American charging networks

  • Plugshare is a great app for finding public charging stations

  • ClipperCreek has a good chart on how long it takes to charge various cars with their products. 

Feedback on this Document

If you have feedback on this document, contact me at jjdives@live.com. If you like this information, do all of us a favor and replace an ICE car with an electric one. If you buy a Tesla, you may use my referral code, jesper4678, to get some free supercharging. Until the end of 2020 Tesla is offering a year worth of free supercharging on a new Model 3 or Y.


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