Tesla Charging and Battery Guide

If you’re looking into the possibility of getting a Tesla as your next vehicle, one of your first questions is most likely about charging. Who wouldn’t wonder about such an essential part of owning a Tesla? First of all, great job doing your research. There is a lot to learn when you are buying your first electric vehicle. By getting a better idea of what to expect with your new EV, you will have a much better ownership experience. Electric cars are fun to drive and help reduce our impact on the environment (and our wallets!).

This guide will help to walk you through every aspect of Tesla charging and batteries. We will cover equipment, charge speeds, battery types, increasing efficiency, best practices, and more. So stay with us as we take a look at everything there is to know about Tesla batteries and charging.

A Tesla charging from a wall connector
A Tesla charging from a wall connector

Before we get into the different options for charging, we should answer a common question about Tesla charging – Why do they have a proprietary connector instead of a universal standard? When Tesla started to build out their supercharger network there wasn’t a standard option available yet. EVs had not been developed enough for networks or standards to exist. They really paved the way for all current EV development. With a full charging network and many cars built, it would be difficult to switch to a different standard, at least here in the US.

In other countries superchargers were introduced later on and there were already many third-party charge stations, so it was easier for Tesla to provide a universal standard. So in some countries the Model 3 and Model Y come with a CCS standard charge port. For the Model S and Model X a CCS adapter is included. It is rumored that a CCS adapter will be made available for purchase in the US at some point in the near future.

When discussing charging you may notice that “connector” is used in place of the word charger for both home charging options offered by Tesla. This is because the wall connector and mobile connector are not chargers. They are simply supplying the charger onboard the vehicle. The vehicle’s onboard charger takes the AC power supplied by the connector and converts it to DC energy for storage in your car’s battery pack. For supercharging the onboard charger is not used. The supercharger provides direct DC power to the battery pack.

Home Charging Equipment

Mobile Connector – All new Teslas come standard with a mobile connector bundle. This bundle includes a mobile connector with a 20 foot long cord and a J-1772 adapter. The mobile connector is capable of charging your vehicle on a variety of outlets at rates of up to 32 amps. Without any additional adapters, the mobile connector is capable of charging your Tesla vehicle from a standard household 120-volt, 15 amp outlet (NEMA 5-15). The maximum charge rate on a 5-15 outlet is 12 amps / 1.3kW. This will give you around 2-4 miles of charge per hour. Some homes also have 5-20 (120v) outlets available, often placed outdoors or in garages. These will allow for slightly faster charging than a 5-15 outlet. You can identify a 5-20 by the t-shaped slot on one side.

Tesla Mobile Connector Bundle (mobile connector, 5-15 adapter, and J1772 adapter)
Tesla Mobile Connector Bundle (mobile connector, 5-15 adapter, and J1772 adapter)

Charging on a 120v outlet in cold weather will usually be even slower. In extreme cold a 120v may be just enough to maintain the current level of charge rather than adding range. So anyone in a very cold climate may want to consider a 240v charging option. Charging on a 120v outlet is not only slower than 240v charging, but also less efficient. If a 120v outlet is your only option and you typically don’t drive very far, it should work fine. If you have the option of 240v charging, it will give you better efficiency and faster charging rates. 5-15 and 5-20 outlets are the only two 120v options. All of the other adapters are for 240v outlets.

5-20 GFCI Outlet (20 amp / 120v)
5-20 GFCI Outlet (20 amp / 120v)

Mobile Connector Adapters

There are several adapters available from Tesla for the mobile connector. These adapters allow for faster charging speeds. The charge speeds depend on the type of outlet used. Available adapters include 5-20, 6-15, 6-20, 10-30, 14-30, 6-50, and 14-50. The most commonly used adapters are the 14-50, 14-30, and 5-20.

14-50 – The 14-50 is useful because some people choose to have a 14-50 outlet installed at their home for EV charging to allow for universal EV charging. This type out outlet can also be found at many RV parks which is very useful for road trips in remote areas.

14-30 – The 14-30 outlet is commonly found in homes with electric dryers. Some people choose to charge using this 240v outlet when their home already has the outlet in place. It’s not a good idea to unplug and replug each time you charge using a 240v outlet, so most people who regular charge on a 14-30 which is also used for a dryer will buy a splitter switch. The splitter will allow the power to be safely switched back and forth between the dryer and EV.

5-20 – The 5-20 outlet is very common in homes and outside of hotels and other businesses. The 5-20 outlet charges faster than a standard 5-15 outlet, so it’s a good option when 240v charging is not an option.

Below is a chart showing the charge speed for each type of outlet using a mobile connector with the appropriate adapter. For all outlets except the 5-15 you will need to purchase an adapter to charge using the mobile connector.

Mobile Connector Charge Speed By Outlet Type

OutletModel SModel 3Model XModel Y
NEMA 5-153323
NEMA 5-204434
NEMA 6-15711510
NEMA 6-201115814
NEMA 10-3017221421
NEMA 14-3017221421
NEMA 6-5023302029
NEMA 14-5023302029

For 240v charging you have a few options. The adapters mentioned above (besides 5-15 and 5-20) allow for 240v charging with the mobile connector. This will get you up to a 32 amps maximum charging rate depending on the outlet used. For even faster speeds you can use the Tesla wall connector.

Wall Connector – Tesla offers a faster option for charging at home. Their wall connector will charge at up to 11.5kW at 48 amps (7.7kW at 32 amps for Model 3 RWD). This will get you up 44 miles of additional range per hour (30mph for Model 3 RWD). The wall connector is the fastest home charging option that Tesla offers. It is installed by directly wiring rather than using a plug. Most people choose to have an electrician professionally install their wall connector.

A Tesla wall connector on a garage wall
A Tesla wall connector on a garage wall

Wall Connector Charging Speeds by Circuit Breaker Amperage

Circuit breaker
(amps)Maximum output
(amps)Power (kW @ 240v)Model S
(mph)Model 3 Dual Motor
(mph)Model 3 RWD
(mph)Model X
(mph)Model Y
(mph)
604811.5 kW3444-3042
50409.6 kW2937-2536
45368.6 kW2634-2332
40327.7 kW2330302029
35286.7 kW2026261725
30245.7 kW1722221421
25204.8 kW1419191118
20163.8 kW111515814
15122.8 kW71111510

Third-Party Home Chargers

There are lots of different chargers and brands out there for EVs. These can be used with a Tesla when an adapter is used. Brand like Enel X, ChargePoint, Grizzl-E, Wallbox, and others make charging equipment which is similar to a wall connector. The benefit of choosing one of these over a wall connector is that they work on many different EVs without adapters. So if you plan to own vehicles from other EV brands, then one of these chargers may be right for you.

Superchargers

Tesla’s charging network uses 480v fast chargers with charging rates of up to 250kW at V3 superchargers. There are also other superchargers with maximum charge rates of 72kW (urban superchargers) or 150kW (V1 and V2 superchargers). The V3 superchargers will get you up to 75 miles in 5 minutes which is great when you need a little extra range on the go. For a 0-80% charge on a V3 charger, it will be about 30 minutes. Charging speed and amperage can not be adjusted manually at superchargers like you can with home charging. It is best to use the navigation system and trip planner on your trip to allow your vehicle to plan for supercharger stops. This will reduce range anxiety, but more importantly it will automatically precondition the battery whcih will help you to achieve optimal charge speeds.

Pricing for superchargers will vary based on location. Most locations will charge at rate based on kWh of power used. Due to local laws and regulations, some locations may charge a per-minute rate. Rates will be shown for each charger location on your touchscreen when you select the location pin. Payment is seamless as it will use the credit card you have on file with Tesla.

A Tesla Supercharger in Basking Ridge, NJ
A Tesla Supercharger in Basking Ridge, NJ
Image Source: Curlyrnd, CC BY-SA 4.0, via Wikimedia Commons

Third-Party Public Chargers

Public fast charger networks are growing fast. There are many companies with charging networks and a few different types of charging connectors. Some of the avalilable charging networks include ChargePoint, EVgo, Electrify America, Blink, and Volta. Charging connectors include J1772 (type 1/AC/slow), CCS (Type 2/DC), and CHAdeMO (Type 2/DC). Charging connectors vary by location/network.

Battery Types

Tesla uses two different battery chemistries in their vehicles: nickel-cobalt-aluminum (NCA) and lithium-iron-phosphate (LFP). Both are lithium batteries, but the LFP batteries offer less range. This is why they are used in the Model 3 RWD, but not the long range or performance versions. There is less difference than it may seem though as the LFP batteries can be charged to 100% capacity without increasing battery degredation. NCA batteries should not be charged to 100% when possible as it may speed up battery degredation. So when you factor that major difference in, the two batteries are actually quite capable for most people. The only time that the NCA batteries have a true range advantage is when they are used for longer trips. You won’t have to stop as often to charge with a longer range vehicle, but the difference won’t be a big deal for most people.

In addition to variations in the battery chemistry, Tesla also uses three different types of battery cells: 18650, 2170, and 4680. The 18650 is used in the Model S and Model X. The Model 3 and Y use the 2170 batteries, but the Y may be switching over to the new 4680 soon. The upcoming cybertruck is also expected to use the 4680’s.

Low Voltage Battery

In addition to the “main” battery known as the traction battery or high voltage (HV) battery, EVs also have 12v batteries (low volatge battery). The 12v battery is used to run various vehicle features such as the lights, radio, windows, media system, and other small components. It is recharged by the high voltage (HV) battery rather than an alternator like an ICE vehicle. You don’t need to worry about charging the 12v as the vehicle will take care of that automatically, but it’s important that you are aware that your vehicle uses one. Just like in an ICE vehicle, if the 12v dies your vehicle will shut down – even if your HV battery is charged. So if the battery is old (more than 3-5 years) or if you get a warning about your 12v/low voltage battery, make sure to have it replaced as soon as possible. It’s not worth the risk of being stranded to try and get a bit more life out of an old battery.

Newer Teslas have begun to include a “12v” lithium battery instead of the standard 12v lead-acid battery which was previously used (and which almost all cars still use.) The new lithium battery which is made by CATL (they also supply high voltage LFP batteries found in some Teslas) provides more power, reduces weight, saves space, and has a longer lifespan/lasts through more charge cycles. It provides a nominal voltage of 15.5v, so while many will refer to it as a 12v, it’s really better described as a 15.5v battery.

Tracking Charging Costs

The Tesla app allows you to track charging costs. It breaks down charging costs into three categories (home, superchargers, and other) so you can more accurately determine costs. It will show you how much power was used for charging and what it cost. It also compares the price of charging versus the average cost of gas. kWh prices are based on the pricing of your local power company and can be manually set as well.

Tesla app charging stats
Tesla app charging stats

Increasing Efficiency

240v charging is more efficient than 120v charging, so it is always best to use 240v charging when you can. Some other ways to increase efficiency and range include lower speeds and acceleration, reducing cargo weight, using regen braking instead of brakes when possible, and using less air conditioning or heat. In the winter it is much more efficient to use a seat heater rather than turning the heat higher.

Best Practices

Keeping your car plugged in all the time will not cause battery degredation. Tesla recommends keeping the vehicle plugged in when not in use. The charge limit is what you want to focus on. Anything below 90% is fine. Ideally a lithium battery wants to sit at around 50% charge, but this is not realistic or practical for most people and the benefit is very low. Most battery conscious owners will set their charge limit to 70-80%. This is what works best for most people. You will want to avoid charging to 100% when possible. It’s fine for getting started on long trips, but you don’t want to let it sit at 100% as this will negatively affect the battery over time.

Charge rates are an important factor in battery life, but you won’t have to consider this factor as much as you may think. The maximum charge rate at home is just 48 amps. This is nothing to the Tesla’s battery, so reducing the amperage below 48 won’t have any measurable benefit for your battery. We know this based on the size of the battery, the relative charge rate, and the fact that it can safely charge at much higher rates. Remember, superchargers are up to 250kW. Charging at 48 amps is only 11.5kW.

There is one reason besides the battery why you may potentially want to lower the amperage. Higher amperage means more heat and this translates to wear and tear on your charging equipment and home wiring. It’s not something to worry about, but it is something to be aware of. Most people don’t think of the longevity of the charging equipment or wiring because they rarely have to replace their home’s electrical components. When you are dealing with high powered devices like a wall connector the components may wear out more quickly. It’s a good idea to have the charging equipment inspected ever so often to make sure that everything is still in good shape. This will prevent possible safety or efficiency issues.

Charge limit and amperage adjustment in the Tesla app
Charge limit and amperage adjustment in the Tesla app

Safety and Disclaimer

The information and opinions provided here are meant to give you an idea of the charging options available for Teslas. This is not professional advice and is not approved by or associated with Tesla in any way. Anything related to electricity is potentially dangerous, especially when considering wiring and electrical work. Always consult with a professional licensed electrician with experience in electric vehicle charging before altering or installing electrical equipment.