How Much Electricity Does it Take to Charge a Tesla?
Are you a Tesla owner? Are you looking to benefit from the cost and environmental savings of driving an electric vehicle (EV)? After all, one of the best reasons to purchase an EV is the long-term cost savings. In fact, on average, electric vehicle owners can save around $632 per year by charging their electric vehicle compared to paying at the pump. Of course, there are a lot of compounding factors here that play into annual savings such as your energy plan, the cost of gasoline, and your electric vehicle model. But all in all, moving from a gas-powered vehicle to an electric vehicle promises some sizable savings.
Now, what does this have to do with the amount of electricity consumed to charge a Tesla? For electric vehicle owners looking to maximize their cost savings, their first question is often, “How much electricity does it actually take to charge a Tesla?” A more specific version of this question is “How many kWh are needed to charge a tesla?”
If a Tesla owner were able to maximize their consumption of electricity and minimize the time it takes to charge their Tesla, they would be effectively optimizing their charging costs.
There are several factors that influence the cost of EV charging:
- Electricity Required to Charge a Tesla
- State of Charge & Depth of Discharge
- Understanding Electricity Consumption
- Tesla Battery Capacity
- Other Factors that Impact Charging
- Electricity Rates for Home Charging
- Impact of Weather on Charging
Our goal is to review these charging factors and evaluate the best ways to minimize their impact on cost.
Primary Factors Influencing EV Charging
From the amount of charge required to achieve your daily driving requirements to charging efficiency, there are many factors that influence the amount of electricity that a Tesla consumes. As we move forward in this section we’ll investigate each one of these factors.
State of Charge and Depth of Discharge
The State of Charge and the Depth of Discharge act as two of the most influential factors when it comes to electricity consumed by a Tesla. The State of Charge or SoC describes the upper limit of battery charge. For example, some Tesla owners may charge their Tesla’s to 95% overnight because they know they’ll deplete their charge the next day on a long commute, whereas, other Tesla owners may only need to charge to 70% since they have a shorter daily drive with their Tesla. In these examples, the State of Charge is 90% and 70% respectively.
And just how the State of Charge defines the upper limit of battery charge, the Depth of Discharge or DoC, indicates the percentage of the battery that has been discharged relative to the overall capacity of the battery. For example, some Tesla owners may deplete their Tesla battery to 50% whereas, other Tesla owners may delete their Tesla battery to 30% depending on driving requirements.
Understanding Electricity Consumption
As different Tesla owners set different State of Charge limits and deplete their Tesla to differing Depth of Charge limits, they are going to consume different amounts of electricity to meet their driving habits. Before we continue, we’ll do a quick review of electricity to better understand concepts such as current, voltage and power.
Current, which is measured in amperes (or amps), is the flow of electricity (or electrons ) passing from the source to the target. The higher the current, the higher the flow of electricity moving from source to target. Voltage can be thought of as the pressure of the electricity (or electrons) passing through the conductive material from the source to the target. The higher the voltage the higher the pressure on electrons moving from the source to target, resulting in faster charging times.
Power is a measure of how much work can be performed in a given amount of time. Power is equal to electrical current (ampere or amp) multiplied by electric potential (volts). When you take a look at your electricity bill, you’re likely to find that your electricity consumed for the month is defined in Kilowatt (1000 watts) hours (kWh), a measurement of power. This metric denotes the amount of power measured in kilowatts that are consumed per hour. Our guess is this value should be somewhere around 13 cents per kilowatt-hour as the national average here in the US is 13.19 cents per kilowatt-hour.
Tesla Battery Capacity
Another important metric to take note of is the battery capacity of your Tesla. Just like energy produced from your electricity company, Tesla battery capacity is measured in kilowatt-hours. This measure of energy denotes how much energy is used by the Tesla if it were to run for one hour.
How Many kWh are Needed to Charge a Tesla?
Electricity generated by your local energy provider is measured in kWh. For this reason, Tesla batteries are also measured using the same units. Determining how much electricity is required to charge a Tesla can be pretty straightforward once you know how to do it.
Next time you’re wondering, ‘How many kWh are needed to charge a Tesla?’, just remember energy over distance. What we’re really looking to express is how much energy is used by the Tesla for a particular number of miles traveled. If you find that you drive about 30 miles per day, under fair weather conditions, and you don’t run your engine at high RPMs, you’ll find that you get around 3 to 4 miles per kWh. Meaning, you’ll need to charge around 10 kWh following the 30-mile drive to get the Tesla battery back to its initial location.
Other Factors that Impact Charging
So far, we’ve put together a pretty simple model to assess how much electricity is required to charge a Tesla by taking into account a target State of Charge (SoC) and Depth of Discharge (DoD), how electricity is measured by one’s electricity company, and how electrical energy is measured in a Tesla battery. To build a more complete model let’s take a look at different cost models provided by an electricity company and a few other factors that influence electricity consumed by a Tesla.
Electricity Rates for Home Charging
f you look closely at the electricity bills coming from your energy provider, you may notice there are different ways electricity rates are applied. Depending on your location and your electricity distributor, there will be different ways to pay for your energy consumption. Four of the more common price offerings are: flat rate, tiered rate, time of use rate, and real-time rates. At the end of the day, all of these rates are still mapped to electricity measured in kWh. However, pricing can help inform how you use your electricity and charge your vehicle.
Flat Rate Pricing
With flat rate pricing you’ll have a pretty consistent electricity bill, assuming you’re drawing on average the same amount of electricity per month. Flat rate pricing is a great model for those looking for a consistent bill. These models eliminate the surprise of a higher than average cost per kWh at peak usage times. Unfortunately, you will also be losing out on the cost-saving benefits of charging at low usage times.
Tiered Rate Pricing
Tiered rate pricing breaks pricing into separate tiers based on consumption. For example, tier one may assign a specific cost per kWh for any consumption up to 50 kWh whereas tier two may capture 50 kWh to 100 kWh. Tier three will have yet a different charge for anything above 100 kWh. This model attempts to build in some cost savings based on usage. Again, the end-user loses the ability to save on their electricity costs by charging at certain times of the day when electricity is cheapest.
Time-of-Use rates attempt to encourage use of electricity during off-peak hours by lowering costs during off-peak times and increasing costs during high-peak hours.
Lastly, real-time rates base electricity pricing on dynamic demand throughout the day. While demand is high, the electricity company will charge a higher price for the electricity drawn and used, whereas, when demand is low, the electricity company will drop the price of electricity to encourage use. Real-time rates offer the best cost-savings opportunity for Tesla charging, assuming that one can dynamically charge during times where the electricity company drops the price per kWh.
Keeping track of all of this is easier said than done. Fortunately, there are third-party applications that can help you minimize your electricity bill and maximize your battery life.
Optiwatt is a free app that will automatically load your electricity rates and schedule your car to charge during the cheapest hours. It also takes into account annual adjustments in utility rates and will automatically update the charging schedule for winters, summers, and weekends.
How much does your electric bill increase with a Tesla?
The U.S. national average electricity rate is 13.27 cents per kWh, equating to $0.04 per mile driven.
Impact of Weather on Charging
For those Tesla owners that live in areas that reach near freezing temperatures or approach near 100 degrees Fahrenheit temperatures, Teslas actually require more electricity to achieve the same level of charge, compared to Tesla's charging in fair weather conditions. In both scenarios extreme heat or extreme cold, the Tesla is going to divert electricity to either warm or cool the battery. In doing so, Tesla drivers can expect to lose some efficiency in electricity and actually use more electricity to achieve the same charge level in regular months. To be fair here, we’ve really just scraped the surface when it comes to driving and charging a Tesla in extreme weather conditions. If you’d like to do a deeper dive, check out our write-up Tesla Extreme Weather Considerations - How To Optimize Your Tesla Driving For Winter Months.
Is it Expensive to Charge a Tesla?
The overall cost of charging a Tesla is not too high. Tesla Model X costs $15.29 to fully charge, while the Tesla Model 3 costs $7.65 to fully charge. This comes out to roughly 3 to 4 cents per mile.
Do you feel like a Tesla charging pro by this point? We hope so! If you’re looking to learn more about Tesla charging, check out our comprehensive guide The Comprehensive Guide to Maximizing your Tesla’s Battery Efficiency and Battery Life.