A Consumer Reports survey revealed that over 50 percent of car shoppers consider fuel economy a significant, even critical, part of their shopping decision.
Charging Your EV at Home
For most drivers, charging at home is the most convenient. Almost 90 percent of EV owners charge their electric vehicles at home, according to a recent J.D. Power study. The average EV driver will note an extra $20 to $30 tacked onto their utility bill every month, but that average depends on several factors: where you drive, how much you drive, what you drive, and how you drive can all impact how much it will cost you to charge your electric vehicle at home. To get an idea of how much it will cost to charge an EV, and how that compares to a gasoline car, check out our calculator below: Here are some key factors to consider, some of which you already figured out above:
EVSE – The electric vehicle supply equipment, usually called a home L2 charging station, is more efficient than the L1 charge cable you got with your EV. Depending on charger capabilities, such as power rating and smart features, this can cost between $200 and $1,500. Depending on installation requirements, this can add over $1,000 to a home EVSE installation.Electricity – Your electric bill is charged by kilowatt-hours (kWh), and the average kWh costs 13¢ across the United States. Electricity costs vary, depending on location, time of day, and government or utility incentives.Fuel Economy – Electric vehicle fuel economy is listed in kWh/100 mi (kilowatt-hours per 100 miles), usually 20 to 30 kWh/100 mi. If the EV battery capacity is 50 kWh and uses 25 kWh/100 mi, your range should be roughly 200 miles.Daily Drive – How much you drive will also impact how much it costs to charge your EV. If you drive 100 miles per day, you’ll need to restore 100 miles during your overnight charge cycle.Transmission Losses – Charging efficiency varies, depending on ambient temperature, the condition of the battery, and charger type. For L2 chargers, you can expect 5% to 15% transmission losses, while high-voltage DC chargers are closer to 99% efficient.
Doing the Math Yourself
Some basic calculations might go something like this, given a 50-kWh battery using 25 kWh/100 mi, and a 100-mile average daily commute – about 25 kWh – charging at home overnight at the average 13¢/kWh:
Cost Per Mile – 13¢/kWh x 25 kWh/100 mi = 3.25¢/miCost Per Charge – 3.25¢/mi x 100 mi = $3.25 per day
If your average commute is 100 miles per day, your EV recharging costs might amount to $70.42 per month. (Remember, that’s a pure EV and not a hybrid, which still uses gasoline.) Add in, at worst, 15 percent transmission losses for another $80.98 per month. Compare that to a 40-mpg hybrid vehicle’s whose fuel costs, at $3/gal, would be double that at $162.50 per month, and it’s easy to see how a pure EV can be a true cost savings.
Ways to Reduce Costs
There are ways to reduce your costs even further. Some utilities or local governments may offer special pricing for charging EVs, or you might be able to take advantage of lower off-peak electricity pricing, usually midnight to 6 AM. Also, solar panels and battery backups allow you to generate your electricity, though there may be some upfront costs associated with them.
How Long Should It Take to Charge My EV?
Charge time can be a massive consideration for EV shoppers because you’ll need to know if you can charge overnight to restore what you used during the day or will need to charge at your destination before returning home. A few simple calculations will help you figure out how much it will cost to charge an EV on the road. To do that, you’ll need to know your charge rate: The lower number between your vehicle and the charging station’s capabilities. For example, if your EVSE can deliver 8 kW and your EV accepts up to 5 kW, 5 kW is your maximum charge rate. Similarly, if your EV accepts up to 8 kW, but your EVSE can only deliver 5 kW, your maximum charge rate will be 5 kW. Let’s assume your EV can take full advantage of the L2 8-kW EVSE in your garage and the charge time can be estimated by battery capacity or range using the information we already know about your EV. We’ll need to add in transmission losses for a more accurate estimate so we can assume 90 percent efficiency.
By Capacity – 20 kWh ÷ 90% 8 kW = 2.78 hrs or 2 hours and 47 minutesBy Range – 25 kWh/100 mi x 100 mi ÷ 90% 8 kW = 2.78 hrs or 2 hours and 47 minutes
It’s good information to know because, as you can see in the example, you’ll be able to restore your daily drive in just a few hours. If you have a smart charger, you could even schedule it to start charging at 3 AM to finish by 5:45 AM when your morning coffee is brewing.
Charging Electric Vehicles on the Go
Charging an EV on the road using a public charging station is a different matter. The equipment is different, and there are various ways of paying for station use. At work, school, or some retail locations, you may be able to recharge on an L2 charging station for free, a perk for employees, students, or shoppers. Free is lovely, but limited availability could force you to look elsewhere. You can access other public-access L2 and L3 charging stations with an app, pay with a credit card or use NFC. Stations might be available on a subscription basis, pay-as-you-go, or both—some charge by the minute, by the kilowatt-hour, or per session. Knowing how much capacity or range you need to charge and how long it should take can help you estimate how much it costs to charge an EV when you’re not at home. Here’s an example: On a shopping trip, you realize you need to restore half your battery to get back home. In the public parking lot, you find a 95 percent efficiency L2 charger capable of a 19.2 kW charge rate and determine, based on your specific EV, that this process will take about 1.37 hours or 82 minutes. The charging station charges 6¢/min.
Charge Cost – 82 min x 6¢/min = $4.92
Another example: Let’s say you’re on a road trip, and you come across a 99 percent efficiency L3 charger capable of up to 300 kW DC fast-charge rate, and you need to restore 50 percent of your EV’s 50 kWh capacity, about 100 miles range. In this case, your charge time will be just over 5 minutes. This L3 charging station charges $1/min. (Other stations might charge by kWh, such as 43¢/kWh, for example.)
Charge Cost – 5 min x $1/min = $5.00Charge Cost – 25 kWh x 43¢/kWh = $10.75
You can see how charging nearly an hour and a half on an L2 charger might cost about the same as charging 5 minutes on an L3 charger, and possibly less. Our comparison 40-mpg hybrid can only go 66 miles on the same $5.00 no matter where it’s charged. While charger availability, time or capacity charges, surge pricing, or subscription offers can affect the price you pay in the end, the point here is that the cost is fairly stable regardless of where you publicly charge. Apps and online calculators are great ways to locate and pay for recharging. In general, it can be significantly less expensive to recharge an EV than refuel a conventional vehicle, depending on where you charge and live. Charging at home on an L2 charger is the most economical option in most cases.
