Home Charging for Electric Cars: Power Needs and Cost Savings
Over one million electric cars (EVs) are recharged at home every day, including mine! Contrary to popular belief, the amount of power needed for home EV charging is often surprisingly low. Some reports indicate that monthly electric bills can increase by only a few dollars while significant savings can be made on gasoline bills. But how much power does an electric car really need, and can you charge it at home?
Power Requirements for EV Charging
Electric car batteries usually have a capacity ranging from 30 to 100 kWh. To fully charge, a battery must receive an amount of electricity equal to its capacity. A 60 kWh battery, for example, will require 60 kWh of electricity to be fully charged. Power requirements vary depending on the battery size and the type of charger used. Two common home charging options are Level 1 and Level 2 chargers.
Level 1 Charging
Level 1 charging uses a typical 120-volt household outlet and is the slowest option, providing 3 to 5 miles of range per hour. Larger batteries may require 20 to 40 hours or longer to fully charge under this method. While convenient, it is not the most time-efficient option.
Level 2 Charging
Level 2 charging employs a 240-volt outlet similar to those found on electric dryers. Most EVs can be fully charged overnight using a Level 2 charger—typically taking about 8 to 12 hours. This type of charging is much more rapid, providing 15 to 30 miles of range per hour. Installing a Level 2 charging station in your home can be a worthwhile investment for convenience and efficiency.
Why Home Charging is Economical
Electric cars can be charged at home, either using a Level 1 or Level 2 charger. The cost of home charging can be significantly lower than using public charging stations. Here’s why:
Example of Home Charging Costs
Consider a Tesla driving 40 miles a day. This would require 10 kWh of power to recharge the battery daily. Comparing this to a 18 MPG car, a 5.3-gallon fill-up would be equivalent to a 20-mile drive. If you have a central AC unit, it can consume 3 to 5 kW per hour. For 5 hours of operation daily, you would need 15 to 25 kW of power, similar to the energy consumption of a 4 kW heat pump running 4 hours each day, totaling 20 kW of power. While some suggest running the AC less to save power, this is not typically necessary except on very hot summer days when it is advised to delay EV charging until about midnight or reduce AC usage during peak hours.
Many users benefit from special rates at night, such as 0.08 per kWh from 9 PM to 7 AM weekdays and all weekend, which can be significantly cheaper than the daytime rates, typically around 0.16 per kWh from 7 AM to 5 PM. Peak rates, such as between 5 PM and 9 PM, can reach 0.35 per kWh, prompting users to avoid certain appliances during these times. If you charge your EV at night with the lower rate, even with an area rate of 0.20 per kWh, you can achieve a full recharge of 10 kWh for just $2. If charged at night, the cost can drop to a mere $0.80, which is significantly more cost-effective.
Making the Most of Your Home EV Charging
Why would you want to reduce your charge? It’s like saying you only want half a tank of gas. Reducing your charge can sometimes serve a purpose, such as avoiding higher peak rates or conserving power during specific times. However, for most users, fully charging their EV at home, especially overnight, is the best and most convenient option. It can help save money on both utilities and fuel while minimizing the need to visit public charging stations.
Conclusion
Overall, home EV charging can be a cost-effective and convenient solution for many drivers. With the right charger and a good understanding of the power requirements and timing, EVs can be fully charged without significantly impacting your energy expenditures.