Most home EV charging happens overnight, and for good reason. Your car is parked for many hours, household demand is usually low, and the electrical grid often has spare capacity. Many utilities have built time-of-use plans around this pattern, so charging at the right time of day can lower what you pay for each kilowatt-hour. The details vary from one utility to another, so check your own plan before you change your habits.
What time-of-use pricing means
A time-of-use rate charges different prices for electricity depending on the hour. Prices are usually higher in the late afternoon and early evening, when many homes are cooking, running air conditioning, and returning from work. They are often lower overnight and sometimes at midday. Some plans also have a short peak window with a high price and a long off-peak window with a low price. Your utility's bill or website will show the schedule, the peak and off-peak hours, and whether the schedule changes by season or on weekends.
Check your plan before you set a schedule
Before you schedule charging, find out four things:
- Which hours are off-peak on your plan, and whether they apply every day.
- Whether the plan includes a separate EV rate, which usually requires a second meter on the charger's circuit, or whether the charger runs on the standard rate for the whole house.
- Whether weekends and holidays follow the same schedule.
- Whether the plan has fixed charges or other terms that might not suit your usage.
If you are not sure, call the customer service line for your utility and ask. Representatives can usually explain the rate in plain terms and tell you whether a separate meter is needed.
Setting a charging schedule
Many newer EVs have a built-in scheduling feature in the car's menu or in the manufacturer's app. You can usually set a start time or a departure time, and the car will begin charging so that it finishes when you need it. Some chargers also offer timers. Whichever method you use, make sure the charging window falls inside your off-peak hours and that the car will have enough range for the next morning.
A simple example shows the arithmetic. Suppose your off-peak window runs from 11 p.m. to 7 a.m., which is eight hours. A 60 kWh battery that is half empty needs about 30 kWh. At a charger rate of 9.6 kW, that takes roughly three to four hours before losses, so a start time around 11 p.m. or midnight leaves a comfortable margin.
Other things that affect your bill
Off-peak timing matters most when you drive a lot. If you drive only a few miles a day, you may use relatively little electricity, and the savings may be small. Also remember that the cheapest hour is not always the best hour for the battery. A battery that stays at a high state of charge for long periods can age faster, so avoid leaving the car full and parked for days unless you need that range. Your charging habits and your battery's condition work together.
How this applies to EVIQO chargers
EVIQO chargers are 240V units with a 25 ft cable. The 40A (9.6 kW) option adds about 38 miles of range per hour of charging, and the 48A (11.5 kW) option adds about 46 miles per hour. An overnight window is usually several hours long, so either option can replenish a typical day of driving within it. Check your utility's off-peak hours, then set the car's schedule so that the charging session falls inside them. All EVIQO chargers come with a 3-year warranty, and a 4-year extended warranty is available for an additional charge.