From consumerreports.org
Customizing your electric-vehicle-charging habits can help save you plenty of time and money
By Nick Kurczewski
August 04, 2017
Now that the Chevrolet Bolt EV and Tesla Model 3 are on U.S. roads, car shoppers have a choice of more affordable electric vehicles that can go more than 200 miles without a recharge.
These cars will need to be charged, however, and given their longer-than-typical range, that can take some serious time. So when does it make financial sense for an owner to get a high-speed at-home charger installed? It’s not a cheap decision, as they can run from hundreds of dollars to more than $1,000. Key is to choose based on your real needs, not just the potential use outlined in marketing materials. Many electric-vehicle owners will likely find that they on a daily basis, they don’t deplete more of the battery than can be replenished overnight using a basic 120V connection.
Intelligently customizing your EV charging routine can save you cash in the long run and can help you avoid hours wasted waiting to get back on the road once your car battery runs down.
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There are several key considerations: Your car’s overall driving range, your personal driving habits, your daily routine, the availability of charging stations along your commute, and whether adding a high-speed charger at home would add real value to your home’s potential resale value.
A chart at the end of this report offers suggestions about which level charger consumers might consider, based on driving needs, including commute times.
There are three types of chargers, but only the first two are really meant for your home:
Level 1: This is a normal 120-volt connection, which uses any standard household outlet; there are no extra costs here. The downside is that charging times can be painfully slow.
Level 2: This uses a higher-output 240-volt power source, much like one that you’d plug your oven or AC unit into. Charging times are much faster than Level 1. Excluding installation costs, fitting a Level 2 outlet in your home garage typically runs from as low as $300, to approximately $1,200, depending on the make and model of the charger.
Level 3: These fast-charging devices use very high voltage and can add 90 miles of range to an EV in just 30 minutes in some cases. These chargers, however, are extremely expensive, costing tens of thousands of dollars, and routinely using a Level 3 charger can ultimately hurt your car’s battery, so we wouldn’t consider one for home installation. Besides, they are cost prohibitive for most consumers.
Gil Tal, a researcher of transportation and travel behavior at the University of California at Davis, says EV and plug-in hybrid owners should experience their EV vehicles first before making the decision about installing a charger at home.
“Buy it and drive it,” he says. “Drive your car and see what makes the most sense for you.”
Although that might sound obvious, Tal’s research involving 26,000 EV owners in California and his studies in 14 other states showed early adopter EV owners rushed in and installed Level 2 chargers, whether they truly needed them or not.
When it comes to owning an EV, Tal says simple charging solutions are found only at the extremes of daily driving routines. For example, Level 1 home charging simply won’t work for anyone who drives longer distances and has no time, or opportunity, to recharge their car during the day. Upgrading to a Level 2 charger for that owner becomes a necessity, especially if the car is fully electric and there aren’t any public charging stations at the workplace or nearby.
For that owner, adding a dedicated 240-volt power source in your garage could be a quick and easy installation, Tal said, and it could appeal to future EV-owning house hunters.
Do your homework and be aware of all your charging options, especially around your daily commute. That’s the advice of Gabe Shenhar, program manager of vehicle dynamics at Consumer Reports. “If you live in a community that has public charging, say at the train station, and your car is going to be parked there most of the day, you might as well take advantage of that, and that might eliminate the need to invest in a Level 2 connector in your garage.” Otherwise, he says, “For a true EV, Level 2 is just about essential” if it’s the only source for power.
Also, explore the energy options with your local utility. Lower, off-peak rates are common, though they may vary depending on whether you are using a Level 1 or Level 2 charger.
Shenhar stresses the importance of knowing exactly how fast your electric or plug-in hybrid can accept a charge, using either a Level 1 or a Level 2 charger. He points out that it took CR 10 hours to recharge the electric-powered Chevrolet Bolt using a 240-volt power source. If you use a standard 120-volt power source, he says, be ready to wait longer than 24 hours for your Bolt to fully recharge.
One advantage of these new higher-range cars is that they should seldom use all their charge in a single day’s commute. With ranges that top 200 miles and average daily commutes of less than 50 miles, it should only be a matter of topping off the battery at night and not starting from zero.
An important consideration may be your vehicle’s “acceptance rate,” an often overlooked technical aspect that has a major effect on an EV’s charge time. Generally speaking, higher acceptance rates (6.6 kWh vs. 3.3 kWh) mean less time will be spent plugged into an outlet because the vehicle is able to more quickly convert incoming power to onboard battery storage.
On the other hand, a typical plug-in hybrid might have more limited electric range but also takes less time to recharge. “If you buy a plug-in hybrid, there is almost zero chance you won’t fill it up overnight with a Level 1 charger,” says Tal at UC Davis. A plug-in hybrid also has the fallback option of operating using its gas-powered engine once its electric power has been depleted.
As for going all in on a DC fast-charging system (or Level 3), forget it. Their prohibitive cost and high power levels make them unsuitable for home installation, Tal said. It would be the equivalent of building your own gasoline station to keep your car or truck fueled up.