How to Maximize Your EV's Range and Efficiency – CNET
How to Maximize Your EV's Range and Efficiency - CNET
You’ve decided which electric car is best for you, you’ve picked out and installed a home EV charger, and now it’s time to get out and drive.
With only a few exceptions, almost every EV available today boasts over 200 miles of range, and thanks to fast DC charging and more stations on the horizon, it’s easier than ever to travel long distances in electric cars. But even with range anxiety looming less large over the electric landscape, there are still benefits to maximizing your EV’s range. For example, stretching every mile per kilowatt-hour out of your battery will save money in the long term since electricity typically isn’t free.
With that in mind, we’ve rounded up a few tips and some of the best ways to maximize the efficiency and range of your electric car. And, as a nice bonus, most of these tips also apply to hybrid and plug-in hybrid cars as well.
Check your tire pressure regularly
Tires are extremely important to a car’s performance and efficiency, which is why many EVs arrive wearing special low rolling resistance rubber aimed at increasing range. However, underinflated tires create extra drag and friction as they roll along, reducing efficiency and increasing wear. You’ll want to periodically inspect your EV’s tires to ensure they’re properly inflated and free of damage for optimal range.
All tires lose pressure over time due to air naturally seeping through the rubber, slow leaks or punctures or even changing ambient temperatures — cooler air means lower pressure for the same volume of air, which is why I pay particular attention to my tires as temperatures drop in the winter months. However, too much air pressure can minimize the vehicle’s contact patch — literally, where the rubber meets the road — and adversely affect grip, increase braking distances and compromise safety. Look in your EV’s owner’s manual — or the handy guide often found printed in the door jamb — for the proper pressure to aim for using either a portable tire inflator or a public air station to top up as needed.
Many premium EVs feature tire pressure monitoring hardware that can alert you if the tire pressure drops too low, but their accuracy can vary and they tend to only notify when you’re already well below spec. I’d recommend regular manual checks with an accurate tire pressure gauge to ensure optimal performance.
Make smarter use of climate controls
Blasting air conditioning on a hot day can reduce an EV’s range by as much as 17% according to a 2019 study by AAA. And unlike a gas car, where heat is a free byproduct of combustion, warming an EV’s cabin with resistive heating elements can reduce winter range by as much as 41%, according to the same study. More recently, some automakers have attempted to soften the blow with more efficient heat pipe tech or energy saving “eco-climate” modes, but of your vehicle’s accessory systems, just turning off climate control has the most significant effect on an EV’s range.
Of course, if you don’t want to sweat or shiver through your commute, preconditioning your car’s cabin before you start your trip can help balance comfort and range. This could be as simple as parking in the shade, using a window sunshade or opening your windows for a few minutes to let the heat out before getting into your car on a hot day. Many EVs also feature software that allows drivers to schedule or remotely activate climate control while the car is parked and plugged in, conditioning the cabin using power from the plug rather than the battery. That way, the heating and cooling systems won’t have to work as hard when you hit the road, saving range.
If your car features heated and/or ventilated seats, making use of these features to heat or cool your body, rather than the air in the cabin, may allow even more efficient use of climate control.
Know when (and when not) to regen
Your EV’s regenerative braking system boosts efficiency by making use of your electric car’s powertrain to recapture kinetic energy when slowing down, rather than bleeding speed off as waste heat via friction brakes. So, obviously, one of the best ways to maximize range is to make as much use of regenerative braking as possible, right? Well, it depends.
Most EVs feature some way to adjust the amount of regenerative braking available — either via paddle shifters or a menu — and many even include so-called one-pedal driving modes that allow the car to come to a stop with maximum regeneration simply by lifting the accelerator. At urban speeds, where you’re stopping frequently for intersections, pedestrians or traffic, high regeneration levels can help dramatically boost range. Driving smoothly, predicting stops and beginning deceleration further out allows these higher regen modes to recapture more energy, boosting range. Conversely, abrupt and hard stops will use more friction braking, wasting energy.
But regenerative braking isn’t 100% efficient — not all of the energy can be recaptured — which is why on the highway, where speeds are higher and maintained over longer distances, it’s more beneficial to use no brakes at all. Using low regeneration, coasting when possible and maintaining a consistent speed will help stretch as many highway miles as possible out of each kilowatt-hour used. (This is likely why many German EVs, tuned for the high-speed Autobahn and American interstates, tend to favor coasting over regeneration on lift.)
Newer or more premium EVs — such as the BMW i4 and iX — often feature auto-regen modes that constantly adjust the regen level based on battery state, speed, distance to the vehicle ahead and, sometimes, even navigation data. This set-and-forget mode can yield range improvements, but may come at the cost of less consistent feeling deceleration.
Slow down, smooth out
Of course, the biggest factors affecting EV range are acceleration and speed.
Around town, rapid starts and hard launches tend to use more energy than gentler acceleration, partially because harder than necessary acceleration on public roads is usually followed by harder than necessary braking due to traffic, which, as mentioned earlier, wastes energy to heat. Blasting up to 50 mph only to immediately have to stop at the next intersection is a 1-2 punch of inefficiency. Smooth acceleration — “treat the gas pedal like an egg,” as I’ve often heard it said — will save energy and increase range. Many EVs have an Eco (or Economy) drive mode that will help smooth out acceleration by tweaking the accelerator pedal’s responsiveness (while also adjusting other vehicle systems to further reduce energy use).
Meanwhile, on the highway, the very air itself is the enemy of range. Modern EVs are amazingly aerodynamic, but at high speed air resistance and drag increase exponentially with respect to speed. Put simply, doubling your speed quadruples the amount of resistance your EV has to overcome, and every mile per hour you add to the speedometer requires more energy than the last to maintain that speed. So, shaving even 5 to 10 mph from your cruising speed can have a noticeable effect on how many miles you get out of each kilowatt-hour.
Other ways to boost range
If you’ve outfitted your EV with a roof rack that’s infrequently used, consider uninstalling it until needed. External accessories — bike rack, baskets, cargo boxes and even the rails themselves — increase the aerodynamic profile of the vehicle and can also increase drag and reduce range, especially at higher speeds.
Likewise, a heavier EV requires more energy to accelerate, so a trunk full of cargo may reduce efficiency a bit. We’re talking about especially bulky or particularly heavy cargo here. Small items — like your charging cable, a roadside emergency kit or a weekend bag — stuff shouldn’t matter.