Scenes of vehicles immobilized by flash floods have been commonplace this soggy summer in southeast Michigan.
As electric vehicles become common — including SUVs people buy expecting greater capability than a low-slung car — questions about how they deal with water become inevitable. Do they keep running? Are the occupants in danger of electrocution? Do the batteries short out and charge the water around them?
I had two recent experiences with electrified vehicles and water that shed some light on the topic.
First some basic safety principles:
—Never drive into water if you don’t know its depth. This includes highways and limited access roads that are below the surrounding ground or have retaining walls.
—Never drive or walk into fast-moving floodwater. It may still be rising, and even a shallow flow can sweep you off your feet or carry your vehicle downstream.
—If your vehicle stalls, abandon it immediately and seek higher ground.
—Water can hide rocks, curbs, debris and other obstacles that will damage or disable your vehicle.
Hyundai Kona EV stays high and dry
One drive was born of necessity. The other was planned, done under controlled conditions.
Driving home after a tasty crispy chicken don rice bowl dinner at Ima in Midtown Detroit in an electric Hyundai Kona compact SUV, I ran into an unforeseen storm that dumped 3 inches of water on some neighborhoods in less than an hour.
The electric Kona only comes with front-wheel drive. It’s no off-roader, but its 6.7 inches of ground clearance is more than most sedans offer, though not nearly as high as the water that overflowed medians and sidewalks around Woodward Avenue in northern Detroit and Ferndale.
The Kona’s wipers struggled with the downpour. I could see water more than grille-high on nearby vehicles, some of which had apparently stalled.
I slowed to avoid creating a wake, crossed my fingers and kept moving, sticking to the crown of the road, hunting high ground and watching for upwelling water that might warn of a blown manhole cover or storm grate.
I later measured some landmarks I noted during the storm. The water was nearly 2 feet deep in places. I avoided the worst, but when I got home, I saw what appeared to be a high water mark on the SUV’s doors.
The 201-hp Kona’s high-voltage 64kWh lithium-ion batteries are mounted in its floor pan. They undoubtedly got heavily splashed, possibly submerged, but the EV showed no ill effects and ran like a top the next day.
Hyundai makes no promises about the Kona EV’s performance in conditions like that, and wouldn’t make anyone available to talk about its engineering. But the little SUV came through the impromptu soaking fine.
Hyundai has recalled 82,000 Kona EVs around the world for battery fires.
Wrangler 4xe PHEV tested to the limit
Jeep, on the other hand, can’t talk enough about what engineers did to help the new Wrangler 4xe plug-in hybrid stay operational in up to 30 inches of water.
“We’re taught water and electricity don’t mix,” Wrangler 4xe chief engineer Mike Wiacek told me with a laugh. “Mother nature isn’t going to change just because we’re using a new technology in cars, but water fording equal to a (gasoline-powered) Wrangler was a necessity when we developed the 4xe.”
The 4xe, which recently went on sale, can indeed go through up to 30 inches of water, as I learned when I tested one in a snake-infested Texas slough earlier this year.
“There’s lots of high-voltage components within the frame” well below the 30-inch benchmark, Wiacek said. “We had to make sure they could survive, water, rocks, snow and being caked with mud."
Simply withstanding a dunking in standing water wasn’t enough.
“What if the owner needs to use high-pressure water to wash mud off high-voltage connectors and battery modules? We waterproofed it all for high-pressure water,” Wiacek said.
Among other tests, engineers put the 4xe through 16 hours of wetting with the roof off.
If the system still somehow ingests water and short circuits, software cuts voltage to the affected area.
“We need to protect occupants and first responders,” Wiacek said. “If we sense an area is compromised, we seal it off from high voltage. We shut the system down in a choreographed way.” The shutdown takes milliseconds from the moment a short is detected.
In addition, there’s no direct link between the high-voltage battery and the Wrangler’s chassis, giving the electricity no route to occupants.
Stellantis engineers applied the same controls to the Chrysler Pacifica minivan plug-in hybrid, he said.
