As you likely have heard, Hurricane Helene has been wreaking absolute havoc across the American Southeast, wiping entire towns off the map and causing all sorts of severe flood damage. As if all of the destruction isn’t enough, folks have been worried about EVs catching fire after being flooded with water — saltwater especially. There was at least one incident in Florida where a Tesla Model X burst into flames apparently due to saltwater incursion into the battery, and there could be more to come.
We actually wrote about the danger of flooded EV batteries a while back, and got an actual battery engineer to explain what is happening and why, and we’ll recap that for you here.
Here’s the video of the flooded Pinellas County garage where the Model X was; because of the coastal location, the floodwaters here were saltwater, and that was likely a factor in the fire:
CAUGHT ON CAMERA ▶️ Video shared by officials shows the moment saltwater flooding caused by Hurricane Helene led a Tesla to catch on fire and quickly go up in flames.
We VERIFY why it's such an issue with electric vehicles: https://t.co/NXI9FOUn2i pic.twitter.com/CXaMu9BK5Z— 10 Tampa Bay (@10TampaBay) September 28, 2024
There were other EV battery/saltwater flooding-related fires as well:
So, why is saltwater in particular a factor? Our battery engineer explained it like this in our piece “An EV Battery Engineer From A Major Carmaker Explains Why Flooded EVs Catch On Fire”:
… the problem begins with salt bridges short-circuiting bus-bars and other high-current components in the pack – essentially exceeding the creepage and clearance distances because not only is the salt water itself more conductive than air or air-filled potting, but the salt residue left behind can be much more conductive, forming a path for current to flow.
BEV propulsion batteries … have ~300V or more (Hyundai’s newest EVs are at 800V), which is a lot more electrical “pressure” (to use a hydraulic analogy) to drive current through an electrical short, resulting in much more current (flow) and thus more heat generation. This heat will be generated in the cells themselves, and in all the electrical bussing that is part of the circuit, as well as in the salt bridge.In the case of a “soft,” relatively high resistance short, this may take a while before the temperature gets critical, but since the battery has a lot of capacity and is pretty well sealed off with little heat transfer to the environment with the car off (as in no active cooling systems operating), the heat has nowhere to go, and things still heat up.A “hard”, low resistance short makes this much worse since most Li+ chemistries can output much more current than is safe for the cell (and the restrictions to prevent this are in the battery control module, motor controllers, inverters etc, all of which are off), heating the cell up.If the pack is filled with water, it is harder to build up enough heat since water is very good at absorbing heat, warming up and then turning to steam before venting from the pack, but eventually it boils off (possibly leaving behind more salt bridges). Either way, the cells get too hot through their own heating and being heated by the electrical bussing carrying the current…
EV Fire Safe, an organization supported by Australia’s Department of Defense and that “provides free electric vehicle fire safety knowledge for emergency responders,” discusses this on its website, writing:
Why does a submerged EV have a higher risk of battery fire?
It is perfectly safe to drive through heavy rain & puddles in an EV. Electric vehicle safety systems & battery packs are designed to be safe in water, even if fully submerged (however all emergency agencies do not recommend driving through flood water).
However, EVs that have been submerged in water, particularly salt water, for an extended period of time – typically hours to days – may have a higher potential risk of experiencing a battery short circuit, which may result in a battery fire.
While our research indicates ingress of water to an EV battery pack increases the risk of thermal runaway, there is no data to indicate likelihood.
Here’s part of what Tesla advises if an owner’s car gets submerged:
If a submersion event is in the forecast and it is safe for you to move your vehicle, we recommend you attempt to move your vehicle to a location that is not at risk or to higher ground.
[…]
Safely tow or move the vehicle at least 50 ft (15 m) from structures or other combustible materials such as other cars and personal property.
Flooding is, of course, disastrous to all cars, but combustion cars simply don’t have chemical energy stored in the same way that would allow for fires to start – and restart – when exposed to flooding, saltwater or otherwise.
There’s a hell of a lot of energy in an EV’s battery, and once the process of thermal runaway happens – that is, when salt bridges or other factors cause shorts that cause heat to be generated, leading to a cascading and uncontrollable self-heating state – it is extremely hard to stop.
If you’re in an area affected by this sort of flooding, this is something to be aware and wary of. I’m not saying avoid every EV you see, but if you see a Bolt or a Tesla or a Ioniq 6 or F-150 Lightning submerged nearby, maybe wade in the other direction.
Well, I guess we’ll be seeing fewer sketchy flood cars for sale in the future.
Solution: batteries in the roof.
Yes, more chance of a rollover. Gotta take the good with the bad.
Solution #2: Emergency lifts in garages.
“I swear honey, this sweet new two-post lift is just a safety factor for our EV if the garage ever floods.”
Having seen the after effects of a seawater flooded car, I’m not surprised at all. The salt is EVERYWHERE. Every harness gets wicked, salt stains on every surface, rust on any exposed metal.
This just doubles-down on the “flooded cars are a write-off” notion. We just now also need to be aware of how we store BEVs that have received this treatment.
ten feet or more around any Flood totaled Ev is the norm. Often scrap yards will not take them without he battery removed.
I suppose this way the EVs are ensuring that will be write-offs, rather than sketchy salvage titles.
Sucks for the firefighters tho.
I think Torch should write all vehicle fire related articles going forward, just as a running thing.
I agree with others, I’m thinking the car had to have driven through some high waters before being parked as that doesn’t seem like very high in the garage.
This is probably a bigger issue for air cooled batteries like in Leafs and Kia Souls and what not, it’s one reason I don’t bring my old Ranger through car washes as the pressurized under carriage blasting may get into the battery compartment and wreak havoc on the electricals, even with just normal fresh water.
Maybe a follow up article on which EVs have the most, and least, sealed battery compartments? I thought Tesla was sealing theirs in foam now to curb this kind of thing.
Torch’s Torches!
So, let’s all keep driving ICE, that will surely clear up the frequent mega hurricane issues.
Probably wouldn’t. but if we drove them all to space between the earth and the sun we might block a fraction of a percent of incoming sunlight.
I’m in favor of reducing emissions as much as we can but by the same token, even completely removing the ~10% of global CO2 emissions that personal cars account for isn’t going to stop these from happening.
Well good thing we are not only doing that then. I have lived long enough to see constant smog warnings and yellow skies clear way for blue in Southern California. Sure we still do spare the air days but there is visual evidence that what we are doing is working.
I got curious and went looking for numbers. Talk about a dramatic improvement over the decades: https://www.laalmanac.com/environment/ev01b.php
As much as CARB can be a giant pain in the ass, it’s hard to argue with the results.
This gives me a
greatidea for a B movie franchise:“It started in the early 21st Century. The annual hurricanes, made more powerful and frequent from climate change, washed EVs out to sea where they would sink and combust. Soon the octopus learned the value of fire and, with the long lifespans granted to them by the life-extending chemicals that had passed through the systems of old Floridians to end up in the seawater, it was a mere few decades before they were ready to make their first move against mankind. Now it is their time, time . . . for the Rise of the Kraken!”
Remove that strikeout from your great modifier. I would watch the shit out of that movie.
There’s also brackish water that flooded up during the storm. (Where sea water and fresh water mix) It’s not as salty as pure sea water, but salty enough.
Can we agree that pretty much every possible open body of water is conductive(and corrosive):
https://andyjconnelly.wordpress.com/wp-content/uploads/2017/07/electrical-conductivity-of-common-solutions3.png
I mean we have so much evidence of it:
https://www.reddit.com/r/CyberStuck/comments/1c4o5vm/another_bricked_truck_the_first_comment_on_this/
The Cybetruck POS can get bricked by a simple car wash
https://www.theregister.com/2024/04/20/cybertruck_car_wash_mode/
So the only times electronics are not affected by water is when they are not powered on, I can confirm I have cleaned electronic boards in water using ultrasonics and they survived. Also they have to be dried like quick, really fast and in a hurry.
On the other hand this below is the work of “fresh” water(even tho supposedly the car only sat in the water for like a few hours – the one that got underneath things, was there for much much longer):
https://drive.google.com/file/d/1S3voB6IwDlvVsBPSv3zvCg72o-f5EIT7/view
https://drive.google.com/file/d/17-lXukGcGcTjJOATWd2k4dsIjQIAmJaD/view
Unfortunately the copper is still one of the best conductors today, and sadly it can corrode just by being in open air, forget about water.
Sadly the electric cars are more or less advanced battery powered electronic shavers, so good luck making the whole thing water tight.
So far all of them claimed that they can do some water fording, The jaguar advertisement comes to mind, and there was some chinese video circulating, I highly doubt all of this, unless there is some serious waxing, and prep work like this one:
https://www.youtube.com/watch?v=kOgQOHaW8KY
My undertanding is that one such prep work takes like good up to 6 hours, and you can only be in the water for 1 hour ..
https://cj3a.info/sibling/cjv35u/evolution.html
David might enjoy the last link and probably attempt it 🙂
The danger of an ICE car submerged in water very low explosive/fire reaction with an EV higher danger. Plus power is out for weeks your EV provides power for a day then no car. I just think people who went through this will be less likely to buy EVs. And I think 100% EV is gone as every emergency vehicle operator will be thinking how would we keep an EV operating 24 hours a day for different crews rescuing everybody? You can’t take a few hours off while people are dieing and fires are burning.
Holy strawman argument Batman!
“EV provides power for a day then no car” –> More like several days for a full house, even more if it’s just the fridge.
Nobody serious was advocating for 100% EV, especially not emergency vehicles. At least, not with the current state of technology. Which, as you may not realize, is advancing quite rapidly.
Our remote control flying club is right next to an estuary.
Salt water can short out 6S (22.2V) LiPo packs. Ask us how we know.
Why aren’t the battery packs completely watertight? I thought they are liquid-cooled with a closed loop cooling system and the cells themselves are glued in a foam-like insulating material.
It’s possible to make them fully waterproof, although it would make the vehicle more costly, and likely more heavy and complex.
I don’t know if it’s a price worth paying to make a road car sea worthy.
Probably better to drive the car to higher ground as Tesla suggests, and not just let it sit there slowly filling with flood water.
What I’m hearing is that Brazil would be right to mandate amphibious cars. /s
That video is not scary AF at all. /s
Salt Life was a hot trend for while…
God I hate those Slut Life stickers. Praise the Lord they just went bankrupt.
It still is wherever they sell margaritas.
this is why I stick with a good old steel body ICE vehicle, because salt water doesn’t affect it at all.
BUT WHAT IF THE OTHER DIRECTION IS TOWARD A SHARK!!!!!
Lure the shark into the submerged Bolt, enjoy tasty fried shark later?
But the calories.
It’s the floating balls of fire ants and swimming water moccasins that are more common in this situation.
Alligators
Not so much. I’ve been through Hurricane Charlie, Ian, Tropical Storm Gabrielle, Debbie, and a few more. Never saw an Alligator during those times. (I’m sure they’re out there somewhere.) Usually, you see them during a regular day on the banks or in the ponds and canals.
The best place to see them is Myakka State Park. You can Kayak and canoe right past them.
DSC_7097a-768×516.jpg (768×516) (hikeitflorida.com)
Snapping turtles then.
Definitely!
Glad You and the Commodore made it through Helene, speaking of which, haven’t seen a “the worst cars” in a while.
Makes me wonder what’s going to happen to them in the states that use salt and chlorine slurry to melt ice and snow on the roads.
Who knows where that Tesla had been but the water level in the garage looked minimal.
I thought the same thing, looks barely an inch up the sidewalls. Which probably means the owner thought they’d made it through whatever water they hit okay, and then…yikes.
Probably driven through roads flooded up to the top of the bumper most likely. Happens a lot after the storm.
That video having sound was SO satisfying.
yes. i was surprised at how noisy the fire was as it started.
banging and growling
Similar to “tin whiskers”, silicon crystals that grow on circuit boards, bridging current in places it was never intended to. Next thing you know, your device is bricked.
Or Toyotas experience unintended acceleration.
Huh? PAY ATTENTION, BOY, PAY ATTENTION!
We’re talking about flooded EV’s catching fire here.