How do EVs handle flood damage long term?

Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

I suspect the possibility of electrical issues would plague flooded EVs similar to ICE vehicles, with the possibility of high voltage issues creeping in as well.

Blair said:
I suspect the possibility of electrical issues would plague flooded EVs similar to ICE vehicles, with the possibility of high voltage issues creeping in as well.

Ya. The issues with ice vehicles have nothing to do with the engine itself. It’s just general issues with wiring and moisture. The water gets into the frame and it’s hard to get out. Wiring for brake lights and windows and all the different sensors in modern cars will be susceptible to corrosion over time. This has nothing to do with the engine itself.

Stay away from the flooded ones for sure.

A great tip I saw in a different thread: carry a white cotton glove to any car for sale and reach under the driver or passenger seat and rub the metal support/mechanism. If you get rust on the glove, the car has probably been flooded.

Orin said:
Stay away from the flooded ones for sure.

A great tip I saw in a different thread: carry a white cotton glove to any car for sale and reach under the driver or passenger seat and rub the metal support/mechanism. If you get rust on the glove, the car has probably been flooded.

Oh, that is clutch!

Typically, what seals the deal, on a car being ruined due to flooding, is water getting into the computers. There’s no fixing that, and there’s no drying that out. It’s not that hard to take an interior out of the car and dry the car out. You can’t do that with the computer in the front of the center console though.

Salt water completely destroys everything though, not just cars, my examples above reference freshwater flooding.

Rafe said:
Typically, what seals the deal, on a car being ruined due to flooding, is water getting into the computers. There’s no fixing that, and there’s no drying that out. It’s not that hard to take an interior out of the car and dry the car out. You can’t do that with the computer in the front of the center console though.

Salt water completely destroys everything though, not just cars, my examples above reference freshwater flooding.

That water ain’t all that fresh.

If I had a car that was flooded, within 72 hours I would tear it down to components and blast everything with distilled water. (Which I’d have plenty of out of the dehumidifiers lol). Then pray. And I would expect some failures. That car would never be sold and taken to the scrapper.

Keagan said:

Rafe said:
Typically, what seals the deal, on a car being ruined due to flooding, is water getting into the computers. There’s no fixing that, and there’s no drying that out. It’s not that hard to take an interior out of the car and dry the car out. You can’t do that with the computer in the front of the center console though.

Salt water completely destroys everything though, not just cars, my examples above reference freshwater flooding.

That water ain’t all that fresh.

If I had a car that was flooded, within 72 hours I would tear it down to components and blast everything with distilled water. (Which I’d have plenty of out of the dehumidifiers lol). Then pray. And I would expect some failures. That car would never be sold and taken to the scrapper.

In my head the whole time I’m thinking, if the water gets higher than the bottom of the door, and fills the car, the car is pretty much destroyed.

If there’s just a few inches of water on the floorboard, that might be able to be remediated, if the water’s clean enough…

Rafe said:

Keagan said:
Rafe said:
Typically, what seals the deal, on a car being ruined due to flooding, is water getting into the computers. There’s no fixing that, and there’s no drying that out. It’s not that hard to take an interior out of the car and dry the car out. You can’t do that with the computer in the front of the center console though.

Salt water completely destroys everything though, not just cars, my examples above reference freshwater flooding.

That water ain’t all that fresh.

If I had a car that was flooded, within 72 hours I would tear it down to components and blast everything with distilled water. (Which I’d have plenty of out of the dehumidifiers lol). Then pray. And I would expect some failures. That car would never be sold and taken to the scrapper.

In my head the whole time I’m thinking, if the water gets higher than the bottom of the door, and fills the car, the car is pretty much destroyed.

If there’s just a few inches of water on the floorboard, that might be able to be remediated, if the water’s clean enough…

From what I remember, that will total a car here in Illinois by law.

Rafe said:

Keagan said:
Rafe said:
Typically, what seals the deal, on a car being ruined due to flooding, is water getting into the computers. There’s no fixing that, and there’s no drying that out. It’s not that hard to take an interior out of the car and dry the car out. You can’t do that with the computer in the front of the center console though.

Salt water completely destroys everything though, not just cars, my examples above reference freshwater flooding.

That water ain’t all that fresh.

If I had a car that was flooded, within 72 hours I would tear it down to components and blast everything with distilled water. (Which I’d have plenty of out of the dehumidifiers lol). Then pray. And I would expect some failures. That car would never be sold and taken to the scrapper.

In my head the whole time I’m thinking, if the water gets higher than the bottom of the door, and fills the car, the car is pretty much destroyed.

If there’s just a few inches of water on the floorboard, that might be able to be remediated, if the water’s clean enough…

Yeah all that interior would have to come out down to the floor pads, and then, keep it wet until it can be properly cleaned. Much of that would need to be simply replaced, can’t clean floor pads economically.

It’s a teardown and reassemble regardless.

What destroys flood cars is in two groups.

The interior is easy to describe, it gets wrecked with mold and nasty smells that pop up on humid days.

The mechanical killer is wiring. Every wiring connection in the car has gaskets to keep out splashing rain. Go pay $2 to go into a pick-n-pull sometime and just go around disconnecting connectors and look at how they’re made.

The problem is water has weight. Every 2 feet of water depth increase pressure by 1 PSI, or about 20 kPA per metre if you’re batting on that team. So 2.5 inches of covery is still 0.1 PSI, and that’s enough to push dank flood water right past those gaskets and into the interior of the connector where the contacts are.

However, the gaskets do a bang-up job of preventing the water from leaving! Thus they entrap the water and sit there corroding, corroding, corroding.

Now electronics are a different deal, either they get absolutely wrecked due to what corrosion does to a circuit board, or they are immune because they are “potted” (dipped in epoxy) But if the connector on their edge is corroded out, it’s just as bad.

Keep in mind, wiring harnesses are no joke. They are expensive kit - either to buy new or painstakingly remove from a wreck without damage. So the harnesses themselves are a “component” that can fail.

Add to it, the failures won’t be “dead car”, but rather “mysterious niggling malfunctions that take hours of expensive technician time to chase down”, and then an endless stream of problems like this. Because the troubleshooting trees are written assuming normal failure probabilities, not the most likely culprit is a connector.

If I had a flood car, I would deconstruct it, and painstakingly inspect every component. That’s a huge amount of work even for me, a DIYer, so the economics of it are pretty dubious.

Notice I haven’t said a solitary thing about ICE engine or transmission. Those might get off scot-free, with repeated vigorous oil changes. Worst case they need a conventional teardown/reassembly to polish up metal parts, replace gaskets etc.

The big battery, you’d have to crack it open and inspect it. Either water got in or it didn’t. Its water protection is a bit better than connectors. Honestly, stripping the battery and trashing the car may be the best use of a flood car… yank out the modules for EV conversion or a fixed battery array for backup power or grid arbitrage. One major solar field in L.A. absolutely fills containers with packs out of wrecked Nissan Leafs for that purpose, I’m sure he’d love to receive 1000 Leaf flood cars.

Keagan said:
What destroys flood cars is in two groups.

The interior is easy to describe, it gets wrecked with mold and nasty smells that pop up on humid days.

The mechanical killer is wiring. Every wiring connection in the car has gaskets to keep out splashing rain. Go pay $2 to go into a pick-n-pull sometime and just go around disconnecting connectors and look at how they’re made.

The problem is water has weight. Every 2 feet of water depth increase pressure by 1 PSI, or about 20 kPA per metre if you’re batting on that team. So 2.5 inches of covery is still 0.1 PSI, and that’s enough to push dank flood water right past those gaskets and into the interior of the connector where the contacts are.

However, the gaskets do a bang-up job of preventing the water from leaving! Thus they entrap the water and sit there corroding, corroding, corroding.

Now electronics are a different deal, either they get absolutely wrecked due to what corrosion does to a circuit board, or they are immune because they are “potted” (dipped in epoxy) But if the connector on their edge is corroded out, it’s just as bad.

Keep in mind, wiring harnesses are no joke. They are expensive kit - either to buy new or painstakingly remove from a wreck without damage. So the harnesses themselves are a “component” that can fail.

Add to it, the failures won’t be “dead car”, but rather “mysterious niggling malfunctions that take hours of expensive technician time to chase down”, and then an endless stream of problems like this. Because the troubleshooting trees are written assuming normal failure probabilities, not the most likely culprit is a connector.

If I had a flood car, I would deconstruct it, and painstakingly inspect every component. That’s a huge amount of work even for me, a DIYer, so the economics of it are pretty dubious.

Notice I haven’t said a solitary thing about ICE engine or transmission. Those might get off scot-free, with repeated vigorous oil changes. Worst case they need a conventional teardown/reassembly to polish up metal parts, replace gaskets etc.

The big battery, you’d have to crack it open and inspect it. Either water got in or it didn’t. Its water protection is a bit better than connectors. Honestly, stripping the battery and trashing the car may be the best use of a flood car… yank out the modules for EV conversion or a fixed battery array for backup power or grid arbitrage. One major solar field in L.A. absolutely fills containers with packs out of wrecked Nissan Leafs for that purpose, I’m sure he’d love to receive 1000 Leaf flood cars.

one thing you got wrong: inside connectors are NOT watertight. water inside a car is a disaster as it will corrode every connector it touches.

Doesn’t matter the HV components are rated to whatever water resistant level, your LV system isn’t. Your modules, cabin stuff, ADAS stuff are still just the same standard stuff as an ICE. In a flood car those are your main issues. Which apply to EVs as well.

So what will happen?

  1. The car just wouldn’t function. HV components are damaged are unresellable.

  2. The car runs and drives but all the modules are soaked. This will just act like ICEs. Ticking time bomb on when those LV side of things to go wrong. Remember, loosing 12v in an EV is as dangerous as a ICE. And the EVs that I know of wouldn’t charge if 12v is too low.

So, stay away from them.

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

https://www.reddit.com/r/CyberStuck/s/jMgo5cr5Yo

Not all EVs are created equal. Buy a Rivian if you want it to survive a flood and even drive you through it. They’re sealed up to 43 inches and designed to off-road through water.

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

Most things don’t handle flood events well–even boats.

Harlan said:

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

Most things don’t handle flood events well–even boats.

when you buy the boat :smiley:

owning the boat D:

selling the boat :smiley:

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

EV/ICE is just a drive train. Flooded cars are usually totaled.

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

Is there anything that handles flood damage well? :thinking: maybe ducks? :duck:

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

If you want to know go watch some of RichRebuilds videos on YouTube. He has brought a could of flooded EV’s back to life but not easily.

Zenith said:

Lin said:
Back in the days post-Katrina, the used car market was flooded with “Katrina cars” that were basically written off by insurance companies, but then resold elsewhere, and said to be plagued by longterm electrical issues.

Very few EVs back then, and I got to thinking, how would an EV handle flooding?

My prior is that it would short out hard and be unresellable, but was wondering if it managed to stay working whether it would have longterm effects like the waterlogged ICE vehicles seemed to.

Is this a thing people who are looking to buy Used EVs need to be watchful for? Or probably not?

Thanks for reading.

If you want to know go watch some of RichRebuilds videos on YouTube. He has brought a could of flooded EV’s back to life but not easily.

good to know, YT ppl fixing things is kind of my jam, so appreciate the recommendation