http://www.digitaljournal.com/tech-and-science/technology/electric-cars-and-floods/article/533322

Electric cars and floods — not like peas and carrots

Posted Sep 29, 2018 by Ken Hanly
After Hurricane Florence dumped more than two feet of rain in parts of North Carolina people may be wondering what happens to electric cars (EV) in floods and afterwards. This is of particular concern to EV owners.
As of December 2016  the Nissan Leaf is the world s all-time best-selling electric car with more tha...
As of December 2016, the Nissan Leaf is the world's all-time best-selling electric car with more than 250,000 units sold since 2010.
Mic from Reading - Berkshire, United Kingdom (CC BY 2.0)
Flood damage to an electric car depends upon conditions
Different people gave different answers.
You Tube user Rich Rebuilds, rebuilt a Tesla Model S he bought for $14,000 that had been flooded by Hurricane Sandy in New Jersey back in 2012. The entire battery, motor, and all the drive electronics had been sitting in salt water in the bottom 14 inches of the car. The model S was a total insurance loss.
Rich has a multi-part series of his trials and tribulations rebuilding the car. He found he could not buy parts from Tesla and he also discovered that the car was in salt water that would cause much more damage than fresh water. Below I have appended the first part of his series.
When dismantling the car Rich found that after sitting in the salt water, the battery pack was waterlogged. 12 of 16 modules in the pack were OK. However, one of the four that were not, was so corroded that it began exploding as Rich took it apart.
Rich did manage to finally rebuild the Tesla. A bear for punishment, he undertook to repair another one but this one from fresh water and he had less trouble as shown on the appended video. He made sure the fuse was removed so that he would not be exposed to high voltage. Rich has a warning on his videos not to try this at home but leave it to the experts. Do as he says not as he does!
Jeff Wandell, the EV spokesperson for Nissan said that in their EV's the high-voltage components such as the battery, traction motor, and inverter are all waterproof claiming :"So no need to rebuild or replace the battery pack."
One expert said that lithium is highly flammable. When it does catch fire it produces great heat when exposed to water. However, battery cells are usually sealed and water tight. However, it is larger packs and wiring that can become waterlogged and damaged in some cars. Wiring harnesses and electronic circuit boards can be corroded. Even if they work at first, their lifespan can be significantly shortened. Beyond this, electric cars suffer the same sorts of damages from a flood and water than any other car.
How to tell if a car is water damaged
If there has been water in the carpets, seats, seat belts, or other soft parts, mold can develop. This can become a breathing hazard. Damage to cars that have been in salt water is often much greater than in fresh water but both are damaging.
When buying an EV that may have been subject to flood damage check the seat tracks, also the head of hidden screws under the dash to see if there is corrosion. Look under the carpets, and behind taillights for muddy residue which are sure signs that the car has been submerged.
Special arrangements for EV's during hurricane Florence
The mass evacuations caused by Florence create special difficulties for those with EVs, especially older models that have a relatively short range. These may require several charges before they are out of danger of the huge hurricane. Chargers on the way out of the area may become crowded and the hurricane force winds and rains may make some of them inoperable.
Lanny Hartmann a Baltimore Maryland EV enthusiast devoted part of his EV website, PluginSites.org to helping evacuees with EVs while the storm lasted. His site included storm advisories, news reports, and reports of places where evacuees could stay, as well as special information to help EV owners evacuating.
One such piece of information was a notice from Tesla that said: "We are temporarily enabling your car to access additional battery capacity, as well as free Supercharging, in preparation for Hurricane Florence. We hope that this gives you the peace of mind to get to a safe location, and will notify you before returning your car to its original configuration in mid-October. Badging on your display may adjust during this period. Safe travels!"