This latest Tesla fire shows once again that water and electricity does not mix well after all.
Oft-opinionated Tesla CEO has in the past been known to promote its EVs to be capable of turning into boats for short periods of time. In fact, here is a verbatim quote from Mr. Musk about this exact topic regarding its soon-to-be-launched all-electric pickup:
Cybertruck will be waterproof enough to serve briefly as a boat, so it can cross rivers, lakes & even seas that aren’t too choppy
— Elon Musk (@elonmusk) September 29, 2022
Though much like the things that have been tweeted (or perhaps now better known as X-ed) from the hands of Elon, it might not be entirely wise to take his word as gospel. Such is especially because there was recently an incident in which a Model X caught fire after backing down a boat ramp, and perhaps scarily still continued to burn while being completely submerged in the water.
Well, to be completely fair to Mr. Musk, it is worth highlighting here that there may have be some failure that occurred prior the vehicle entered the water. Hence his claims of Teslas being able to be turned into boats might actually (to pardon the pun) hold water.
Having said that however, as this rather good video summarising the incident below explains, it is still perhaps not wise to turn a Tesla into a temporary boat, or in fact get it close to any salt water. What more too is that this is apparently not to be the first time an EV has continued burning under water, with apparently two prior well-documented incidents of these submerged combustions occurring globally.
Now for those who don’t feel like sparing the four minutes on the video above though, here is a TL;DR on what has transpired with this particular Tesla fire under water, in addition to why EVs can still burn while submerged.
Starting with the story about this particular submerged Tesla first, a report by Hollywood Fire Rescue of Hollywood, Florida stated that the Model X was attempting to back a jet ski into the water at the Polk Street boat ramp, when it lost traction and slid into the inter-coastal. The report then continued to state for the salt water to have reacted with the the vehicle’s electronics, causing them to short and thus sparking a fire that burned underwater for an extended period of time. It was then added that the firefighters allowed car to burn under water until it was complete, before extracting the vehicle onto land.
Moving onto why an EV can combust even in the water meanwhile, it is hypothesised in the video for the water to gain entry into the normally water-tight battery box through the in-built pressure regulation vents. Said water ingress then could cause a short within the battery, which initiates the thermal runaway reaction of the cells. The chemistry of the battery too is such that it does not need oxygen to combust, hence it can still burn while under water.
All said though, it is probably still (with the right precautions) be alright for Teslas to drive in the rain, and perhaps even the odd mildly flooded bit of road too. Thinking that an EV doesn’t have to breathe air for it to operate and then driving it into a lake on Mr. Musk’s word should however only be left for his cultists who don’t mind buying another car soon after.