Cars, of all kinds, can be dangerous. Gasoline cars are filled with highly flammable liquids and hot bits that move really fast. Electric cars are full of unholy trapped lightning. But where does rational caution stop and fear mongering begin? Let’s see if we can figure this out.
I’m writing this at all because of this recent post from nanoFlowcell, The Spectre of High Voltage. Down with the Volts! Their blog post is strongly suggesting that high-voltage electric cars – including Teslas and pretty much every other one – are something you should panic about:
To put it another way: up to 600 volts now flow through the wiring looms in modern electric vehicles. And it is precisely this fact that makes electric cars such a spectre of fear for many drivers. Negative headlines like those on the up-and-coming Tesla Model S foment scepticism concerning an otherwise advanced automotive drive technology.
We’ve written about nanoFlowcell before, a three-year-old electric car company from Lichtenstein that has made a few sleek-looking electric show cars that they claim run on a replaceable-electrolyte flow batteries that can use “salt water.” Their fundamental technology seems pretty suspect, but we don’t know anything for sure because they’ve neither released relevant details about their tech nor let a working car into the hands of anyone.
They’ve yet to produce any actual proof that their low-voltage flow-battery systems work, but that doesn’t mean they’re not keeping busy. They are producing some fear-mongering blog posts that feel a lot like the early days of electricity, and the Edison-Westinghouse “War of Currents.” There are certainly valid points in the posts, but overall it really feels like they’re trying to make people afraid of now-mainstream electric cars like the Tesla.
I’ve reached out to nanoFlowcell for comment, but have yet to hear back.
The cars built by nanoFlowcell – well, the cars that hypothetically would be built by nanoFlowcell, since they only just make the occasional show car that no one ever really gets to drive – are designed using a low-voltage electrical system. Their recent show car, the Quantino, for example, uses a 48V electrical system.
Most modern electric cars, however, work with much higher voltages: according to Tesla’s First Responder Guide, for example, the Model S’s battery-powered high-voltage system is 400V.
The suggestion from their blog post is that not only will backyard mechanics be unable to work on modern electric cars, if they try, they might end up dead:
The times when hobbyists tinkered with their cars in rented garage space are well and truly over with the advent of the electric car. Back in the day, you might have burnt a finger on a hot engine, but direct contact with up to 600 volts - 2.5 times that from a domestic outlet - means danger to life and limb. Maintenance work on the high-voltage system of an electric vehicle is thus the exclusive preserve of trained workshop experts, specifically schooled in the dangers of working on high-voltage vehicles.
Not surprisingly, nanoFlowcell has a solution:
With low-voltage systems that operate at just 48 volts instead of up to 600 volts, car makers would be able to work without many of the currently necessary HV safety precautions and their associated disadvantages. And if low-voltage technology were to be paired with nanoFlowcell technology, an electric car would not need to be any more expensive than a conventional vehicle with an internal combustion engine.
So, how much of this is real, and how much is bullshit? I mean, it’s no secret that a jolt of 400V is no picnic, but there’s an awful lot here that’s not being said. Like, for example, how does a 48V electric car perform the same as a 400V car? Is that possible?
The answer is, sure, sorta. See, it’s not all about the voltage. To get an electric car moving at a sustained, say 60 MPH, you need the same amount of power, regardless of what voltage you’re using. That amount is around 24000 watts.
The way you get that amount of power at both 48V and 400V has to do with how many amps you’re using. A 48V system isn’t magically using less power to move a heavy car at a mile a minute– it’s just making a bigger pipe, if we use the volts as how fast electricity is flowing through, and amps as how much is flowing through, according to the old electricity-as-water-in-a-pipe-analogy.
So, at 400V, you’ll need equipment that can support 60 amps, and at 48V, you’ll need equipment that can support 500 amps. Wiring and motors and other equipment that works at those really high amperages need to be very heavy and robust. They also generate an awful lot of heat.
The reason that most modern electric cars choose high voltage over high amps is that the equipment is smaller and lighter, easier to cool, and thus more efficient. A 500 amp motor running at 60 MPH will overheat pretty damn quickly. There’s a great discussion of this on this DIY electric car-makers forum.
Now, here’s the real question: is a jolt from a high-voltage/low-amp system that much more dangerous than a jolt from a low-voltage/high-amp system?
The answer is actually surprisingly tricky to find out. After a lot of confusing and conflicting Googling, talking to engineers, and wading through a lot of jargon, I decided to call an expert. I found one, a professor at the University of San Diego, who specializes in electrical injuries. His name is Dr. Michael Morse.
Dr. Morse confirmed that, yes, a high-voltage shock (like in dealing with a Tesla) is far more dangerous, and much more likely to electrocute you. While it would absolutely be bad to have a very high-amp current pumping through your body, the good news is your body simply isn’t drawing a high current.
It’s like this: the battery pack in a theoretical nanoFlowcell system may be 48V and have the capability to deliver 500 amps, and while the motors will pull that level of amperage out of the battery, your body, not being a powerful electric motor, won’t. You’ll get a 48V shock, which won’t be a tickle, but it’s not going to kill you.
Now, that said, this does not mean that low-voltage electric cars are completely safe. High-amperage electrical systems can create a lot of heat, and in a context of a home repair or an accident, I think an unnoticed short is as likely to happen as an accidental shock, and a high-amp system with a short will get hot enough to become a fireball quicker than a high-voltage/low-amp system.
Look what happened to our own David Tracy with a low-voltage (12V) but high-amp (several hundred amps capable) car battery when he let some wire short across the battery terminals while trying to, um, cook on his engine.
That’s much fewer volts and amps, and it managed to heat a wire hot enough to melt into David’s hand. nanoFlowcell’s system may not kill you with electricity, but there’s no reason it couldn’t kill you with fire.
Again, getting shocked by any high-power system like you’d find in an electric car – low or high voltage – is bad news. Maybe nanoFlowcell has some magic low-current/low-voltage system that is somehow efficient and usable in a car. If that’s the case, I’ll happily apologize.
But that would mean they’d actually have to tell us how their system works, which, so far, they’ve not been inclined to do.
Also, they’re making one big-ass assumption about backyard mechanics working on electric cars: that they’re morons.
When you work on your house’s wiring, unless you like the idea of getting flung into a wall and feeling like a thousand tiny vibrating worms are burrowing into your body, you shut off the power. I’m pretty sure anyone who wants to try to work on an electric car would take similar steps. Mistakes can happen, sure, but there’s a rich panoply of ways to get hurt working on conventional gas cars as well.
Also, pretty much every electrocution situation they discuss relating to high-voltage electric cars could also translate into a fiery death in a high-amp car. At best, it seems like they’re just swapping one kind of death for another.
Point is, nanoFlowcell is pushing some fear-mongering bullshit here, and it reminds me of the days when Thomas Edison would round up stray pets to electrocute them in front of people to show AC (high voltage) power was dangerous.
Working on combustion cars can be dangerous, working on electric cars is dangerous, and that’s just how it is. Carmakers are already doing all they can to make electric cars safer in accidents and safe to work on, but there will never be zero risk.
If nanoFlowcell wants to be a real player in the electric car field, they need to let some of us journalists try out their cars, and see if the claims they make have any basis in reality. If trying to scare everyone away from Leafs and Teslas is their best plan, I’m not so confident about their chances.