alt Hacker NewsThis analysis doesn't make sense to me.
An ICE vehicle isn't less efficient because the frame itself takes more energy to move, it's less efficient because the engine burns off a high percentage of its energy as waste heat.
But that will be true regardless of what the load is. If the ICE truck takes 5 units of energy to pull itself compared with 1 unit for the electric truck, that implies that the the truck chassis only actually requires 1 unit to move, but the ICE engine burns off 80% of its energy as waste heat. The engine is only 20% efficient.
Now if you start pulling a trailer, you have (in total) 2 units of energy worth of load. But if the ICE engine is still only 20% efficient, then it will take 10 units to pull both, rather than 6.
I can believe that this effect is real (electric cars suffering more range loss when towing), but it seems to require an explanation beyond this one.
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It's the effeciency curve. ICEs are more efficient with heavier loads - more fuel goes to useful work.
There's also that electric cars have a marginally better drag coefficients for a few reasons - ICE vehicles have a bot less incentive and they need to use more air for cooling - so the drag from a trailer will be worse, as a percentage extra, on the average electric vehicle.
The range on my diesel truck drops in half when I pull my trailer. Roughly similar to an EV towing. It also happens in winter (not quite as big a drop). Thats what most folks care about. But people like to overstate it as a dramatic downside of EVs.
> This analysis doesn't make sense to me.
Because the numbers are a bit off. I've towed a lot, gas trucks do not lose 15% when towing. My old F150 went from 18mpg to 10mpg. My super duty went from 16mpg to 8mpg.
The advantage is that gas is so energy dense we just routinely equip trucks with 35+ gallon fuel tanks. There's no battery option equivalent yet.
I think what it actually says is that EV has short ranges.
If a car held gas worth of 750mi of driving and towing would reduce it to 500mi, and your actual driving distance was significantly less than both, the difference would be unnoticed.
If a car held gas worth of just 500mi with extremely well optimized aero and driveline loss minimization and highly efficient regen, and a towed trailer would absolutely ruin that, and your driving distance was too close to the diminished range, you will notice that.
If your EV held like 12500kWh of charge for like 3000 miles of range, and it was mostly for Costco runs, towing range penalties will not be among your top concerns.
It’s also the part that if you go from 400 miles to 200 miles between 5 minute gas fill ups, eh. But doubling 20-30 minute charges? Super annoying.
But boy does my model Y tow tiny trailers well.
It is more complicated with ICE though because the efficiency changes with load amount, and what power output an ICE is most efficient in can be designed with towing in mind. Ive seen 90s trucks that got 18 MPG empty on a good day, but then when loaded with twice or more the vehicle's curb weight on a trailer merely drop to 17 MPG.
Generally this is only true for ICE with an abundance of extra power to start with, but that is basically every truck and most other cars for the last 25 years.