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> This is at 66.9 km/h (40 mph) in order to greatly increase its range due to lower drag compared to normal highway speeds. > As a comparison a Tesla Model 3 g

> This is at 66.9 km/h (40 mph) in order to greatly increase its range due to lower drag compared to normal highway speeds. > As a comparison a Tesla Model 3 got 975km (606 miles) at 40 km/h (25 mph) [1]. I can't seem to find any range tests at a similar speed as the Nexo. > It doesn't seem like current fuels cell have much of a energy density / range advantage even though hydrogen itself is much more energy dense, the fuel cell weight and efficiency and high pressure liquid hydrogen tanks must be accounted for. I'm curious to know how you come to this conclusion? I don't know much about aerodynamics other than at, as a first order approximation, drag is proportional to the SQUARE of the velocity. Driving 887.5 km at an average speed of 66.9 km/h is, afaict, much more impressive than driving 975 km at 40 km/h.

SigmundA 5y ago
Drag isn't the only thing in play. They both are driving below highway speeds, one more so than the other, I wish there was some data for a Tesla at 40 mph vs 25 or 48 to compare more directly the difference. The Tesla will have between 975 and 708km range at 40 mph the NEXO is 887km, I will make an assumption the Tesla is less, but how much less, is it "much" different? What is the energy density delta between a HFCV and BEV currently?
- donaldcuckman 5y ago
  drag really is just about the only thing at play
- BombNullIsland 5y ago
  Doesn't matter much. Below about 80km/h rolling resistance is dominant. >What is the energy density delta between a HFCV and BEV currently? Depends on what you're counting. Mirai's fuel cell stack, composite overwrapped tank, additional underbody and rear impact crash protection, high pressure filling system, cooling and fan intake system, and lithium battery together masses well over 400kg. Also takes up a lot of cabin and cargo space necessitating a larger vehicle. Tesla's new 4680 batteries form part of the vehicle's structure and add free torsional rigidity, and will weigh roughly the same as a fuel system for 600km range. I imagine in the compact they'll package it into the unused area under the rear seat in order to drop the floor which should help with CdA.
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SigmundA 5y ago

Drag isn't the only thing in play. They both are driving below highway speeds, one more so than the other, I wish there was some data for a Tesla at 40 mph vs 25 or 48 to compare more directly the difference. The Tesla will have between 975 and 708km range at 40 mph the NEXO is 887km, I will make an assumption the Tesla is less, but how much less, is it "much" different? What is the energy density delta between a HFCV and BEV currently?

donaldcuckman 5y ago
drag really is just about the only thing at play
BombNullIsland 5y ago
Doesn't matter much. Below about 80km/h rolling resistance is dominant. >What is the energy density delta between a HFCV and BEV currently? Depends on what you're counting. Mirai's fuel cell stack, composite overwrapped tank, additional underbody and rear impact crash protection, high pressure filling system, cooling and fan intake system, and lithium battery together masses well over 400kg. Also takes up a lot of cabin and cargo space necessitating a larger vehicle. Tesla's new 4680 batteries form part of the vehicle's structure and add free torsional rigidity, and will weigh roughly the same as a fuel system for 600km range. I imagine in the compact they'll package it into the unused area under the rear seat in order to drop the floor which should help with CdA.

deleted 5y ago

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