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Freaking Fast

crgildart

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How much do these batteries weigh? Is it enough to wear down the tires significantly faster than a comparable ICE vehicle? This would be especially relevant for snow tires right??
 

dbostedo

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How much do these batteries weigh? Is it enough to wear down the tires significantly faster than a comparable ICE vehicle? This would be especially relevant for snow tires right??
Which batteries? Are you talking about the McMurtry? It weighs ~1000 kg (~2205 lbs) so not at all heavy compared to an average street car. F1 cars weigh a bit under 800 kg, NASCAR cars weigh more like 1500 kg. Other race cars are mostly in between.
 
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cantunamunch

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How much do these batteries weigh? Is it enough to wear down the tires significantly faster than a comparable ICE vehicle? This would be especially relevant for snow tires right??

Depends on the overall capacity (kWh). The SuperVan 4 is quoted at 50kWh vs. the E-Transit's 68kWh.

Depending on the exact battery chemistry we're looking at 150 - 200 Wh per kilogram for lithium (more is possible and even likely for a demo vehicle like SuperVan4)

Let's say 220 for the SuperVan and 180 for the E-Transit. I therefore guesstimate the SV battery at 500lbs and the E-Transit's at 830lbs.

In other words, short-range battery packs weigh about as much as a V8 ICE
 

scott43

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Yeah the Tesla batt packs weigh about 1200lbs. Plus the motor. But factor in a full tank, it's more but not that much more. And it's low down weight..
 

cantunamunch

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Yeah the Tesla batt packs weigh about 1200lbs. Plus the motor. But factor in a full tank, it's more but not that much more. And it's low down weight..

Those are 100kWh, right? About 183 Wh/kg, i.e. approx the same energy density as I'm assuming for the streetable E-Transit? Except double the presumed range of the demo SuperVan :roflmao:
 

cantunamunch

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So why not just point the fans in the direction you want the car to accelerate? Or large vertical wings? Why must everything go through the tires?

The answer, in the specific case of the Speirling, is that they're designing the fans for lowest possible power draw and lowest possible net air flow.

Practically speaking, the less air they draw through the less road crap gets taken up by the air filter, and once the target vacuum is a achieved the power draw is only as much as needs to correct for seal imperfections.

Theoretically speaking, the tires are *much* more efficient than fans at energy transfer, especially transferring energy to masses of air comparable to the mass of the car.

(I assume everyone in this thread knows the meaning of the word 'speir' by now)
 

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