Comment on Tesla Cybertruck gets less than 80% of advertised range in YouTuber’s test

• skysurfer@lemmy.world ⁨5⁩ ⁨months⁩ ago

  Due to electric drivetrains having minimal fixed losses at low speed unlike internal combustion engines. Aerodynamic losses start becoming the largest factor for EVs at relatively low speeds (25-35 MPH) since other losses at so low. This shows up on tests as higher city efficiency and lower highway.

  For an internal combustion engine you are burning a large amount of energy just to keep the engine running, so the slower the speed, the less distance traveled for the fixed amount of running losses and lower the MPG. It isn’t until higher speeds (55-65 MPH) that aerodynamic losses become the largest factor. This manifests as lower efficiency in the city tests and higher highway.

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  • Nollij@sopuli.xyz ⁨5⁩ ⁨months⁩ ago

    It’s also a factor that acceleration/deceleration in an ICE kills mileage. Highway tests maintain a constant speed. If you ran the same test at 35 mph, they would get much better mileage than at 55 (or 70)

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  • flyingjake@lemmy.one ⁨5⁩ ⁨months⁩ ago

    Idle losses are real but not very substantial in a modern engine compared to the bigger factor you’re missing which is that in city driving tests there is a lot of speeding up and slowing down, ICE vehicles throw away all the energy used to slow down as heat in the brakes which makes city cycles particularly inefficient while an EV captures that energy through regenerative braking, dramatically reducing the net cost of those momentum changes.

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    • snowe@programming.dev ⁨5⁩ ⁨months⁩ ago

      Regenerative braking only can recapture something like 2-5% of lost energy. The bigger factor is exactly what the other person said.

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      • murderisbad@lemm.ee ⁨5⁩ ⁨months⁩ ago

        This is just not true. Regenerative braking is much more efficient than that.

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    • skysurfer@lemmy.world ⁨5⁩ ⁨months⁩ ago

      Ah, good point, the speed changes for ICE ended results in lots of energy wastes due to heat instead of being recaptured. That would certainly be the largest loss for an ICE in the city cycle.

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  • ABCDE@lemmy.world ⁨5⁩ ⁨months⁩ ago

    That makes sense, thanks.

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• Critical_Insight@feddit.uk ⁨5⁩ ⁨months⁩ ago

  It has the aerodynamics of a brick

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  • TheIllustrativeMan@lemmy.world ⁨5⁩ ⁨months⁩ ago

    So does the EV9, but it exceeded the EPA range in the same test.

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    • Critical_Insight@feddit.uk ⁨5⁩ ⁨months⁩ ago

      This was a highway test though, not how EPA test the ranges

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      • TheIllustrativeMan@lemmy.world ⁨5⁩ ⁨months⁩ ago

        I know. But this YouTube channel, Out of Spec, runs this exact same 70mph loop in every EV. A large number of them exceed their EPA rated range in this test. I mentioned the EV9 because it’s similar to the Cybertruck in many ways (a brick…), and I had just watched that range test this week.

        Also worth noting the guy is a Tesla fanboy, so he’s not going to deliberately make the CT look bad.

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  • ABCDE@lemmy.world ⁨5⁩ ⁨months⁩ ago

    Aha yes, but what about other EVs?

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• statue_smudge@lemmy.world ⁨5⁩ ⁨months⁩ ago

  There’s more air resistance at higher speeds.

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  • ABCDE@lemmy.world ⁨5⁩ ⁨months⁩ ago

    That doesn’t explain why ICE vehicles are much better efficiency-wise than EV ones at higher speeds, just why EVs don’t do so well. Another post responding to me addresses it well.

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    • Nollij@sopuli.xyz ⁨5⁩ ⁨months⁩ ago

      Do you mean that ICE is more efficient than EV at higher speeds, or that ICE scales better than EV?

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      • ABCDE@lemmy.world ⁨5⁩ ⁨months⁩ ago

        ICE vehicles have better MPG at higher speeds, EVs at lower speeds.

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      • privatizetwiddle@lemmy.sdf.org ⁨5⁩ ⁨months⁩ ago

        Neither. ICE reaches its best efficiency at higher speeds than EV does, but it is still less efficient than EV at all speeds.

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• WaterWaiver@aussie.zone ⁨5⁩ ⁨months⁩ ago

  Aerodynamic drag increases with the square of speed. All cars have a different optimum speed for maximum range (which depends on wind speed & temperature too).

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• eatfudd@lemm.ee ⁨5⁩ ⁨months⁩ ago

  Air drag

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