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BYD Reveals the ‘World’s Longest-Range EV’ as American Auto Industry Struggles to Keep Pace (gizmodo.com)
submitted 6 months ago by to c/technology@lemmy.world
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[–] 8 points 6 months ago (2 children)

Adding more batteries increases the weight, though, which in turn makes the motors work harder, and therefore makes them use more energy to do the same thing.

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  • [–] 4 points 6 months ago (2 children)

    That's not that big of a deal for long-range trips, on which you typically don't have to accelarate often.
    Keeping the car going at a certain speed depends on several types of resistance, most importantly air resistance, but not really on weight.
    More weight plays a bigger role for energy consumption in urban ares, where the weight needs to be accelerated more often than on the highway, the mileage per kWh is yet typically higher than on the highway due to the lower speed and less air resistance.
    What I'm trying to say: I'd pick the bigger battery any time over the smaller one, if the price is reasonable.
    EVs are already heavy. The weight from some additional batteries don't play a big role.

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  • [–] 3 points 6 months ago (1 child)

    Also, with breaking recovering energy, this negates some of the issues too. The inertia is used to recharge the batteries, so the losses are from friction and heat losses. Obviously lighter is better, but a lot of the issues of weight on efficiency can be reduced. Weight is bad for safety though, so there is that to consider.

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  • [–] 6 points 6 months ago

    It sure does. But we have to consider that recharging is less efficient than not spending the energy on acceleration in the first place, so heavier EVs are worse off than lighter ones; it's not only losses from friction and heat losses - those come on top.
    And you're spot-on with the danger that comes from weight; being in an accident with a lot of kinetic energy that needs to be absorbed is not great.

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  • [–] 1 point 6 months ago* (1 child)

    Frequent acceleration/deceleration driving like city driving is also significantly more efficient in EVs because of regenerative braking. ICE just lose all that energy they spent accelerating when the have to stop 500m later, which destroys their efficiency.

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  • [–] 3 points 6 months ago

    I was comparing EVs with different weight and not comparing EVs with ICE vehicles, though.
    And in that case the heavier EVs are less efficient than more leightweight versions even with regenerative breaking, because the process of accelerating and breaking cant' regenerate all energy that was spent for accelerating.

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  • [–] 1 point 6 months ago

    It's the same idea as adding a larger gas tank. If you wanted to make a gas car go 600mi, you'd just need to hold enough gas to double the range + make up for the load of the extra gas itself, of course as the tank depletes, it gets markedly lighter.

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