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>Meanwhile, gasoline / petrol / benzin (wherever your are in the world) has an energy density of 12200 Wh/kg. Electric motors are 90% efficient, ICE are less t
by tenuousemphasis 6y ago
>Meanwhile, gasoline / petrol / benzin (wherever your are in the world) has an energy density of 12200 Wh/kg.
Electric motors are 90% efficient, ICE are less than 20%. So in reality gasoline is 2-3x as energy dense, when you look at how much of the fuel's energy can be used to do useful work.
- tengbretson 6y agoYou also have to factor in the weight reduction as petroleum fuel is consumed vs the fixed weight of a battery.
- Tuna-Fish 6y agoTrue, but the effect of this is less than it sounds like, as while the fuel is consumed, in an ICE car the engine is the heavy part and that isn't consumed.
- klyrs 6y agoDon't discount this so easily. You can't land a jumbo jet immediately after takeoff because its maximum allowed landing weight is much less than its maximum allowed takeoff weight. So you'll need a stronger fuselage and landing gear for electric plans, which means even more weight
- tenuousemphasis 6y agoYes, that's true. And the cost of electricity vs. fuel. Safety is another factor. The point is there's a lot more to it than Wh/kg of the energy source.
- outworlder 6y agoThis is a huge deal for aircraft. Not much for cars, as EVs are not carrying a lot of extra baggage that ICE cars require. When was the last time you saw an ICE with both a trunk and a frunk? :)
- throwaway189262 6y agoModern gasoline engines are not as heavy as you may think. I once transported 2 liter car engine in the back seat of my civic. Only ~150 lb and quite manageable. Even monster SUV motors are only ~350 lbs. That doesn't include cooling, oil, accessories, or transmission but EV's have those too.
- ScottBurson 6y ago> When was the last time you saw an ICE with both a trunk and a frunk? Seconds ago -- there's one in my carport :-) (A 1993 Toyota MR2; it's mid-engine. The frunk is small, and completely filled by the spare tire and aftermarket stereo amp.)
- gibolt 6y agoI'd love to see a future where part of a plane's battery pack is a detachable drone that could fly back right after takeoff (most taxing on energy use) and thus decrease the weight of the plane. You could also have battery swaps during flight as they pass over drone battery depots. Sounds crazy. Might not be worth the gains for the complexity, but could be worth it across a whole fleet. Microwave laser groundstations (or solar satellites) could come first, removing much of the battery requirement.
- tengbretson 6y agoHah, now you've got me imagining a gentle rain of 18650 batteries following a plane as it travels across the sky.
- gibolt 6y agoYes, gentle :D
- mikeyouse 6y agoSeems like you'd be better off with a ground-based catapult system to get the plane up to speed and in the air where the on-board motors could take over.
- gibolt 6y agoIf these are passenger aircraft, that probably wouldn't fly
- microcolonel 6y ago> If these are passenger aircraft, that probably wouldn't fly Well, it doesn't need to have the same rate of acceleration as a carrier's, but honestly it just doesn't make sense in general.
- mikeyouse 6y ago
- oh_sigh 6y agoMy SUV is 4500 lbs and has a 17 gallon tank. Gasoline weighs ~6lbs/gallon, so it only factors for about 2% of total mass between a full and empty tank. Seems safe to mostly ignore it.
- throwaway189262 6y agoElectric vehicles have range problems in cold climates because you don't have waste heat. On a very cold day 60% of that waste heat might be used to warm the cabin. This translates to up to 50% range reduction in electric vehicles.
- DarmokJalad1701 6y agoThis is a myth. It is not nearly that bad. I own a Model 3 in a place where it is frequently below 30F in the winter. My last road trip when it was 17F throughout I consistently got around ~250-270 miles out of 310 rated range. The new hybrid heat-pump based system in the newer models makes it even more efficient.
- throwaway189262 6y agoIsn't the range penalty a lot worse on short trips? When I was researching Leaf I noped out of buying one because range penalty in the cold for daily commutes was almost 50%
- DarmokJalad1701 6y agoDepends on the generation of Leaf. The older ones had a big problem with thermal management. Teslas on the other hand has a cooling loop that takes in excess heat from the motor (in some cases, intentionally running the motor inefficiently to generate more heat), to "condition" the battery to the ideal temp. Ideally this is done while plugged in if for short trips. The car essentially stalls the motor with just enough current to generate heat. On long trips, the heat generated during the drive is enough to take care of this and the battery stays at the optimum temperature even if it is extremely cold outside.
- hansvm 6y agoI'm not sure how much it would matter, but it's probably worth pointing out that 17F is nearly shorts weather in the middle of the brutally cold winters a lot of places experience.