21–30 of 919 posts
Why does 500wh/kg make electric aircraft possible? 6x less than kerosene. Is that the break even on cost if you can source very cheap electricity? Seems like it would still annihilate the payload/range.
Seems like marketing hype to me. An 8-hour transatlantic flight requires something like 600MWhr of energy. That's about 75MW, which is in small nuclear reactor territory.
Why does 500wh/kg make electric aircraft possible? 6x less than kerosene. Is that the break even on cost if you can source very cheap electricity? Seems like it would still annihilate the payload/range.
Why does 500wh/kg make electric aircraft possible? 6x less than kerosene. Is that the break even on cost if you can source very cheap electricity? Seems like it would still annihilate the payload/range.
> Why does 500wh/kg make electric aircraft possible? 6x less than kerosene Where did you read that kerosene is at 3000Wh/kg? My googling says 12,000Wh/kg The tweet thread from TFA and its replies just says that for aircraft, weight impact is important. See https://twitter.com/__bdimitrov__/status/1298753593638440960 : "260 to 400 Wh/kg should lengthen flight time by 90.8% --- assuming that 100% of the drone weight is…
"CATL has announced a new “condensed” battery with 500 Wh/kg which it says will go into mass production this year" This is a lot more credible than most of the battery stories, because CATL is already producing a ton of batteries, lending them some credibility. This is a little under 2x the density of current batteries.
The exciting part of this announcement is that if anyone can scale manufacturing, it is them.
Why does 500wh/kg make electric aircraft possible? 6x less than kerosene. Is that the break even on cost if you can source very cheap electricity? Seems like it would still annihilate the payload/range.
Yep. Also... kerosene gets spent. Pilots can also dump fuel in emergency when it's too heavy to land. Battery powered planes can't dump electricity, so I'd imagine some trade offs that have to be made.
Also, this could be interesting already for existing small and/or short range airplanes like Pipistrel‘s training aircraft or Eviation‘s Alice. I don‘t know the energy density of their current batteries, but this could give them a boost very soon.
"CATL has announced a new “condensed” battery with 500 Wh/kg which it says will go into mass production this year" This is a lot more credible than most of the battery stories, because CATL is already producing a ton of batteries, lending them some credibility. This is a little under 2x the density of current batteries.
Current mass produced batteries, which tend to hover around 260-300 Wh/kg. Higher density (but still under 500) are available, but in far smaller quantities for a very high cost. The exciting part of this announcement is that if anyone can scale manufacturing, it is them.
Reminds me of the "revolutionary battery checklist": https://news.ycombinator.com/item?id=28025930
edit: removed the paste of the checklist because of spam.
"CATL has announced a new “condensed” battery with 500 Wh/kg which it says will go into mass production this year" This is a lot more credible than most of the battery stories, because CATL is already producing a ton of batteries, lending them some credibility. This is a little under 2x the density of current batteries.
> What makes CATL’s announcement this week truly groundbreaking is that the condensed battery will go into mass production this year.
Why does 500wh/kg make electric aircraft possible? 6x less than kerosene. Is that the break even on cost if you can source very cheap electricity? Seems like it would still annihilate the payload/range.
Let's consider Cessna-172S ([4]). Its characteristics: - 130 kW engine, Lycoming_O-360 that weighs 117 kg. For comparison, an electric motor of this range would weigh 11-13 kg (at 10-12 kW/kg, [2]). That saves 100+ kg weight immediately and we can put 50+ kWh batteries instead. - It carries up to 200 liters of kerosene ([3]), which weighs 164 kg. We can place 82 kWh of batteries instead. - The engine consumes around…
I also think taking out the weight of the tank is unfair if you don’t add weight for the structures for holding the batteries.
But yes, for many smaller planes, we’re close to flying electric on shorter flights being economically feasible.
Why does 500wh/kg make electric aircraft possible? 6x less than kerosene. Is that the break even on cost if you can source very cheap electricity? Seems like it would still annihilate the payload/range.