[capableweb]

I think even with a 50% weight reduction for the same amount of energy, it still doesn't come close to the energy density of jet fuel.

And furthermore, there are more things to consider than just the energy itself, if we want to deploy it widely. Things like charging time, changing existing infrastructure, costs for R&D and development and finally all the regulatory approvals you'd have to go through. Of course not impossible but I think we're still really far away from making it happen.

[cyberlurker]

In regards to charging time, I would think physically switching batteries to a charged one (or many) would make a lot of sense. Just a new form of the current refueling process airplanes go through now.

[cogman10]

Most batteries have ~1C charging time (Which translates to being able to go from 0% SoC to 100% SoC in 1 hour).

For most flights, you are looking to anywhere from 1 to 2 hours to get a plane ready for the next flight. Plenty of time to plug it in and charge it up.

The bigger problem would be delivering the massive amount of juice needed to charge a plane up in that time frame. For that, maybe it would make sense to swap batteries and have some on reserve.

[throitallaway]

We just need to line the fuselage (or make it out of) batteries.

[labcomputer]

The problem is that airplanes cost energy to stay in the air. There’s a well-known relation that an airplane operated at best economy (most are) costs ~0.4kWh/ton-km [1]. That per ton of total mass in the sky.

So the problem is that, with current battery technology, the total weight of a battery electric plane is around 3x that of a fossil plane[2]. Taking into account typical efficiency, that means a battery plane requires more energy to move a given amount of cargo a given distance.

And that’s with using relatively ancient fossil fuel engines. Unless batteries get markedly better, you’re better off just synthesizing liquid hydrocarbon fuel from atmospheric CO2 and solar panels.

[1] https://www.withouthotair.com/cC/page_274.shtml

[2] I’ve seen battery conversions of a Cessna 208 and a Cessna 337. After conversion, they have roughly the same payload of a Cessna 182 and Cessna 172, respectively. The gross takeoff weight of the battery plane ends up about 2.5-3x that of the smaller fossil plane, assuming same payload and fuel to fly equivalent distance. In both instances range drops from ~800 miles to ~200.

For another example, look at the Pipistrel Velis Electro: with daytime VFR reserves, range is less than 70 miles (my estimate, because Pipistrel actually doesn’t quote a range estimate, stating that endurance for training sorties is “the appropriate parameter to quote”). A Cessna 162 has the exact same gross weight (both are LSAs), but a 38% higher rate of climb, and roughly 5x the range with same payload. Pipistrel also had to make other compromises: 162 has a 20% shorter takeoff roll and 20% lower stall speed, too.