Comment on xkcd #2929: Good and Bad Ideas
frezik@midwest.social 1 week agoThe sun gives you around 1500W per m2. If sun shines at maximum brightness for 24 hours, you get 36kwh per day. That’s enough to fully charge a small EV every day.
Bringing this to numbers that exist in the real world, the sun will only give you about 20% of that over the course of the day, and the panels are around 20% efficient. You’ll get more like 1.4kwh per day per m2. You can double or triple that, depending on how much surface area you can cover. An EV can get around 3 miles per kwh, so even tripling that number can get you 12 miles. Considering the extra costs involved (both in buying the panels and adding weight), it’s not even worth it as a supplementary source.
Put the solar panels over the parking places and roadways, not on the cars.
jmiller@lemm.ee 1 week ago
The benefits increase as the efficiency of the car increases though, check out Aptera. They say they get 10 miles per kwh, and they have a lot of surface area for panels. Enough that in ideal conditions they say they get 40 miles per day from solar. It is a bit different looking though.
aptera.us
frezik@midwest.social 1 week ago
It’s also a three-wheeler, which gets around US safety regulations. It gets registered as a motorcycle or autocycle (depending on how your state handles it). However, it’s still an enclosed metal box. There’s not a lot of good data, but it’s arguably better to be sitting loose on a motorcycle with a helmet and safety gear as opposed to being crushed inside a sardine can.
There’s a certain point of shrinking cars where you have to ask “why not use an e-bike?”, and this is that point.
jmiller@lemm.ee 1 week ago
Well, it has a carbon fiber frame with a crumple zone in the front. They are going to put it through 3rd party safety testing. It won’t be as safe as a big SUV, sure, but I think it will be safer than an ebike. It also protects you from weather and has 35 cubic feet of storage in the back. I think ebikes are great too, but this does have more of the advantages of a car.
frezik@midwest.social 1 week ago
You know how the Internet made fun of Stockton Rush for using carbon fiber in a sub, which is a compression structure? Similar thing going on here. Carbon fiber is a great material for tensile strength and lightweight. It can be used in compression structures, but it needs more careful engineering to pull it off. The benefits do not always outweigh the costs.
As a more general issue, if a car the size of a Geo Metro or smaller can’t be safe on roads, then motorcycles and bikes can’t be, either.
Fenrisulfir@lemmy.ca 1 week ago
Cuz you can haul more, camp inside of it with the tent mod, travel further and faster.
frezik@midwest.social 1 week ago
I’m not sure you can haul more. Cargo e-bikes can do a lot more than you think.