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This is like building a gas powered car with a refinery attached to the roof. Batteries exist. Solar panels add weight and design constraints. Why is this a th

This is like building a gas powered car with a refinery attached to the roof. Batteries exist. Solar panels add weight and design constraints. Why is this a thing? What am I missing?

TeaVMFan 1mo ago
Solar panel efficiency has increased and they have made an extremely slippery vehicle. 4kWh/day and 10 miles per kWh gives 40 miles per day of driving range, enough for many people without ever plugging in.
- dymk 1mo ago
  Solar panel efficiency hasn’t gone up that much. It’s not like solar panel cars were just barely not worth it - the economics weren’t close to making sense. 10 miles/kWh is also insanely efficient, unbelievably so (well over 2x your average EV), and I don’t see where they back that claim up.
- qurren 1mo ago
  > 4kWh/day That's over-optimistic and you will probably only get that in a small handful of places in the world like the southwestern US or the Middle East and even then only for part of the year. The hot, sunny, never-cloudy parts of the world also tend to be the ones where driving long distances is most necessary.
  - vlovich123 1mo ago
    From some parts of SF to SJ is about 42 miles. Thats a very long distance that you’re likely to get completely on solar. For that long of a commute you probably need a bigger battery but you could easily have most of your costs met for free with minimal top ups. And that’s a very long daily commute. Also temperature doesn’t matter too much. You just need sun. I bet it’s enough for most of California year round with minor exceptions that you need to use infrastructure charging.
    - qurren 1mo ago
      > some parts of SF to SJ is about 42 miles. That's pendantic. Add traffic, air conditioning, a shitton of traffic lights, a restroom stop, and a detour to buy groceries on the way. Oh and if your tires are at 38 instead of 42 psi you're going to lose some range there too. And then some wind, elevation changes. Roof rack bars, because people actually do go on outdoor trips (who would have thought?) And you probably want to arrive with 10-20% left, not 0. You're quickly looking at needing 84 miles of effective range to make the 42 miles safely. 168 miles for the round trip. Yeah, shit adds up fast. My EV has a 363 mile "EPA rating" (whoever those charlatans are) but the realistic range I got from day 0 with a fresh battery in real life conditions is closer to 200-250 miles.
      - vlovich123 1mo ago
        You’re thinking of this as a primary driving vehicle. I’m thinking of it purely as a secondary commuter vehicle / renting when you need to do a longer trip. And you’ve wildly intentionally inflated your estimates precisely to make it seem insane. There’s no roof rack on this (again - commuter vehicle, not a long distance camping vehicle). Also, this is intentionally a super tight distance and very few people are actually commuting from SFO to SJC. I’m intentionally highlighting how workable 42 miles is for a daily commute. Also you should avoid keeping your roof rack on your vehicle if you don’t need it unless you’re constantly using it. They’re generally quick to take off and put on The average daily commute in the US is 10-16miles.
softwaredoug 1mo ago
You’re missing that many people do not live in single-family homes with easy plug-in charging. Especially in big cities. That’s one reason electric cars are a bit of a luxury item right now.
- qurren 1mo ago
  Charging is easy in dense cities. The problem is more that property managers are reluctant to get with the beat. Some legal intervention might be needed (e.g. make it a legal requirement to have at least 1/3 the amount of chargers as residents, in preparation for an electric car future) and let the unwilling property managers shut down.
michaelt 1mo ago
This is clearly not a winning idea if you're a spreadsheet-loving engineer that can run the numbers, and is interested enough in clean tech to do so. But that's 5% of the population, tops. To the 95% of people without the inclination or knowledge to check the figures, this looks great! It's a car with zero fuel costs, it's EV charging for people who don't have off-street parking, it's a fix for EVs sitting in workplace car parks at times of peak solar output, and it's most of the benefits of covering car parks in solar panels.

This is like building a gas powered car with a refinery attached to the roof. Batteries exist. Solar panels add weight and design constraints. Why is this a thing? What am I missing?

TeaVMFan 1mo ago

Solar panel efficiency has increased and they have made an extremely slippery vehicle. 4kWh/day and 10 miles per kWh gives 40 miles per day of driving range, enough for many people without ever plugging in.

dymk 1mo ago
Solar panel efficiency hasn’t gone up that much. It’s not like solar panel cars were just barely not worth it - the economics weren’t close to making sense. 10 miles/kWh is also insanely efficient, unbelievably so (well over 2x your average EV), and I don’t see where they back that claim up.
qurren 1mo ago
> 4kWh/day That's over-optimistic and you will probably only get that in a small handful of places in the world like the southwestern US or the Middle East and even then only for part of the year. The hot, sunny, never-cloudy parts of the world also tend to be the ones where driving long distances is most necessary.
- vlovich123 1mo ago
  From some parts of SF to SJ is about 42 miles. Thats a very long distance that you’re likely to get completely on solar. For that long of a commute you probably need a bigger battery but you could easily have most of your costs met for free with minimal top ups. And that’s a very long daily commute. Also temperature doesn’t matter too much. You just need sun. I bet it’s enough for most of California year round with minor exceptions that you need to use infrastructure charging.
  - qurren 1mo ago
    > some parts of SF to SJ is about 42 miles. That's pendantic. Add traffic, air conditioning, a shitton of traffic lights, a restroom stop, and a detour to buy groceries on the way. Oh and if your tires are at 38 instead of 42 psi you're going to lose some range there too. And then some wind, elevation changes. Roof rack bars, because people actually do go on outdoor trips (who would have thought?) And you probably want to arrive with 10-20% left, not 0. You're quickly looking at needing 84 miles of effective range to make the 42 miles safely. 168 miles for the round trip. Yeah, shit adds up fast. My EV has a 363 mile "EPA rating" (whoever those charlatans are) but the realistic range I got from day 0 with a fresh battery in real life conditions is closer to 200-250 miles.
    - vlovich123 1mo ago
      You’re thinking of this as a primary driving vehicle. I’m thinking of it purely as a secondary commuter vehicle / renting when you need to do a longer trip. And you’ve wildly intentionally inflated your estimates precisely to make it seem insane. There’s no roof rack on this (again - commuter vehicle, not a long distance camping vehicle). Also, this is intentionally a super tight distance and very few people are actually commuting from SFO to SJC. I’m intentionally highlighting how workable 42 miles is for a daily commute. Also you should avoid keeping your roof rack on your vehicle if you don’t need it unless you’re constantly using it. They’re generally quick to take off and put on The average daily commute in the US is 10-16miles.

softwaredoug 1mo ago

You’re missing that many people do not live in single-family homes with easy plug-in charging. Especially in big cities. That’s one reason electric cars are a bit of a luxury item right now.

qurren 1mo ago
Charging is easy in dense cities. The problem is more that property managers are reluctant to get with the beat. Some legal intervention might be needed (e.g. make it a legal requirement to have at least 1/3 the amount of chargers as residents, in preparation for an electric car future) and let the unwilling property managers shut down.

michaelt 1mo ago

This is clearly not a winning idea if you're a spreadsheet-loving engineer that can run the numbers, and is interested enough in clean tech to do so. But that's 5% of the population, tops. To the 95% of people without the inclination or knowledge to check the figures, this looks great! It's a car with zero fuel costs, it's EV charging for people who don't have off-street parking, it's a fix for EVs sitting in workplace car parks at times of peak solar output, and it's most of the benefits of covering car parks in solar panels.