Edit: Never mind, “hybrid station wagon”.

Even then, he said hybrid.

You can play around with assumptions, like what if it was driven in stop-and-go traffic at very low speeds? Then your quoted 270Wh figure might be lower.

But anyways, with these general conditions, with the numbers you quoted, and with a 10 kwh battery (aspull), you'd be looking at a net loss of 775Wh/day, which means you could go 13 days between charges.

The point I tried to make, is that solar panels on hybrids/EVs add a lot of practical value to people who can't charge at home/work, and it's not just meaningless greenwashing.

Also that 2.6kWh figure is a yearly average probably, sunlight varies greatly over the year.

Only thing holding off my EV purchase is that I want proper V2G support. If I'm paying for 100kWh of lithium battery capacity I damn well want to use it as a backup for my house.

I have solar panels at home and can charge a car .. but I'm mostly parked elsewhere when the sun is shining the most.

Like everyone else has said - there just isn't enough area on the top surfaces of a car to do any noticeable charging.

(61kWh/month) / (270Wh/mile) / (31day/month) = 7.3mile/day =~ 11.7km/day

(39kWh/month) / (270Wh/mile) / (31day/month) = 4.7mile/day =~ 7.5km/day

My conmute is like 3 or 7 miles (4 or 11 km), depending on where I have to go.

Anyway, I expect that a rooftop installation is much more efficient.

The math does not really work out to a viable product with this bus, but it is not too far off. A city bus that has been purpose-built for low speed in urban areas without other traffic may work as it can make some sacrifices. For instance, since it runs much slower on average it would need smaller engines. It could also use more light-weight material since it won't need to handle high speed collisions. If it is just used for short distances within a city center it could also do away with seats. Lower speed should also lead to lower consumption.

The Solaris Urbino 18 weighs 17.5 tons curb weight. Assuming fuel consumption is pretty linearly related with weight and you could get it down to less than half, you could get a bus with a range of 10 miles per hour of charging. If it drove for 6 hours a day, but got charged for 12, 20 miles on average per hour is possible.

I think it can help calibrate people's intuitions about what you can expect out a pure-solar car.

You also need to remember that inside those shells is basically nothing but a driver. No AC, no batteries, no seats for people beyond the bare minimum. And that's broad daylight. So you need to look at them doing 20-30mph and bear in mind that it's still not comparable to a street-legal sedan of a similar size doing 20-30mph... those cars are essentially as close to "a mobile cardboard box" as the competitors can make them.

You might be able to build something that people would agree is "a bus" that moves with a couple of people on board, but it probably will stop moving once it enters shadow. Anything that we'd call "a bus" is going to need a lot more physical material per unit solar input than those cars have. I'm not sure that even "moves with a couple of people on board" will necessarily end up being faster than those couple of people walking, either. It's effectively impossible to power a vehicle with its own solar footprint in real time. It also ends up difficult to use them to power batteries because having to move the additional mass of the batteries eats up the advantages of being able to gather power for larger periods of time. It's possible, because of course you can hook a car up to solar panels and eventually charge it, but you don't get very many miles-per-day out of it for what fits on the car itself alone if you work the math.

Then you can reduce rolling resistance by using steel tracks and steel wheels ...

... and oh, you have invented the tram/light rail ;)

(But even with solar you need to finance the construction and maintenance, even the slow vehicle need some ... thus either tax finance or charge fares or mix income)

The newest (2023+) Prius brought back the solar roof as an option - and this time it charges the battery (albeit marginally / but not bad for those that drive minimally).

If solar tech gets more efficient or cheaper, I think it starts becoming a much more attractive option in some areas. If you get into the 10+ miles per day range, that would cover a lot of peoples commutes in certain areas.

Can't remember how long it took, think a couple weeks at least?

Those are a very small share of car owners, and EVs are nowhere close to the market penetration to care abut them. But it will eventually make sense.

- The panel sits at open-circuit voltage of 48V

- That then needs to be converted/boosted to 400V (conversion loss)

- The converter needs to talk to the BMS to make sure batteries can be charged at this moment (component that is live all the time and is a current draw)

- Need to think about it, but you want another set of contactors between panel and HV-Bus where the battery sits (current draw)

1km of driving is 150Wh so 1kWh gets you 6.6km or 4.1 mi

Let's be generous and say you have a 500W panel(punchy) for 8 hours at full blast (doesn't happen), you get 500W x 8 hrs = 4kWh. Lets say isolated converter loses you 10% so you are at 3.6kWh Thats 24km or 15mi of driving in perfect conditions.

2x Gigavac contactors, keep them closed costs you 24W, so that lowers the input further to 476W * 8hrs = 3.8kWh, less 10% = 3.42kWh ...

Someone who studied EE might be able to make this more accurate. Back of the napkin math, not totally impossible, but not worth adding it for a trickle charge. Adding components that can break, adding weight etc.

There are interesting solar cars out there where you reduce the weight heavily and fold out big solar sails. Then you are getting somewhere, for a city car you don't have enough surface. For an SUV or American Style Flatbed truck you have so much weight it's not worth it either.

RV panels make sense for the boondocking use case, where you want to charge computers or satellite internet terminal or something, but I can't imagine actually trying to drive on that power.

So you’ll be charging at 2~5mi/h, if the sun is shining straight overhead.

It’ll count for something if you park the RV in the sun for a week as you camp somewhere, but on the road it gives you some limping ability and that’s about it. The main benefit is not running the AC off of the engine.

They are nice gimmicks like that newer model of Prius but far from being economic reality.

Something to keep in mind: A full EV doesn't require oil changes, which you still need to do with a plugin hybrid.

If you're able to do all your daily driving on battery only, then why bother with a gas engine that you aren't using? High speed charging works very well for the occasional road trip; it's at the point where if you take your bathroom breaks at high-speed chargers, you don't even need to "think" about charging.