It is a little technical. There is this effect: Effect of Sun angle on climate—Wikipedia And then there is the additional effect of the solar panel not being aligned with the sun rays in the winter. So, that is more than two cosine factors going into the calculation if you also include atmospheric effects, distance traveled by the rays in the atmosphere, time window for the sun, etc. Here is something everyone can understand: You can go to the beach and stay all day and you won’t get any sunburn in the winter, but in the summer, it takes only ten minutes to get sunburn. That is not a malfunction.
Update- the dealership refuses to investigate it more, just tells me there is no problem. I'll go pick up the car, but will file complaints. Any suggestions who to complain to? As I said, they insisted that the solar charging roof isn't even supposed to add to the EV miles. Even though I explained that it used to do so. I'm sure someone at Toyota told them that? But I suspect there aren't many there familiar with the solar charging roof? So they should have made more calls, to actually find someone familiar with it, rather than giving up on it easily and telling me there is no problem??
That's an apples to oranges comparison - NOT really a comparison. Houses are fixed, immobile. Solar panels are ONLY installed on areas in the roof where they will generate power year around and angled properly to do so in a much larger array than the small roof surface area of your car!!!!
Are there any others reading who have the solar charging roof? Some imply here that it won't work in the winter, even on bright sunny days? One reader is saying his has not been working lately either? Any other solar charging roof owners? Only functions in the summer? Would be good to hear from other solar charging roof owners.
The house-roof solar panels are also aligned for an optimal angle to face the sun more directly in the winter, which helps, increasing the cosine factor. The solar panel on the Prius PHEV is too small to even power its own computer when the sun is weak. Therefore, it won’t work if the sun is weak. It works when you turn on the car because you are getting power from the car’s 12-V system to run the solar-roof computer.
I am pretty sure your car is 100% fine, as I explained. Just wait until late April, and it will work again.
going back to the first few posts, if you are getting 50% of the effectiveness of mid summer, and you were getting 2 miles then, you should be getting at least 1. i wonder what the service manual would have to say about it, or the new car features manual.
No, that is entirely false. As I explained, in the winter, you only get about 10%, if not less, of the solar radiation you get in the summer, and that is not enough to power and turn on the solar-roof computer.
i was going by @ChapmanF 's second post. i respect his knowledge and understanding, but any of us can be wrong at times.
Yes, I understand that. But zero charging at all in the winter, in southern california, even on very bright sunny days? That seems to be what some are saying?
That post of mine was specific to Los Angeles latitude, and also closed like this: If you then do take into account the fewer hours of sunlight, you'll end up with well under half. How much less? I don't see the fewer hours by themselves reducing a 50%+ figure to a 10% figure; winter doesn't drop daylight hours by a factor of five in Los Angeles. Also greater losses in the atmosphere from a longer shallower path? Seasonal differences in cloud-cover patterns? I haven't worked out all the factors that go into the overall reduction of available energy. My point in that earlier post wasn't to try to put a lower bound on the available winter energy, but an upper bound: even if you leave all other considerations out, the cos θ factor all by itself chops what you can get by around 50%. Of course, you could fix that one factor by parking your car tipped up to face the sun.
Much of the discussion here seems to be about seasons, that the solar charging roof won't work in winter? (Which is certainly not mentioned in any of the info about the car, nor the manual, that it is a summer-only feature?) (Again, I sure hope that some others with the feature will chime in if that is true for them?) But that is not the excuse the dealership gave me, I was told it is not supposed to add EV charge at all (nothing about seasons), which certainly is not true, as it worked for me and others before. (And I would certainly not have gone to much extra trouble and expense to get that feature if that were the case?) So quite frustrating. And it is even listed in the manual, as I mentioned somewhere above.
My car parked in the sun all the time, Of course not all days sunny. But again, no charge added at all for months. Not a matter of less, but zero! So I'm not sure about this seasonal explanation causing no charging at all?
Comparing the Prius PHEV solar roof to a house solar roof is apples vs. oranges. House solar roofs are placed at an angle and direction toward the sky to optimize the energy input year-round, whether it is summer or winter. You lose some in the summer but gain in the winter from this angle setup. The Prius PHEV solar roof, on the other hand, is always horizontal, which puts it at a great disadvantage in the winter. There is also a threshold at which the solar roof will turn on, which is the threshold to power on the solar-roof computer. It won’t work as a result in the winter, as the solar roof won’t provide enough power for the solar-roof computer. In the winter, it works only when you power on the car, as the solar-roof computer can be powered by the car’s 12-V system during insufficient sunlight.
