Integrate solar panels into EV bodies for supplemental charging

Generally the idea is currently rejected, because the distance gained is perceived as minimal. I found myself strongly disagreeing with this. 1. EVs come with a very large battery by design, allowing panels to be utilized more effectively than in the average home installation, some of which still dont include batteries, especially in the high double digit kWh range 2. Cars are the closest thing to something most people own, that can be built entirely on production lines, has some usable surface area to it and is mostly outdoors 3. For many people cars are being kept indoor most of the time (both at home and at work), but for most this is a situation during which other charging options should be available or they could adapt by simply letting their car stay outdoor more often 4. Solar panels would be able to compensate for passive power consumption 5. When fully charged, e.g. AC (probably not heating due to reduced solar radiation in winter) could be kept running without being concerned about power draw 6. During emergency situations (like getting stranded in the middle of nowhere), solar power would provide a minimum distance that could be traveled every day and power to emergency communication 7. Modularized, possibly even standardized, small-ish panels in various shapes open potential to swapping panels e.g. with individualized designs between cars and even brands or repairing damage by simple localized replacements 8. Even minor gains in distance would reduce lines at charging stations a lot 9. The potential gains aren't that minor at all Panel manufacturers have begun pushing past 25% efficiency, even larger established brand are in the 23% region at this point. Considering degradation, irregular car washes and maybe things like colors being made part of the design, I'm going to assume a flat efficiency of 20%. Solar panels could be placed (almost) all around the car, especially at high latitudes horizontal diffuse radiation can account for as much as 60% of the total irradiation, making even panels orientated opposite to the sun surprisingly efficient (rarely less than 20%, sometimes up to 50% of optimally angled ones possible). Panels could also be integrated to some degree into the glass (or, as done on some watches, at the rim of a glass redirecting some of the light) and even the interior depending on the design. While smaller cars have less surface area, larger ones have a slightly higher power consumption. Just the usable (-ish) top surface area of a Model 3 is about 6sqm, its sides add another about 10sqm. I found no good way to calculate an optimally angled classical array from this for comparison, so I'm just going to assume a conservative 8sqm equivalent (comparing results from various array orientations in online calculators suggest a 9sqm to 10sqm equivalent). Driving normally, modern EVs can achieve about 7km per kWh, with conservative driving this can exceed 8km per kWh. Since in a situation, in which mileage mattered, people would drive more conservatively, but there would be some minor losses over using the battery directly, I'm going to assume 7.5km per kWh. Looking at solar irradiation (e.g. [Global Solar Atlas](https://globalsolaratlas.info/map)), the vast majority of the world has a global irradiation of 3kWh per sqm per day available to them (so that"s what I am going to assume). While November to Februar are quite challenging, from March to October, the available irradiation is usually at least 50% of the yearly average. For the table below I'm deriving the average daily irradiation factor (ADIF) from this [graph by the German DWD](https://solarwissen.selfmade-energy.com/wp-content/uploads/2022/06/globalstrahlungsverlauf_de.jpg), so this data is only valid for this specific latitude (Mid-upper Europe, Canada, very southern tip of Argentina, Chile or New Zealand). Further up north (there is basically nothing further south), these changes would be more extreme, for the US it'd be much more favorable. The average person in the US drives about 50km per day ([US driving survey](http://aaafoundation.org/american-driving-survey-2024)), the average German 19km, ranking high in Europe ([Eurostat mobility survey](http://ec.europa.eu/eurostat/statistics-explained/index.php?title=Passenger_mobility_statistics)). |Month|ADIF|KM per day gained|% US daily trip|% German daily trip| |:-|:-|:-|:-|:-| |Jan|0.25|8.9|17.9|47| |Feb|0.49|17.6|35.2|92.7| |Mar|0.86|31.1|62.1|163.4| |April|1.38|49.7|99.5|261.8| |May|1.68|60.6|121.1|318.7| |Jun|1.87|67.4|134.8|354.7| |Jul|1.79|64.4|128.9|339.1| |Aug|1.52|54.7|109.5|288.1| |Sep|1.05|37.7|75.4|198.4| |Oct|0.6|21.7|43.5|114.4| |Nov|0.28|10|20.1|52.8| |Dec|0.19|7|14|36.8| Sadly I forgot about temperature when writing this, but I got no more time to make major corrections without either compromising on the sub's rules or sleep, but I guess you'd loose 40% to 60% of distance on cold winter days and 10% to 30% on very hot summer days. Edit: I noticed that the link to the solar map wasn't highlighted, so I fixed that.