There exist totally transparent panels that you can put in your crystals of the car.
There are different types. The cheapest ones filtrate around 65% of heat and the best one made out of graphene filtrates 80% of heat from solar radiation. They are totally transparent.
I think transparent solar protection films are key in this car because you can avoid a lot of heat inside the cabin.
Good luck with your project I follow you from Spain.
Cold climate users report much better range when set to finish charging right before driving, so the battery has been pre-warmed by charging current.
Most of the EV owners where I work leave their EV cars in the garage during the Chicago winters.
On the flip side, COLD weather reduces range even without using any heat at all, because it temporarily reduces the battery capacity & increases air density. Also, resistance heat like in the upcoming Aptera takes about 2-4 times as much power as A/C.
Combining all those factors, one could argue it's better overall to let the sun heat the car more. Any small decrease in hot weather range will be more than compensated by an increase in cold weather range.
I carefully tested my own small-cabin 500e BEV & was surprised that it gets the exact same range when it's 60F out with NO heat or A/C, as it does when it's 95F & I set A/C to 78F with just enough fan to keep me cool.
I then learned 2 things that explain why there's no difference:
1) Other users reported that 500e A/C only takes about 0.25kW*, equivalent to a 1/2mph headwind on the freeway. *after about 1kW for 5 minutes to cool it down
2) Even though high temps are bad for battery LIFESPAN, they improve battery EFFICIENCY, peaking at around 120F.
So in my case, small A/C draw was compensated by higher-temp battery efficiency.
I have read in 3 different websites that air conditioning takes around 10% of range in electric vehicles
@Javier F The energy to cool the similarly-small cabin before driving my 500e in 95F (35C) is only about 0.08kWh. That's about one fiftieth of the daily energy collected by the solar cells, reducing Aptera's daily solar range by only 0.8 miles.
Don't get me wrong, I love efficiency, but with kW AND dollars: A half-size battery is much lighter for a more efficient AND less expensive vehicle that still goes more than 300% of the average US daily drive.
Can you give me more detail on what kind of crystals you are speaking of? Are you talking about photonic crystals?
I don't know why you'd "think transparent solar protection films are key in this car", since unlike most other cars, this one is available with only 1 windshield & 2 door windows transparent (with the solar hatch option).
Although I agree with you as far as choice of solar panels, it needs to be a cost effective replacement. There have been many suggestions on this forum for improved design and additions. I feel strongly that these are all good, but for now, we need to keep the design basic and simple and get a product out on the market at its proposed pricing structure. If it is successful, there will be a more flexible lot of options and pricing structures for those items that people want to invest in.