> You add a lot of complexity for marginal gains. Peak time you get maybe 500W which doesn't go very far.
The complexity should not be overlooked. The PV panels add a lot of things that can fail: An additional layer that must be adhered or fastened the roof. Transparent panel covers that can become damaged in ways that aren’t as easy to repair as a rock chip in paint. Extra wiring that runs into the vehicle. A charging regulator. Systems to monitor that it’s all working and give the appropriate diagnostic codes if it fails.
Having worked on a lot of older and newer cars when I was younger, I’ve come to appreciate a degree of simplicity in vehicles. Modern electronics and vehicle systems are more reliable, but when the number of motors, sensors, and functions in a car goes up by 10X with all of the new features, a lot of little things start to fail in annoying ways as cars age out.
With solar I imagine old car owners would just ignore the system when it stopped working, but you’re still hauling all of that extra weight around for the lifetime of the car. That extra weight subtracts from your efficiency.
The simplicity of EVs is one of their big strengths! Compare all the cooling, transmission, lubrication and fuel systems of an ICE car to the simple Electric Motor of an EV. Vastly simpler. As an end user, I see it to, my EV has no scheduled maintenance, whereas the ICE wants me to take it to the dealer every 20k miles.
Mechanically simple, yes. Electronically simple, no.
To be fair, modern PV cells are purely solid state (no moving parts, no lubricants or coolants), so a solar system shouldn't add a scheduled maintenance burden, just add to potential unscheduled maintenance costs in worst case scenarios.