This may be a stupid question but given that these cars literally absorb light... do they pose a danger on the roads in terms of visibility to other motorists?
The main issue is the extra cost of this worth the 16km (10miles) in range added per day. It produces $1/day in electricity, so it needs to cost less than $2.5k for it to be cheaper than electricity.
This is highly dependent on what you pay in electricity (system produces 33kw/week on average).
Maybe under ideal conditions, at a very high per KWh price (25c or more). The math would only work in a very sunny place with very expensive electricity (Hawaii, perhaps?)
Nevertheless very black materials can be stunningly dark https://en.wikipedia.org/wiki/Vantablack
A quick Google search [1] suggests that a (standard?) solar panel absorbs ~2/3s of the light, so it probably reflects enough to make out the car on the road. But the question actually becomes valid and important once we discover solar panel material that can absorb even more light (think Vantablack-like absorption).
Very good question!
[1]: https://news.rpi.edu/luwakkey/2507, search for "absorbs 67.4 percent" on the page