Maybe you have heard about Sonomotors and its futuristic electric car, the Sion. If not, here is the link to its website: https://sonomotors.com/
Anyway, the manufacturer claims that this car can recharge up to 30km on one day using its own solar-cells.
I have come to Physics Stackexchange, because I want to know: Can this be true ?
(I am looking for well-researched, fact based, answers without any bias for or against this car.)
EDIT: got some good answers... but let's really crack it down... Can we chose Germany for instance, look at the solar radiation per month and compute an expected range per month?