Solar Panels.

[wildwood]

Is there is reason why car manufacturers haven't incorporated a solar panel into the roof of new model hybrids and all electric? They could easily be made to shape to the contour of the roof so won't be unsightly.

I would have thought that a couple of sq metres of panel would generate a considerable amount of storable energy, so saving on charging costs and/or petrol. If your car is all electric and runs out away from a charge station you can pick it up the next day and drive at least to the closest place of charging.

[Tilly2]

I would imagine that the battery would need to be quite large, in order to store the solar energy.

[bhg481]

A typical solar panel from Maplin's generates peak 13W from a toughly 1/3 sq meter panel, giving you about 80W from 2 sq meters.
1hp = 746 watts
A small car engine is more than 50hp.
Solar panel is OK for keeping a battery charged to replace power used by alarm etc but no use for powering vehicle itself.

[Buenchico]

Worth a read:
https://content.sierraclub.org/evguide/blog/2014/01/why-solar-panels-roof-electric-car-may-not-be-pie-sky