Hinged to each other, each two, open up like a pair of glasses, finally covering the whole car. Switch it "off" and they fold back in to one single folded up thingy.
O - the folded car cover
OO - stage 1, two of the sunscreens open side by side with a hinge and small servo in between
O OOO - stage 2 - each of the circles opened in two
_OOO OOOO _O - stage 3 - again each one opened into two
_OO0 OOOOO OOOO _OOO __O - stage 4 - prpeparing to doulbe its size by opening up...-- pashute, Jun 29 2016 Or do it like this... https://en.wikipedia.org/wiki/Miura_foldFolding carefully... [neutrinos_shadow, Jun 29 2016] You forgot to mention the things should be covered with solar cells, to help recharge the car battery.-- Vernon, Jun 29 2016 One of your hoops on the last diagram has suffered an accident...-- MaxwellBuchanan, Jun 29 2016 I thought this was going to be an adaptation to the "Fake PHEV charging lead" idea.
This is cooler than I thought it would be. (+) Interesting.
Carry on.-- 2 fries shy of a happy meal, Jun 30 2016 Clever! bun [+]-- whatrock, Jun 30 2016 What makes this incompatible with non-electric cars?-- notexactly, Jul 18 2016 not-exactly, sorry-for the-missing hyphen. Its: Electric car- cover of-course.-- pashute, Aug 04 2016 And of course, the hyphen that matters is the one that gets caught by the line break.-- notexactly, Aug 05 2016 random, halfbakery