Solar for starters

I think we've all needed a jumpstart for our cars every now and then. We leave the lights on or something and a few hours later, we're hearing that familiar "click-click-click" and scratching our heads.

So why can't cars come with a solar powered battery that stores enough of a charge to "jumpstart" your car without another vehicle present? They make those portable battery packs that can jumpstart a car, why can't they put one in the car and power it with some solar panels on the roof?

That's the idea.

I guess this might make tow trucks less busy....but I'm sure they're busy enough as it is.