For those who park outdoors, away from a power source, there are solar-powered battery maintainers. These connect to the car battery, and some cars can be charged via the 12-volt power point inside.

But they’re also forgivable. With a smart 12V trickle charger and maintainer, you can revive your car battery in a relatively short amount of time. And this one from GPED is discounted to $20 on ...