Many of us use Bluetooth headsets, and it seems that the majority of us who do either use it in an always-on-the-phone fashion, or only in the car. Which makes sense to me. But what about a headset designed to never leave your car. Sure, it could be charged from your DC outlet, but chances are that’s only powered when the engine is spinning.
My solution is a clip-on charger. One side is a solar panel, and the other side is a nondescript box, much like a garage door opener. Inside you connect your headset, and flip down your sun visor to expose the solar panel to the sun. This charges the headset while you’re not using it. The box could also contain a small battery, so you can charge that cell during the day, and then have it charge your headset charge from the battery when sunlight isn’t available.
This way you have a somewhat secure place to stow your headset when you’re not using it, and top off its batteries. The built-in battery allows people who park their cars in garages or ramps to store power for when they won’t have sunlight.
The idea could also be used to power a speaker phone system too.