How about solar charger

A solar charger is a charger that employs solar energy to supply electricity to devices or batteries. They are generally portable. Solar chargers can charge lead acid or Ni-Cd battery banks up to 48 V and hundreds of ampere hours (up to 4000 Ah) capacity. Such type of solar charger setups generally use an intelligent charge controller.

These portable gadgets marry solar panels with battery packs—they're small and lightweight enough to not add much heft to your pack and powerful enough to juice up your phone, headlamp, and other small tech. Many solar chargers come with ports to plug your devices in directly, while others fill up separate power banks you can store in your pack.

Learn More › Solar chargers can translate the sun's energy directly into power for small electronics. Whereas larger solar panels require a power station to play intermediary (lest you burn up your electronics), these smaller panels have just the right amount of kick for the likes of a smartphone or satellite messenger.

I called in 13 different solar chargers from nine different manufacturers for testing. The main criteria was that it be a portable panel that you can use to charge a small electronic device, like a smartphone or a tablet, without the need for a power bank as an intermediary.

Many solar-powered devices can reliably charge more than one device at the same time. This is important if you'll be sharing power among a group of people or have lots of tech to keep powered. Some solar chargers only have one power output, so they can't charge multiple devices at once.

Great portable solar chargers prioritize size, weight, and packability over all else. These smaller models are designed to charge electronic devices with lower energy needs, like cell phones and smartwatches. But if you're trying to charge something that takes a lot of power, they won't work as well.