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Get a dc-dc converter board and hook it up as an alternative for devices that need a lot of power. A beefy capacitor before the dc-dc converter, from the solar panel can ease the stress the solar panel places on the converter or device being charged, too. This lets you adjust the voltage coming out of the panel to some degree, it's actually what is in your USB charging panels already but set for 5V.
I use this and personally like that it is adjustable and cheap, also really small