I’m getting a little tired of misleading semantics when it comes to self-powered flashlights & radios. So here’s the scoop…
When a flashlight or radio says that it is powered by solar or hand crank and there are no batteries to worry about, they are mincing words. Truth is, the power from either charging system is stored somewhere, and that somewhere is a rechargeable battery pack. It’s on-board. Inside the casing. Usually where you can’t see or touch it. So, when they say that the flashlight or radio doesn’t need batteries, what they really mean is that you don’t have to put actual batteries into the device.
Well, that’s good right?
Yes it is.
But, realize that the device DOES have a battery on-board. If you stick to a name brand like Freeplay, Kaito, or Eton/Grundig, it will operate properly for years. All bets are off if you go with a cheap, generic brand.
Can this internal battery be replaced?
Yes. Even if you have to take the flashlight or radio apart, the battery is usually easy to replace. Or have someone who knows how to splice wires replace it for you. Kaito’s newest radios, like the KA600 & KA500 have the rechargeable battery pack accessible through the main battery compartment and connected just like a cordless phone battery, so they are very easy to replace.
Is there such thing as a device that doesn’t use batteries of any kind?
Not in radios due to the power draw, but AIT makes a line of flashlights powered by a super-capacitor instead of a battery. These are the only devices that can be said to be “free of batteries”. If you’ve ever seen a proper magnetic shake flashlight, then you’re familiar with at least one model.

Pros of a capacitor-based flashlight…
+ No finite lifetime
+ Reliability
+ Small & lightweight
Cons…
– shorter run time
– doesn’t hold a charge for more than a couple of hours

So, when you decide to purchase a self-powered flashlight or radio, remember that what you are getting is a low-maintenance device that will be ready when you need it. But, you are advised to take care of the internal battery pack, and do what you can to keep it in a charged state.