I have several battery packs, various types, sat in a box here. I had not touched them for neatly 2 years. You know the sort of thing - battery with USB, so can be used to power/charge a phone, etc. Generally useful things. I had cause to use one, because something else (an endoscope) which had been in a box for 6 months, had a flat battery.
Obviously these various battery packs were now all flat. One of the reasons for a battery back is for when you suddenly find you need portable power for something like this.
All flat, except one!
I can only assume it was getting enough light from my office lights, even in a clear plastic box, to actually stay charged. It seems happy to charge from my office lights (LED panels). This is crazy!
It looks like Amazon still sell some like this, Blavor brand. They seem to have improved a bit.
The fact it was there for me, when I needed it, is worthy of a recommendation, I think.
But just think, right now, sunshine is charging a Tesla battery, that is powering the house, including my LED lighting panels, that are charging this.
P.S. Holy crap, I only just realised it does inductive charging as well, wow.