I used two of the garden solar lights in series to power the LM 386 audio amp.
It will work with the 2 fully charged cells, although only with the volume about 25%.
It will run about 2.5 hrs with the 2 cells before it starves for power.
I plan to add more so the low end research is moot. However it will run limited vol with 2 cells
There are several configurations of the garden solar units.
One I used has the day cutoff sensor, and a cheaper unit (.50 cents on closeout) that's always on.
I ripped out the guts to that one (never did work..
It will charge the cell anyway, but a diode should be installed to keep from reverse discharge at night
I plan to take this further as the lights in wife's garden "go bad " or I find them on closeout such as after a holiday. A bunch of them charging a bank of cells? Or a a little wire from the bushes through the window that
is off the grid. Maybe someone will run with this. I certaintly feel better now about the zero carbon footprint
From the crystal Radios.