@pjf@cloudisland.nz
Aha, looks like I need Maximum Power Point Tracking (MPPT) doodad for charging off a solar cell, and I doubt my $10 panel already has one integrated.
If I understand correctly, an MPPT doodad lowers the current draw from the panel to maintain enough voltage to charge; otherwise the battery charger can try to draw too much, which drops the voltage, and one gets nowhere.
A random blog post recommends a CN3791, which are only a few dollars, so I shall continue investigating
@pjf@cloudisland.nz
I've been trying to understand how antennas work, and it's all deep eldritch shit. Make sure your antenna is an exact fraction of the length of the silent whispers you wish to hear from the void. Make sure the antenna has a solid plane to bounce the whispers off, but somehow you can get away with just a couple of wires that suggests where a solid plane would go. Make sure your cable isn't a cursed length, which attracts unwanted attention.
RF engineers are heckin' magicians.