I wasn’t sure whether the small 0.1 A charging current yesterday afternoon was due entirely to the shade on the PV panel or whether it had something to do with minimum input requirements for my PCM 60x charge controller. On paper, the 265 W solar panel should be able to charge my 500 Wh battery in two hours or less.
I left it all connected while I was at work today, and checked it this evening. The battery voltage has risen from 26.1 V last night up to 28.3 V! That’s quite close to the 28.6 V cutoff that I programmed into the charge controller, which suggests that the solar panel essentially gave me a full charge. How exciting!