It's the lack of value that turns me off.
Say a person goes camping for a period. He has -almost- enough battery to last the period without recharging.
Then, buy only a solar panel. A panel, wire and clips. Nothing else. No controller. Connect the panel direct and enjoy what extra ampere hours this setup will generate during the camping period. Sixteen amp hours per day will upgrade primitive living to relative comfort. Any time I must use a flashlight for an evening visit I damn sure better hear a whinny from a hobbled animal close at hand.