I’m interested in a solar charging system that would be used as a backup power source. The speed with which it takes to charge is not really a big deal, the bare minimum would be enough. I would prefer to have a system that charges slow, takes up less space with regards to the Solar Panels and offers enough capacity to run a large appliance such as an air conditioner for example for several hours.
I haven’t had much luck finding a commercially available solution that meets these requiremetns, so I’m guessing I may have to go the DYI route.

Can anyone offer some advice/guidance on how to proceed? Also, one other question. If given enough time, would pretty much any size panel eventually charge a battery?
Update: Thanks for the information. However, the commercial unit in that link is what I’ve normally seen online. That unit boasts a fast charging system, and I’m guessing that adds to the price. Since fast charging is not a priority for my scenario, that one is not a good fit. I may look into that DYI guide, although I’m still not clear on my second question which was regarding the size of the Solar Panels. For example, if there was a such thing as a panel that took 30 days to charge the battery because of its small size, I would be perfectly happy with that since I don’t plan on having to use the system on a regular basis.