I got several solar panels new from the company linked below. I also purchased a few used ones at Ham Radio flea markets. I would recommend something in the range of 20 to 50 watts for the panel.This should be sufficient to keep a small handheld radio or a mobile radio running with the right sized battery pack and solar plane size. https://www.renogy.com/solar-panels/rigid-solar-panels/ I also have several of the MPPT charge controllers from this company. I have several of the GV-5 models. One for a lead acid type when there is nothing else available and several for LFP battery packs. https://sunforgellc.com/gv-4/ https://sunforgellc.com/gv-5/ https://sunforgellc.com/gv-10/ I wouldn't recommend the use of any kind of lead acid battery unless you want the cheapest portable battery solution. I've wrecked enough gel-cell and AGM types. They have to be kept on a trickle charger when left sitting around for more than a few weeks. If you don't the batteries self discharge quickly and the plates will sulfate. Once the plates are sulfated the battery is finished. I recommend going with a LFP, Lithium Iron Phosphate (LiFePO4), batteries. They hold a charge for months, some even for a year or more, and don 't get ruined if they sit around only partially charged. The only caveat is the cost . I got a couple of the battery packs from the company at the link below. One was the 6 amp hour BLF-12045W and the 40 amp hour BLF-1240A. Don't forget to get the wall changers for these batteries. The above charge controllers I got were the models designed for LFP batteries, NOT lead acid or LiPO's. https://www.bioennopower.com/collections/12v-series-lifepo4-batteries I also have a 12 volt to 120 volt AC pure sine wave inverter for the rare case where I need 120 volts. I picked up a 300 watt unit which I have set up to work with the 40 amp hour battery. https://gpelectric.com/products/300-watt-pure-sine-wave-inverter/ Now a few words of caution about connecting solar panels to batteries. A few people skip the charge controller and wire the solar panel direct to the battery, through a blocking diode. While that will work in an emergency with lead acid types DON'T try this with LFP battery packs! Just about every LFP battery pack contains a battery protection module. The module will disconnect the internal battery cells from the external terminals in the case of a short circuit, over discharge resulting in a dangerous low voltage or when the battery pack reaches max cell voltage on charge. The last one is the killer. A so-called 12 volt panel is really 20 to 23 volts when open circuited. So when the battery reaches the max safe voltage the protection module will disconnect the internal battery pack so it effectively open circuits the solar panel, which promptly jumps way up in voltage. Most mobile equipment can't handle anything higher than 15 to 16 volts without damage.