My Son has been designing off grid home solar systems in 24V and 48V for several years, he also has built 12V systems for camping trailers and food truck systems. When I asked him to help me put something together for my rig, I told him I wanted to run a 12V fridge/freezer unit, some LED lighting, my CPAP machine, and some sort of Fan/swamp cooler style air cooling system in the summer or a diesel heater for the winter. He had me pick up a LiFePO4 200Ah battery and a 200Amp folding panel. He gifted me a Bluetti EB70 Solar generator unit. He said most of the solar generators have more features built into them than I could afford to build into a DIY build. MPPT Controller, 120V, USB outlets, even a wireless phone charger and a built in spotlight all standard for under $500. The extra LiFePO4 bank and panels let me have extra battery reserves and allow me to charge and use the Bluetti Solar Generator at the same time. That thing will even charge in the truck while driving. I have never ran out of power the way I use it. I have ran it to zero to see how much longer it will run over a lead acid/AGM battery. It's supposed to be good for like 10 yrs+ compared to 2-3 yrs for many lead acid batts. It charges right back up while driving, or I can plug it into the solar panels and/or a gas generator during daylight hours. It can charge with more than one source and can be discharged while charging. Just a super cool way to store, use power when camping.
There are several makes and models out now at prices and configurations that make DIY-ing one a more expensive option at component pricing and sourcing. Anyone interested in learning way more about Solar should look up Will Prowse on YouTube. He also has a website called Diy solar and a Forum where one can get design schematics and ask questions and get ideas till your brain hurts!