What you are asking defines my SHTF battery bank/ solar generator/ solar panel strategy. Everything I have is all portable and small scale, one because of cost, and two because any disaster will require me to intermittently run my 240v generator to power my well pump. I can also supplement with smaller inverter generators for keeping the fridge/ freezer/ entertainment going while only sipping gas. It's not a great long-term strategy but I live in an AO where it would be difficult to do substance farming without it being my full-time job, so I prep for the most likely situations short to medium term durations.
I can share some links of what I have bought, tested, and stacked back but I picked most of it up on sale, with coupons, and focused on low-cost portability over trying to power my house with it. My goal is to keep small portable batteries charged, so I can charge other small devices should we move past the point of no grid. I read reviews and went with mostly no name brand stuff.
First of all, medium to large size battery banks will give you the most bang for your buck if you can charge what you need to charge with a USB port. As soon as you jump to 120v solar generator the cost jumps, but its battery size doesn't. I have several of both. Depending on how many or what size solar panels you have, having some deep cycle 12V batteries with various adapters and charge control units can expand your capacity should a situation draw out. I have two deep cycle 12v batteries on our camper and a portable solar panel for those as well. I also saved the older still functional 12v battery that was replaced by two new ones.
The first one is the largest battery bank I have. It's a slow charger but has a larger than normal capacity. No 120v conversion to worry about. Do your own brand make model research, these are just examples of what I have. I wouldn't want to vouch for any of these specifically and while I haven't had any issues, no name brand stuff like this is well, what it is. I have two of each of these banks:
70000mAh
https://www.amazon.com/gp/product/B0BRCWS6T2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Next size I have is: 50000mAh
https://www.amazon.com/gp/product/B0BF54MTCG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Other than some much older low capacity banks this would be the smallest I recommend: 26800mAh
https://www.amazon.com/gp/product/B081C5TY2J/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1I have a few cheap low end solar generators as well. They are basically battery banks with a 120v inverter built in. Again, I got most of these on sale, with coupons etc. Look for similar items at better prices. I always check the reviews as well. They can charge and run small things, Laptop, internet router/ Wi-Fi router if the power is out and generator isn't running, and the internet still works
I have two of these:
https://www.amazon.com/gp/product/B0B6H85ZQZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1One of these:
https://www.amazon.com/gp/product/B0CRBJYKLN/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Just ordered this one:
https://www.amazon.com/gp/product/B0BZRZX1ZN/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1The last item is solar panels. Be sure you have correct cables and charging ability to connect to the above:
I keep this one in my camper:
https://www.amazon.com/gp/product/B07VL3XF96/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1https://www.amazon.com/gp/product/B0BWRQT97Z/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1https://www.amazon.com/gp/product/B092XDR3D5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1https://www.amazon.com/gp/product/B0BG71GW9Z/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1https://www.amazon.com/gp/product/B0C2PMS74J/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Over the last couple years, I ended up with a misch match of portable gear that I use for various off grid activities to include camper camping, tent camping, hunting etc. All said and done I could have spent all the above coin on better single units, but all said and done I don't mind the variety and redundance for keeping small batteries charged in a grid down situation. Having a few small portable solar panels tucked away for emergency use that didn't cost much is ok by me. This was all piece meal purchases over 2~4 years based on sales etc. You will notice that several of the links show as not available but give you an idea of size etc.
ETA/ What I posted above is mostly plug and play stuff. You can do it cheaper with just solar, 12V batteries, and adapters, which I also have.
2nd ETA/ Take all the listed ratings of all the above no name stuff with a grain of salt. In most cases you can subtract around 25% of their advertised rating/ numbers.