I LOVE this.
https://drprepare.com/powermax-12v-100ah-lifepo4-battery-and-hub/
I charge it via Anderson Plug-to-12v Cig and plug it into my 4runner cig port in the back, while I am driving. Then 100 watt flexible solar panel when camped. Even without solar I can easily get 3-4 days without...