I carry med's that require being kept cold. I run an electric cooler off of the box receptacle. I did have a deep cycle battery setup with a power port as a backup when I had to turn off the truck for ferry rides or lunch time stops. I just ordered from Amazon a 1200w portable power station. It provides 992Wh of power with 1200W continuous and 3600W peak output. I wanted to run my 115V, 5a (575W) house freezer with a 17.6 LRA (2235.2 surge watts) as well as the cooler in the back of the truck. Many of the power stations have pass through now so while traveling I'll plug the cooler into the power station and the power station into the 400w inverter of the truck. The 1200w power station max charges at 280w input and the cooler runs at 47w. Sounds great in theory doesn't it? lol