Hey Kevin.
We have an EcoFlow Delta 2 which has a 1024Wh capacity, and as Randy mentioned about the similarly powered Yeti 1000 it will run the Dometic for about 3 days without recharging depending on enviromental conditions, and if that is all it's used for, but sometimes a toaster gets plugged into it, and re-chargeable devices etc. which can bring that recharge time down to considerably less duration. I agree, the cigarette plug charger is painfully slow for recharging, which is the result of the limited current capacity of the lighter plug, so up until recently I would charge with solar, or AC if available, or our generator.
EcoFlow recently came out with a 800W DC to DC Alternator Charger for TV's that will charge the sogen in a little over an hour, but seemed somewhat overpriced.
EcoFlow 800W Alternator Charger | 800W Alternator Charger | EcoFlow
Early in Sept. I happened to run across a kind of flash sale they had, and was able to snag one for $199 which was about 1/3 of it's normal price. EcoFlow does that sort of thing quite often with their products, especially when they come out with new products, but that was quite a bit larger discount than I'd seen before, so I decided to grab one.
The downside of EcoFlow (and this may be true of other sogens as well) is that they tend to use proprietary connectors, and also, you run their products though an app you install on your phone that they have developed for their products. The app works well, and gives you a lot of adjustability with their products like charge rates and charge limits along with monitoring the SOC, and real time charge input and discharge output of the sogen, as well as hours of charge remaining at current discharge rate etc..
So it's very nice in that way, but because of the brand specific app, I don't think the 800W Alternator Charger could be used with any other brand sogen without a real tech geek somehow hacking it. I did a temporary installation, with the cord for the charger hooked to the battery and ground then coiled under the hood, and the charger & sogen are hooked to it only when recharging is needed. Then it can easily be removed for installation into another vehicle if desired. The downside of that type of installation is it isn't available while driving like it would be if installed as intended with the cord entering the TV cabin and the charger mounted inside at a place where the sogen can sit. It's still relatively new to me, so I don't have enough experience with it yet to give an informed review, but I'm cautiously optimistic.