Charging fault when trying to trickle charge EV of off AC300

I know this isn’t the most practical use case, but I liked the idea that in a severe emergency situation I could theoretically slow charge our ev over the course of a few days via our portable solar panels and an AC300. Just tried plugging the EV charger in and I get an error fault on the charger unless the AC300 is in UPS mode. Am I missing something or is this just not possible? Is this an issue unique to Bluetti or a limitation of portable battery systems?

Hi @filmgeek47 ,
Our machine is float ground, so when the machine charges the car, the car will prompt the connected energy storage device to open ground. This requires you to purchase another Neutral-Ground Bonding plug.
Plug the Neutral-Ground Bonding plug into the AC outlet.Turn on the Power of the AC300+B300 , and turn on the AC output to charge the Tesla/RV/camper van.