Access to Buzz Battery

[EmAre]

I am camperizing my Buzz and would like to run a microwave induction cooktop or kettle. Either I would like to run a 2000 watt inverter directly from the Buzz battery or instal an additional 300AH LiPo battery with inverter. This option would require access to the buzz battery charging system. Has anyone any experience with this sort of setup? thanks for any help, Mike