Converter trips receptacle gfci help needed...

Tried 3 different circuits. All non gfi breakers, all gfi receptacles, all would trip.
Flick the converter off...all stayed fine.

Fear non gfi plug in, afraid I could charge the metal in my rig if there is a short I'm not savvy enough to find.

Already planning on plugging in two battery tenders in for each battery separately.

Looking into having a 30 amp rv receptacle installed to fix it correctly.