I was about to start a thread on this topic. I'm getting ready to buy a Honda EU2000i and EU2000i Companion (both floating-neutral), with the Honda parallel RV wire kit plus 30 amp adapter plug, and a Bergs dual feed fuel tank.
I also have a Progressive Industries EMS-HW30C, which should error the floating-neutral.
Right now I'm using a Sam's Club Black Max BM903550 Series 3550 watt floating-neutral generator with a "neutral-to-ground" adapter plug inserted into one of its 15amp 120v sockets and my RV 30amp plug inserted into its 30amp 120v socket. The adapter plug keeps the PI from erroring off on floating-neutral with this generator.
I've been reading advise on how the Honda twins may or may not work with the PI, see one of the posts on Mike Sokol's No Shock Zone (Generator Ground-Neutral Bonding | No~Shock~Zone
Do you have pictures of how you are doing your non-Honda parallel wires? I read where that may be important.
Are you inserting the adapter plug into the Honda that's providing juice to the 30amp RV plug going to your PI? I also read where that may be important.
The EU2000i Companion has a 30amp socket. How are you connecting your RV to your pair of regular 2000i without the Companion model as part of the pair? I thought the regular 2000s only had 120v 13.3amp sockets.
I know I have more questions than answers, which is why I was about to start a similar topic thread... -ray