RVQ6000 generator throwing code 11

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For two years I have been battling a code 11 on my generator whenever I try and start either one of the air conditioners. Code 11 is an overcurrent fault. The Corrective Action is as follows:

1. Turn off the genset line circuit breaker. If the genset no longer shuts down, the genset is probably okay—check for and repair a short circuit in the vehicle appliances, wiring or shorted battery charger
transformer.
2. Check whether the vehicle engine and genset share the same starting battery. If so, and this fault occurs when cranking the vehicle engine, low battery voltage may be causing this shutdown. In-crease battery capacity or install a separate battery and battery charging system for the genset.

I was able to run both A/C units off the genny for 4 years. Never a problem. Then, all of a sudden, I cant. It does not matter which A/C I try and run. The genny just dies. I can run the microwave, the 105 amp charger, a hair dryer. No problem. Onan has tested the genny under load. The genny can handle 10,000 watts for 60 seconds. So, no issues handling load. I have had the problem looked at six times by different repair facilities and spent more than $1,500 in repair bills. Twice by Onan Cummins directly. Still, no resolution. I don't have time to document here everything that has been tried. But, I want to run the most recent info here and maybe someone can help make sense of it. If I believe Onan, they report IT IS NOT THE GENNY. It is something else.

My latest thought has something to do with suggestion #2 above. The genny has a 25' power wire (2 gauge) coming from the battery bank. When Onan disconnected my battery supply wire and ran my generator off their own separate battery bank, the error code went away. No code 11. So, I traced the wire all the way from genny to battery. The only issue is the wire was squished when Tiffin installed the fuel tank. It has been that way since new. There is no other issues with the cable. My batteries are four 6v golf cart batteries. They test fine. They are less than one year old. They were changed because one of the shops said my problem was bad batteries. That did not fix anything. I have moved and cleaned the ground wire at the genny. No difference.

So, now I am down to the 25' wire running from the batteries to the genny. I am going to replace it with 1/0 cable. My question is does this make sense to anyone???? We have put an amp clamp on the power line when firing up the A/C's. 11 amps at start up, 7 amps while running. The microwave pulls about the same. Why does it fail on just the A/C's firing up. Why not anything else? I don't believe that whatever is wrong is wrong in BOTH A/C's. Even though I have had both A/C's looked at and verified their power draw. And they both have new hard start capacitor and relay installed (another suggestion by a shop!).

Thoughts?