I have an Onan quiet diesel 7500 hdkaj that has an issue that has baffled the techs so far. Everything worked great and suddenly the generator has issues. I took the coach in to have a new ex manifold and turbo replaced recently. While the coach was in the shop, they left the house batteries on for a week and had to charge them to run out the rear slide.
When I retrieved the coach, I had no house power and batteries wouldn't charge. Took coach to a new shop and found the chassis ground and other main ground were not connected to batteries. Batteries were dead. Replaced batteries and attached ground cables. Everything works and charging cycle is good.
Now I have a generator issue. After genny runs for a few minutes, it bogs down and AT switch drops out on genny side. This is due to voltage drop and switch is working as designed. Genny runs back up after a few seconds and AT switch kicks back in. This is a constant cycle. Note that nothing is turned on. In fact, I've shut off all breakers except inverter/charger breaker and batteries are charged. When on shore power, everything works perfectly.
Fault code is 38 on genny, which is overcurrent reading. Put voltage meter on genny and read both legs. When all is well, voltage is 119.2. When drop occurs, it's dropping to 70.8. When I shut off the inverter breaker at the main box, genny purrs like a kitten for hours.
So what is causing the voltage drop with nothing on but the inverter? Any ideas?
BTW... Inverter is Xantrex freedom 458 with heart interface remote panel. Called Xantrex and could barely understand the tech advisor, but basically they told me to try different power share settings. Tried every power share setting. No difference. Turned off charging function. No difference.
Took genny to Cummins. They said it was AT switch. I disagreed and argued that the switch was working as designed. However, I shelled out $200 and put in the new switch. No change.
Anybody have any ideas? Thanks in advance.
