Question about Onan Generator

wopachop wrote:
I was cycling my onan5500 a couple days ago. Store my batteries in the garage.

Pulled out battery to start the genny. Ran for about 55mins. Genny still running I disconnected the negative cable and it died instantly.

Also had my 12v disconnect switch turned off.

Made me wonder the dealio. If the disconnect switch was turned on, would the converter then power the fuel pump?

Will have to test that next month. The fuel bowl was filled with gas so I guess it wasnt a fuel pump issue but instead a "making spark" issue?

As it died instantly, it's most likely the control board for the generator shutting it down (by killing the spark). That would be a sensible thing to happen, either specifically by design or just because it's no longer powered so ceases to operate.

The 12V system powers the fuel pump, etc. on the generator. If the battery disconnect switch is in the "use" state, and if your converter is on the house side of the switch, then it would need to be on for the generator to (indirectly) charge the battery and not have it run down from the generator's 12V consumption. If the converter is on the battery side of the disconnect switch, then of course the state of the switch doesn't matter. I guess you could say that the converter would power the generator's 12V needs, but it's just part of the 12V system and providing power into that system as a whole.

In general, there's little reason to ever have the disconnect switch disconnected that I can work out; the main one is perhaps when doing maintenance on the wiring or batteries.

(The generator's 12V connection doesn't go through the disconnect switch because it requires a lot of current to crank it; somewhere in the vicinity of 80-120A on my motorhome, if my little digital panel ammeter is to be believed.)