Question about Onan Generator

drsteve wrote:

Son of Norway wrote:
The battery supplies the energy needed to run the generator, right? So, while the generator is running, does it send a 12-volt DC current back to the battery to keep it charged, or does the generator just continue to drain the battery until the battery no longer has enough voltage to keep it running?

No. The battery supplies the energy needed to start the generator, not to run it. Once the generator is running, there is no drain on the battery.

Built-in RV generators do typically need 12V power when running, not just when starting. If the generator is getting that power from a battery that is not being otherwise recharged, it will be a drain on that battery. Generally things are set up to the converter, powered by the generator, is powering the 12V system including the generator's control electronics and also charging the battery, but without that the generator very definitely will be draining a battery in most RVs. (The 12V power is needed for the generator's fuel pump, control electronics, etc.)

There are of course different designs of generators, and I'm sure there probably are some RV installations that do not require external 12V power once running, as well as some that have a 12V charge circuit built into the generator. To my knowledge, they're distinctly in the minority; most are set up as described above.