pianotuna wrote:
How many gallons of fuel to idle your v-10 for two hours?
About 1.4 gallons (~0.70 gallons/hour).
Keep in mind it's very rare that we have to do this. This mode is to use the alternator to expose our batteries to 14.XX volts every week or so for a refresher full charge, or alternatively, to charge our batteries whenever we sense that we may be camping (too) close to what we sense might be extremely noise-sensitive folks.
Otherwise we usually charge with the little tiny 650 watt Honda which consumes around 0.51 gallons every 5-6 hours, but only exposes the batteries to ~13.8 volts from our stock built-in converter.
If it's pouring down rain, or if we for some other reason(s) don't want to mess with the Honda portable generator, we charge with the convenient built-in Onan generator ... which consumes maybe up to 0.35 gallons per hour under the light charging load. Just like with the Honda, we use slippery synthetic oil and H.E. spark plugs in the Onan. If we don't use the Honda much or at all on any one particular RV trip, the extra fuel we carry along for it can serve as an emergency supply for the main RV gas tank - since we sometimes drycamp way out when looking for rocks/minerals/fossils.
The Onan generator was installed by Winnebago so as to be well within the U.S. NP standard of around a 66dB noise level at 7 meters and it's steady low humming sound can easily be tolerated inside the RV while talking, book reading, sleeping, etc. ... unlike what the built-in generator situation might be in certain other Class C motorhomes. The Onan generator also has a convenient altitude adjustment knob on it to both keep it running at maximum efficiency at high altitudes, and ... help keep it odor-free at high altitudes by keeping it from running too rich.
All our battery charging is of course enhanced by the batteries being AGM type, which accept more charge faster at all applied charging voltages due to the extremely low internal resistance of AGM batteries.