I think that everyone comes up with different answers about generators. If you're diesel powered, you have the choice of a costly, noisy, diesel or an LP model that's sucking up your very limited supply of furnace, water heater, sometimes refrigerator, and cooktop fuel. What you really have to look at is what are you going to use the generator for. We tend to put very little hours on our generator, primarily using it to run the microwave and A/C when we stop to eat lunch at a roadside park or rest stop. We hate RV parks that are what I call parking lots with hookups, but we do look for state parks and other wooded facilities with a minimum of water and electricity and preferably sewer hookups. Consequently, if I had a diesel unit, I could probably use an LP generator with no problems at all. How much are you going to use your generator??
Sigh...another dilemma. ;-)
Since we like the idea of dry camping/boondocking I imagine we'll use the generator frequently -- typically in the way Ron does, to keep the batteries charged -- and then run off of the batteries/inverter.
We have a similar setup here at the house -- 12 golf cart batteries and a pair of inverters for a whole-house UPS. If the batteries were to ever get fully discharged, we would run our generator at close to full load (the inverters have an adjustable charge rate) long enough to charge them back up and then turn it off. Fortunately we've never had to run the generator -- the batteries will run our essential loads for about 24 hours.
The loads in a RV are less of course, but there is much less battery capacity as well. Without having actual experience or doing load calculations I'm not sure how often we'd have to recharge the batteries, but I'm guessing that running the generator once or twice a day would be enough. Maybe less without using the furnace fan, or any other significant loads.
If that were the extent of it we could probably get by with the LP genset but I really like the idea of having the potential extended run time of a gas or diesel (dep. on chassis) generator, primarily to run the A/C.
I am concerned about the negatives that you all mentioned though -- additional weight, extra expense, and exhaust fumes.
I suppose noise is an issue with any generator (LP, gas, or diesel) but my understanding is that diesel units may be a bit louder than the others. Any opinions about that? I suppose if they're all obnoxiously loud it's a mute point.
To avoid the noise, I've read that some RV owners carry a small, portable, Honda gas generator. I've heard them run and they are _very_ quiet. They also have the advantage of being able to be set away from the RV. IIRC, they aren't particularly powerful though -- maybe 1-2KW depending on the model. That would be fine for charging the batteries and/or running small loads but I'm wondering about the A/C unit and the microwave. Actually, the microwave might use 700-800 watts and could be run off of the batteries/inverter for a short time if the outlet was wired that way (we do that here at home). So I'm sure even a small Honda generator could handle the microwave, but I don't have a sense of what sort of load the A/C unit represents. An A/C unit might not take too much when running but could be hard to start. Anyone know the minimum size generator required to start the A/C unit?
<Thinking out loud at this point> Of course, it wouldn't be practical to run the A/C unit from a portable generator, even if it could handle the load, because the fuel tank would need to be refilled every few hours. Then there's the issue of carrying enough fuel. One Jerry can might fit on the hitch mounted carrier, but that amount of fuel won't last very long if the generator is running the A/C.
And so we arrive back at square one... ;-)
What do you all think? Is it worth carrying a small Honda generator for routine battery charging and all loads except the A/C unit? Or does the OE on board generator charge the batteries fast enough that the noise generally isn't an issue?
It looks like PC installs a high quality Xantrex pure sine wave inverter in their rigs. I seem to recall seeing ratings of 1,800 to 2,000 watts, does that sound right? If so, that's much better than just about any other class B+/C I've looked at. As I said above, an inverter that size could easily run the microwave and two decent deep cycle batteries could supply enough juice for short periods of time -- but I gather the microwave outlet isn't wired that way?
One final thought -- I know most diesel engines can be idled for hours on end without harm and take about 1/4 of the fuel that a gas engine does while idling. Would it make sense to charge the house batteries that way? That wouldn't solve the A/C issue but would provide extended run time for everything else while conserving the LP and being relatively quiet and fume free.