Generators used in high altitudes

They will run, but with slightly less power.
We do camp at 5000' and did not notice performance loss.
Than when I took my boat to Lake Tahoe at 7000' I had to replace the propeller with one having lower pitch, or the engine would not push the boat in hydroplaning.
Inverter generators do have extra engine power to speed up when needed, so I don't think you are going to have any problems unless you go higher than 10k

You can expect a Champion generator, or any other economy priced gas powered generator to operate under similar principles as a naturally aspirated piston airplane engine. The standard lapse rate applies which says that for every 1000 feet above sea level you are, expect to lose about 3.5% of your rated power. Additionally, for about every 10 degrees F above standard temperature at the elevation that you are (59 degrees F is standard temperature @ sea level) expect to lose approximately another 2% rated power. These are rules of thumb, not absolute statements. They are designed to be conservative so that pilots don't kill themselves, their passengers, and/or innocent bystanders when taking off at higher elevation airports at higher than standard temperatures.

For example: If you are camped at 7000 feet elevation and 78 degrees F outside, expect to lose:

3.5% x 7 = 24.5% rated performance because of the higher elevation

additionally: because it is 78 degrees F outside you can expect to lose another:

2% x 4 = 8% more performance because of the higher than normal standard temperature

Expect a total of 24.5% + 8% = 32.5% loss in power. (approximately)

According to the standard lapse rate it should be 38 degrees F at 7000 feet (you lose 3 degrees F per 1000 feet rise in elevation above sea level)

Some more expensive generators are intentionally over powered to minimize generator losses at higher elevations. They are overpowered (but throttled back) at sea level so they retain a higher % of their rated performance as elevations increase. Generally, you get what you pay for!

Chum lee

You might be able to buy high altitude jets for your generator, depending on brand, which will help. Onans are nice, because they have a dial that can be turned to adjust the air/fuel ratio to compensate for less oxygen at higher elevations.

Conversely they run great at the Salton Sea!

I saw several reviews of the Champion generators now on sale at Costco, commenting that the 2.8KW generator ran a 13,500 BTU air conditioner just fine at lower elevations, but struggled at 5000 feet or higher.

So you need something bigger than 2.8KW.

I wanted a 3100i badly when I replaced our generator but the inverter generators in that size won't cut it at 10,000 ft in the Colorado Rockies. We still have to use a 3500/4000 Champion and even then the converter has to be off to run the roof A/C.

Hi,

The start up surge is the problem. If you get a hybrid inverter charger, you may be able to run the roof air with a 2000 watt generator. The hybrid does "load support" so the generator just needs to provide run time power--not start up surge.

We have two Honda 2000 that are connected in parallel. We routinely boondock at 10,000 plus feet. It takes both of them to run the microwave and coffee maker in the mornings. I ordered them with the high altitude jets knowing they rarely get used below 7000 feet.

Jetting just trims the fuel to match the lower volume of available air at higher altitude. It will not gain you any power unless it is running so rich it will not run well. In that case, jetting will only get you to the point that Chum Lee mentions above.

Actually a engine running properly at any altitude will produce better than a engine running rich.