Twenty months ago this area lost power for 4 days. A neighbor brought in an extension cord from his generator. A gas engine burns a lot of fuel even with no load. He kept it off much of the time. Even then, he and tens of thousands of others spent hours each day searching for an open gas station.
Years ago I quit using uninterruptible power supplies. They didn't store much energy, and the service life of a lead-acid battery wasn't good. LiFePO4 seems vastly better. Greater energy density, faster charging, longer service life. A 1 kWh station might supply basic household needs (not hot water), for 12 to 24 hours. They can be charged to 80% in maybe 50 minutes. This would demand power up in a range where a small gas generator is fairly efficient. It could give you emergency power 100% of the time while reducing fuel needs 90%. Fuel on hand would last 10 times longer.
I ordered a generator and a 1 kWh power station. The generator arrived first. They say on 2 gallons it will produce 3400 watts for 3.5 hours and 850 watts for 14 hours. That's 18% of the energy in the gasoline.
I put in a pound of fuel and weighed it on my package scale: 61.18 pounds. I ran it with no load for 12 minutes and weighed it again: 61.00. In grams, the difference was 81. I put water in a kitchen cylinder until it weighed 81 grams. When I put it on the generator, the package scale again said 61.18. It was verified. It had used 0.18 pounds of gas in 12 minutes. Two gallons would give me 13:20 unloaded, less time than listed 14:00 with an 850 watt load.
Wait. Before having hands free to start the stopwatch, I needed to pull the rope, then shut off the choke. If it had run 36 seconds before I pressed the stopwatch, it would agree exactly with a 14-hour run time. The delay was probably less, but the brief use of the choke would have increased fuel consumption. My figure for no load agrees closely with the published figure for 850 watts.
Each cycle of a gas engines needs a certain minimum of air and gasoline for complete combustion, to reduce air pollution. To keep an unloaded engine from overspeeding, the ignition module may retard the timing, for example. This seems to be why, as the load drops below 850 watts, fuel consumption doesn't drop.
My refrigerator needs 960 watt hours a day in winter and 1300 in summer. That averages 40 and 54 watts. Running the generator continuously to supply my refrigerator would require 3.4 gallons a day.
With three 40-minute charges a day, the power station could supply 1.75 kWh a day for the refrigerator and lots of other uses, and 3.4 gallons would last the generator 10 days. When fuel isn't readily available, fuel economy means peace of mind.
