Generator Question?
How big of a generator do I need to run my 15K BTU air conditioner? Assuming I may also be running a coffee pot or microwave at the same time.
Forum Discussion
If it is the Coleman Mach series, the manufacturer recommends 3.6/4 KW, for the protection of the A/C from low starting voltages. Yes, the 15K goes on a 20 amp branch circuit, draws 14-17 amps running, but might double or triple that briefly while starting the compressor.
Hooked up to power, this is a surge and brief voltage drop. Hooked up to a conventional genset, this surge is handled by trading rotational energy for extra power, slowing the generator briefly. Inverter gensets, if large enough, might not even sag the voltage (if not running in economy mode). Some will overspeed to briefly supply more than the rated power. In either type, the protective circuitry in the generator has to allow the surge, and if sized too small the surge will prolonged and the generator more likely to disconnect or even shut down.
I know campers who have gotten away with using the Yamaha EF3000ISEB for a 15K A/C, while the EF2400IS (nominally 20 amps) couldn't handle an A/C that large. One brand might work while another might not, and within brands, different models of the same nominal size have different surge capabilities. In the smaller sizes, it is best to look for something offering a "boost" feature.
Hooked up to power, this is a surge and brief voltage drop. Hooked up to a conventional genset, this surge is handled by trading rotational energy for extra power, slowing the generator briefly. Inverter gensets, if large enough, might not even sag the voltage (if not running in economy mode). Some will overspeed to briefly supply more than the rated power. In either type, the protective circuitry in the generator has to allow the surge, and if sized too small the surge will prolonged and the generator more likely to disconnect or even shut down.
I know campers who have gotten away with using the Yamaha EF3000ISEB for a 15K A/C, while the EF2400IS (nominally 20 amps) couldn't handle an A/C that large. One brand might work while another might not, and within brands, different models of the same nominal size have different surge capabilities. In the smaller sizes, it is best to look for something offering a "boost" feature.
