Generac IQ2000 (Long winded report)
First off I want to say Generac as a company was pretty responsive to deal with. They answered my calls and emails timely and professionally. What I did not like was all of the excuses I got from them...
Forum Discussion
I don't have a feel for how the engine design affects the performance of an inverter generator, but there are a bunch of other factors that IMO affect it just as much. One is the engine idle speed. In the eu2000i, when "eco" is turned off, the engine does not run at its full RPM, but rather at an elevated idle speed. A different generator that brings the RPMs up to maximum will have an obvious load handling advantage. Another factor is the amount of intentional overspeed. The eu2000i runs the engine "somewhat" faster than needed for its current load (I sense that the algorithm for this is one of the more closely guarded tech details). The amount of overspeed will affect how well an increased load is absorbed. The amount of rotating mass comes into play. A generator with a larger rotating mass will better absorb a load increase in the short term, followed by the larger mass working against the engine trying to increase its speed. How far the software will allow the output voltage to dip comes into play. Allowing an extended-time dip might result in a successful start for some devices, and a failed start and/or damage to others. The quality of the output waveform will affect some devices.
I've been able to observe some of these differences in a few inverter generators. One (that I returned) did a horrible job of voltage regulation with anything but slight load changes. When a significant load was applied, it would let the voltage drop to as low as 60, then overshoot on the recovery taking the voltage over 130. Similarly, when a significant load was removed, it would let the voltage go above 130, then overcorrect, letting the voltage go under 100. The eu2000i does a pretty good job in this respect, and I have another 800 VA inverter generator that is stellar. As long as the load is within the current capability of the rotating mass, the voltage holds rock-steady on load changes. The eu2000i's waveform is very good, and it does especially good holding the waveform with a bad power factor load. (I'm disagreeing with the Padgett information here). The 800 VA generator has a nice waveform with a resistive load, but when there's a bad distortion power factor (a trait of most power converters) the inverter does not do a very good job as it tries to maintain the sine wave peak that the load is pulling down. The result is a nasty high-frequency component on the top of the sine wave peaks, as high as 500 volts peak. The RMS voltage is ok, and so far none of my equipment has had a problem with this, but there must be something out there that won't work correctly because of the bad waveform.
My conclusion is that trying to evaluate inverter generators from their specs is close to being an exercise in futility, and the best choice for one person's needs might be a poor choice for somebody else.
I've been able to observe some of these differences in a few inverter generators. One (that I returned) did a horrible job of voltage regulation with anything but slight load changes. When a significant load was applied, it would let the voltage drop to as low as 60, then overshoot on the recovery taking the voltage over 130. Similarly, when a significant load was removed, it would let the voltage go above 130, then overcorrect, letting the voltage go under 100. The eu2000i does a pretty good job in this respect, and I have another 800 VA inverter generator that is stellar. As long as the load is within the current capability of the rotating mass, the voltage holds rock-steady on load changes. The eu2000i's waveform is very good, and it does especially good holding the waveform with a bad power factor load. (I'm disagreeing with the Padgett information here). The 800 VA generator has a nice waveform with a resistive load, but when there's a bad distortion power factor (a trait of most power converters) the inverter does not do a very good job as it tries to maintain the sine wave peak that the load is pulling down. The result is a nasty high-frequency component on the top of the sine wave peaks, as high as 500 volts peak. The RMS voltage is ok, and so far none of my equipment has had a problem with this, but there must be something out there that won't work correctly because of the bad waveform.
My conclusion is that trying to evaluate inverter generators from their specs is close to being an exercise in futility, and the best choice for one person's needs might be a poor choice for somebody else.
