While the principle of an electric generator has been areound since the early 1800s, the idea of a useful hand portable electric generator required the development of a lightweight device. Early ones were as simple as a motor driven generator and date to the early 1900s, & by the 1930's, small wind powered generators such as made by Zenith were common in rural areas. Like modern counterparts for camping trailers these generally were used in conjunction with battery banks however the concept of a hand portable gasoline generator or genset really dates to the post-WW2 period.As near as I have been able to determine, the first commercially successful, hand portable genset was the Honda E300 in 1965.
However while hand portable, these produced a signal much closer to a square wave than a sine. Fine for hard electric devices, they wreaked havok with electronics which remained battery operated. Radios had a particular problem and when powered by such a genset often produced very loud staic. Honda was soon followed by Yamaha which also produced generators but which were also not suited for electronics.
This changed in 1998 when Honda (EU series) and Yamaha (EF series) came out with generators for the US that offered much more stable voltage and frequency also with waveforms much closer to a sign wave. "Under 2% Total Harmonic Distortion" became a standard that moder electronics could accept.
Hovever it was the Honda EU9i that brought forward the hand portable form factor of modern systems though still less than 1KW, larger units were still in square "contractor profile" two-person-lift units.
Illustrating the advances in stable sine wave output made possible by the Generator>Rectifier>Alternator devices having microprocessor control is shown in this chart from Honda:
In 2001 the EU16i was introduced and this was the first appearance of the modern EU2000i. In fact both are rated at 1600W continuous and both use the same GX-100 engine. Two of the hallmarks of the EU2000i also appeared on the EU16i, the breather valve on the gas cap and an "Eco-Throttle" low power setting for extended duration on a tank.
Reguardless it was this introduction that set the stage for all of the successive knockoffs from every company imaginable and mostly with the same 2000W/1600W rating. Meanwhile Honda was secure as the acknowleged "standard of the world" and had little reason to change a winner. The 2016 EU2000i is very little different from the EU16i down to the same engine. If a consumer needs more power, they can add another EU2000i and parallel them.
In the meantime, some of the knockoffs have advanced beyond Honda in rated power, lower noise, lower fuel consumption, lighter weight & lower TCO while several are in the 2500W area that is becoming very important for campers who need Air Conditioning but have little space for more than one generator. It will be interesting to see what Honda does to address the competition.
To see more of my testing of lightweight generators that can run an AC, go to my shootout page.