[Nut-upsdev] eco mode insight, maybe

[Greg Troxel]

I was looking at the manual for a cyberpower CPS1500AVRLCD3:

  https://m.media-amazon.com/images/I/A1-K2cO6SbL.pdf

and noticed they call this "GreenPower" which is probably one of many
flavors of ECO :-)

In this case, they say that they don't power the transformer in normal
operation, persumably switching with relays to power it for voltage step
up/down during low/high voltage, and turning on the inverter for missing
voltage.  Obviously they must have some power supply for control
electronics and maybe trickle charge of the battery.