question

I stopped tests quickly because the needed minimum load is fairly high and higher than I can produce with efficient LED lights. I lit up my whole house and it wouldnt come on. But I have a TV that comes on after a power outage no matter what, that was enough load to keep the inverter on (stupid TV). So nothing gained. I run it solely with a fridge, that works.

With a TV I would be more concerned about reports of burned out electronics. As I understand it, the test pulse charges capacitors at basically short current in any charging and voltage regulating device ie TV, Laptop, phone charger, most everything electronic thats plugged in. They then discharge as mandated by electricians code of ethics and get charged shortly after again. Usually this happens only once evertime you plug it into a wall socket. So like ten times over the lifetime of a TV. Here it happens hundreds or thousand times a day. Eventually some little part from the cheapest vendor lets out the electric smoke it needs to run. A non electronic fridge doesnt mind eco mode from the voltage spike perspective, a too small inverter however might struggle to recover from the surprise to finally finding a willing drain. Any hesitation and the compressor stalls. At best it needs three times the power while being stalled than eco mode saved you beforehand, at worst the compressor motor burns out if that happens regularly.

I struggle to find actual use for this mode.

Capacitors do initially look like a short circuit when fed a step function voltage pulse. Then they decay to an open circuit. The amount of current that will go through the capacitor will be limited only by the impedance of the driving circuit - and an inverter has very low output impedance. Inductors do the opposite - they look like an open circuit and then decay to a short circuit.

It does sound like the Eco mode was designed for heavier, more robust loads than modern electronics provide - and in any case electronics with power management or sleep circuitry would both drive and be driven nuts by the inverter's constant searching.

The other way to switch an inverter on with a load is to backchannel the inverter switchon with something like a universal remote - pressing ON on the TV would initiate a sequence of commands - first, inverter on; then, TV on, and so forth. Could even draw less power than Eco mode.