william dryden wrote:

"Miaowara Tomokato" <miaowara.tomokato@mount.samurai> wrote in message

[...]

The 200 watt version is about 60 dollars.  2 of those, with the small
batteries removed, and deep cycle marine batteries wired in will run 4
500 watt PC's for quite some time.

It might if you remove the covers, re-heat sink the power transistors in
the inverter and add a cooling fan.  Been there, tried that, fried the
inverter and all I did was add the battery to extend the run time on an
otherwise acceptable UPS.

Looking at those things, the thermal design is scary bad considering the high amps that get switched. They look to be designed for a few thousand hours of standby and perhaps only an hour or two active operation before meltdown!

Makes me wonder if the old motor-flywheel idea might be better for the high power stuff:

AC Mains motor -> driveshaft/clutch -> DC Motor -> driveshaft/flywheel -> AC Generator

where the DC motor charges and can be driven by a big battery. The clutch avoids powering back into the mains upon mains failure. The flywheel smoothes out the transition. A speed governor needs adding to keep the 60Hz or 50Hz output as required.


Do these exist?

Regards,
Martin