On Fri, Mar 3, 2023 at 7:54 AM Roger Heflin rogerheflin@gmail.com wrote:
[...]
If you read about normal UPSes they are not normally designed to run 100% duty cycle (ie on battery for days, or fixing up a low voltage for days). So if you run yours at say 40% load it will probably survive under the higher duty cycle, but if you run it close to 100% load and it gets into cleaning up low voltages the UPS electronics may not survive long (ie if fixing the voltages for hours/days).
So if they end up running in that state for long periods of time (either because of adding bigger batteries--my UPS came with 12AH batterys but now has external 35AH ones) and/or extended low voltages various components may burn out.
There is also a setting on at least some UPSes that you can change so that it does not regulate the lower voltages (wider acceptable voltage range) and accepts those voltages as ok. I have done that with both of my UPSes because the default setting prevents the UPSes from charging when on a small generator, and would if the voltages was low but still good enough cause the UPS to keep fixing the slightly low voltages and possibly burn out.
I don't think the part about a generator is a good idea. Generators are usually wildly out of spec for Total Harmonic Distortion (THD). A generator under load can easily reach 15% to 20% THD. Meanwhile, electronics usually expect 3% THD or less. So you want the signal conditioned, and not passing directly through to the electronics.
Jeff