What should I expect to find when I am measuring the output?  Its not clear that my DMM would be able to capture a brief change in voltage that might be enough to cause a computer to reboot.

Should I expect a big change in the output voltage when switching from battery back to AC power?

Thanks,

SV

Thank you for your reply.  I was able to measure a change in the output voltage when switching from AC-to-Battery power and when switching from Battery-to-AC power.  On AC power, the output voltage was about 13.3VDC.  On Battery, the output voltage would drop to battery voltage level, 12.75VDC in my case.  My computer would remain running when switching from AC-to-Battery power.  When AC power is restored, the output voltage would rise back up to 13.3VDC, hard to measure on my DMM but it seems that there was a ramp-up in voltage or the switch-over was noisy at the output.  This increase in voltage at the output would cause the computer to reboot.

I ended up installing an Drok DC Buck Converter (https://www.amazon.com/gp/product/B078Q1624B) between the output of 5310 UPS and the computer.  In my case, the computer would accept an input level of 10.4VDC – where the buck converter regulates the output to 10.4VDC to the computer and the computer does not see the output voltage swings from changes in AC power at the 5310 UPS.  With the buck converter in place, the computer operates as expected when the 5310 UPS loses and regains AC power.  The Buck Converter will allow the battery/input voltage to drop down to as little as 10.5VDC (just 0.1V difference needed for step-down, nice) for my 10.4VDC output, this feature helps protect the battery from being discharged too far and I maintain the expected battery backup time.

-SV