When on emergency power my APC smart ups goes crazy

[michalzxc]

My network UPSs (APC Smart 1000) are unhappy with the quality of energy while on Inverter emergency battery power - attaching video, it gets instantly fixed when grid is connected - (it is making this loud noise while compensating)

I have Fox KH10.5

[Dave Foster]

When you are running on EPS, have you got a Neutral to Earth bond being made and is your Earth on a local rod ? - if not you will have floating Neutral and/or possibly floating Earth.

Have a look at these 2 posts,

viewtopic.php?t=139

Particularly the last post on this thread viewtopic.php?t=52