I recently rescued an MGE 2200 VA UPS. The UPS has the batteries dead (extremely dead), as it has only 0.5V out of 72V (6x12V). Obviously, it has been unplugged for a while.
When I plug the UPS to the wall (with or without the battery connected). It refuses to turn on. No LEDs come up, no relay sound, nothing. Inspecting the PCBs, I found a corroded trace, which I have bridged, with no effect on the UPS's behavior.
I've read on some forums that this is normal, they refuse to turn up unless a valid battery is in place. However I am not willing to expend money on 6 batteries just to test whether this hypothesis is true or not. my question is about how I can test it. I have a working 2x12V battery pack from my current UPS. However, I'm afraid that if I plug them in, they might get damaged. Furthermore, 24V might not be sufficient. Another thing I've thought about is trying to charge those 6 dead batteries, in groups of 2 with my current UPS.
Do you recommend any of these 2 tests? What other alternative can I try?
Edit: the UPS seems to have been manufactured in 2002. Manual of the UPS: https://www.manualslib.com/manual/467056/Mge-Ups-Systems-Pulsar-Evolution-2200.html?page=8#manual
Edit2: What's the brand reputation of MGE, it seems like now its property of Eaton. My current UPS is from Eaton, although linux recognizes it as a MGE UPS. It has served me OK for the last 2 years