Let’s find the dead cell in my Eaton 5PX

Todays goals:

1. pull both the ups and the external battery unit (EBU).
2. While there, swap them so the UPS is on top.
3. Take photos of the wiring.
4. Disconnect each battery.
5. Measure it.
6. Replace anything not like the others.
7. Expecting 13V or so on most.
8. One should read way less.
9. Maybe. But the UPS is now charged to 100%

All cells in the UPS measure about 13.4V.

Next, the EBU. All aboutt 13.4 or 13.35V.

Everything reassembled. No action taken.