This is the model for APC UPS: DL5000RMI 5U
I cannot remember the exact way to calibrate the SUA range (which includes the rebadged Dell versions) apart from using hyperterminal in a similar fashion to resetting battery constants.
I think a hyperterminal session, baud 2400, bits 8, parity none, stop 1, flow xon/off
Establish session, then press SHIFT+Y and if returns 'SM' then okay to proceed. Press 1, then again and should return with 'Prog'.
From here I cannot remember the exact process of keys, I think 4,5,6 & 0 are for the battery constants, x for battery date, b is for unit type, B is for battery float calibration, P for output power drawn, n for serial number, maybe m for manufacturing date.
The above could be wrong, has been years since I've tinkered with one.