APC UPS SUA1500I reporting itself as 3000RM

[hulubei]

Hello,

I had this UPS off for some time. I have opened it to check batteries, one 12.3v the other 8.5v. I had another one showing 12.7v around so I have changed the bad one with this one. Turned the UPS on and all was good until I did the self test on which the UPS shutdown unexpectedly.

I then have checked PowerChute and discovered the detected model was in fact shown as 3000RM. I was using the USB cable to connect. 

There is no network card.

I have made the serial cable using the information from here: https://beardedmaker.com/wiki/index.php?title=APC_Smart-UPS and was prepared to see what I can do reading posts here about some resets.

I tried to connect from a Windows laptop using USB-Serial UC 232A convertor. I was using Putty and 2400-8-1-none-none settings and I am getting to black screen only. Using 9600 baud is doing exactly the same. UPS was online, powered on and having some small load.

Any help please to understand what are the steps I miss to connect to the UPS and correct the model and presumably the battery voltage it expects. Even Nominal Battery Voltage (48v) and reading of Current Battery Voltage for 54.4 is wrong and can not be true.