Hi,
Before moving on to hardware problems, I would like to clarify some issues.
As far as I know - these devices are discontinued.
You originally said the BAT's voltage was 41V, now you're saying 47V.
You can see the year of manufacture of the UPS in the first digits of the serial number (ASxxxxxx), and as a rule, the battery life is about five years.
If you did not turn on the UPS for a long time or disconnected the batteries for replacement, you will need to answer "YES" to the replica from the "NEW BATTARY" control panel, this will start the calibration mode.
The most common suggestion on the APC forum is to perform the "BRAIN DEAD" procedure, clearing all errors.
https://community.se.com/t5/forums/searchpage/tab/message? advanced=false&allow_punctuation=false&filter=location&location=forum-board:datacenter-forum&q=smt3000rmi2uIt
Will take quite a long time for the batteries to be fully charged.
You can see this on the control panel.
If you have an NMC AP9630-AP9631 network card installed, you can monitor the charging process and battery status via LAN.
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Did you turn on the charger autonomously and what voltage does it give out?
I don't have a diagram of this UPS model, probably all the batteries are connected in series and the charger has different parameters with the same circuit.
In addition to the main charger, there is also an additional charge "GREEN MODE".
Q914 and built-in MOSFET's diodes are used to recharge batteries when reverse current flows in the transformer.
https://www.eevblog.com/forum/repair/apc-smartups-overload/ APC####.pdf