APC BN650 M1 Flashing Red Light and Alarm Tone??

[Anonymous user]

Symptoms: When unit is turned on, it flashes green for ~15 seconds, then flashes red with alarm tone.

Background: Unit battery went bad and was replaced with a 3rd party battery "RBC154 Compatible Replacement Battery for APC BN650M1 by UPSBatteryCenter", purchased on Amazon. Symptoms occurred during power up.

Corrective Attempts: Replaced battery with a known-good APC battery from another BN650M1, but symptoms remained. Put the compatible battery in the second BN650M1, and it works fine.

Questions:

1. What, exactly, does the flashing red light with tone mean? It's not covered in the user docs.

2. Is there anything I can do to correct this situation, or do I need to buy a new unit?

TIA for any insights/advice!

[Anonymous user]

Symptoms: When unit is turned on, it flashes green for ~15 seconds, then flashes red with alarm tone.

Background: Unit battery went bad and was replaced with a 3rd party battery "RBC154 Compatible Replacement Battery for APC BN650M1 by UPSBatteryCenter", purchased on Amazon. Symptoms occurred during power up.

Corrective Attempts: Replaced battery with a known-good APC battery from another BN650M1, but symptoms remained. Put the compatible battery in the second BN650M1, and it works fine.

Questions:

1. What, exactly, does the flashing red light with tone mean? It's not covered in the user docs.

2. Is there anything I can do to correct this situation, or do I need to buy a new unit?

TIA for any insights/advice!