If your APC Back-UPS 900 (BR900) is chirping, beeping and cycling through all the lights, it’s not a battery issue, it’s a board problem. The cycling, chirping and relay noises are indicating that the unit had a board failure. This isn’t repairable, the unit needs to be replaced. If the batteries in the unit are fairly new (less than 3 years) then you could save some money by replacing the core of the unit and using your batteries.
Get in touch with us to see if we have a refurbished BR900 in stock. If we do, we can sell it to you without the batteries.