Once you slide the new batteries in,
the UPS will still think it has dead batteries because the internal microprocessor stores old degradation metrics.
You must force a calibration test to reset its brain.
Prerequisites Before Calibrating:
- Charge for 24 Hours:
- Plug the UPS in and let the new batteries charge completely to 100% before doing anything else.
- Apply a Stable Load:
- Plug a non-critical load (like a couple of dummy box fans or a space heater) into the UPS.
- The load must be at least 30% to 50% of the UPS capacity and must remain completely stable throughout the test.
- Do not use your Unraid server for this test, as the power will cut out completely.
Step-by-Step Calibration Methods:
Method A: Via the Web Network Management Card (Recommended)
Since your system is using the PCnet driver via Ethernet, your UPS has an AP9630 or AP9631 Network Management Card installed inside it.
- Type the IP address of your UPS into your web browser.
- Log in (default credentials are usually
apc/apc). - Navigate to Control > UPS > Initiate Runtime Calibration.
- The UPS will intentionally switch to battery power and drain the batteries down to roughly 10% to measure the new cell capacity before switching back to utility line power automatically.
Method B: Via the Terminal (If Web Card Access Fails)
You can command the apcupsd daemon inside Unraid to run the test.
- Open a Terminal to server
- Stop the background daemon by typing:
/etc/rc.d/rc.apcupsd stop - Run the interactive diagnostic tool by typing:
apctest - Select the option for Run Runtime Calibration.
- Follow the terminal prompts. Once completed, exit the test program and restart your daemon using:
/etc/rc.d/rc.apcupsd start
Once completed, the STATUS flag in your Unraid panel will clear out the REPLACEBATT error and reflect a healthy, accurate runtime estimate.