Light meaning and fix
APC Back-UPS Green On Line Flashing and Yellow On Battery Solid
On APC Back-UPS guidance, a flashing green On Line LED with a solid yellow On Battery LED means the UPS is performing a battery self-test.
On APC Back-UPS guidance, a flashing green On Line LED with a solid yellow On Battery LED means the UPS is performing a battery self-test.
What it means
The UPS is testing the battery. If the test passes, the green On Line LED should return solid and the yellow On Battery LED should turn off.
Device details
| Device type | UPS battery backup |
|---|---|
| Brand | APC |
| Model | Back-UPS LEDs |
| Light name | Green On Line LED and Yellow On Battery LED |
| Light location | UPS front panel |
| Color | Green and yellow |
| Pattern | Green flashing with yellow solid |
| Severity | info |
| Last verified | 2026-05-02 |
What to do first
Wait for the self-test to complete.
- Leave the UPS powered on.
- Wait for the self-test to finish.
- Do not disconnect protected equipment during the test unless needed.
- Check whether the green On Line LED returns solid.
- If the red Replace Battery LED turns on, follow APC battery guidance.
- Contact APC support if the test fails repeatedly.
When this can be normal
This can be normal during a battery self-test.
When to stop troubleshooting
Stop if the Replace Battery light turns on or if the UPS reports an internal fault.
Parts or products that may help
Only replace parts when the light pattern and official guidance support it. Some lights indicate setup or software states, not broken hardware.
- No replacement part is recommended from this light pattern alone. Troubleshoot the device state first.
FAQ
What does green flashing with yellow solid mean on APC Back-UPS?
Schneider Electric says the UPS is performing a battery self-test.
What happens if the test passes?
The green On Line LED should go solid and the yellow On Battery LED should turn off.
What if the red Replace Battery LED turns on?
The battery may need attention or replacement after the self-test.
This guide is based on: Schneider Electric APC Back-UPS LED FAQ.
Source type: official_support_page. Confidence: verified. Last verified: 2026-05-02.
APC LED behavior varies by Back-UPS model.