Is APC Battery Backup Flashing Red and Green? Find Solutions Here

apc battery backup flashing red and green

Every APC unit houses a backup battery in case the primary battery fails to protect file integrity should battery failure take place. But what happens when the APC backup sends out distress signals? If you’re confused about the lights or tones that your backup is presenting, we are here to explain those different signals and how to correct the problems at hand. 

Why is My APC Battery Backup Blinking?

The APC backup battery indicates an ultra-low battery level by simultaneously flashing all of the hardware’s lights. Generally, blinking APC backup lights announce that the backup battery’s run time is five minutes or less. 

Aside from a failing power level, these flashing lights can also indicate poor calibration time or a system overload. Of course, it’s possible that if your APC backup is fresh out of the box, it just needs more time to charge, but it could also tell you that you need a full battery replacement. 

Why Does APC Blink Green and Red?

The alternating flashing of green and red lights on the APC generally announces that the hardware has gone into “sleep” mode or something similar to conserve the remaining battery power. 

System designs usually have safeguards in place that include the internal operating being able to gauge the battery life and perform a refined system shutdown before total failure, which puts the system at risk. 

These safeguards commonly come in the form of automated diagnostic tests that the hardware periodically runs on itself to prevent file damage. When a full diagnostic runs and flags a low battery, it triggers the flashing red and green lights on the APC backup to alert the user that the battery needs attention.

APC battery backup flashing red and green: Solutions

APC Battery Backup Flashing Red and Green: Solutions

Powering down the full UPS system is the first step to solving whichever problem the flashing LED lights are signaling. If it’s a total system overload, you might need to end some of the operating tasks that are currently running and then power down the unit before restarting to fix the problem. 

Depending on your specific system, the total power-down time you allot varies. Some systems will recalibrate and reboot to full functioning within ten minutes of shutting down, and some take up to an hour or even more. 

Temporary overload is much more likely to be the suspect in a backup battery that is less than five years old than a need for total replacement. A complete shutdown, substantial cool-off, and slow reboot often is the remedy for these warning lights. 

If you’ve gone through the entire gradual shutdown-to-restart process and you’re still seeing these flashing green and red lights, you may need to consider the replacement of the APC backup battery. 

APC Flashing Red and Green and Beeping

The alternating flashing of red and green LED lights combined with a consistent beeping is usually a warning of battery failure or disconnect. 

The battery terminals can come loose, which causes a disconnect and a resulting loss of power. You can often resolve this issue by double-checking the connectivity and ensuring that all of the hardware is securely fastened. 

APC green light blinking twice

APC Green Light Blinking Twice

The first thing that a blinking green light could indicate is a system overload and that the equipment is attempting to find a new power source. It could also be flagging an internal operating fault that requires the replacement of the entire unit. 

Some systems are compatible with add-on hardware that can serve as extensions of the unit and can prevent or delay shutdowns. If you’ve let the automatic calibration run or have connected extensions and you’re still getting this warning, you might need to run a manual runtime calibration.

The internal microprocessor might require a reset in this process to properly adjust the operating system and resolve the backup battery failure signals. This tends to work better with newer systems. Older technology cannot usually recalibrate with this level of intervention.

APC UPS Beeping Continuously Red Light

This type of alarm commonly signals that the battery is surpassing its designated temperature limit and will not stop beeping until the internal temperature reaches a safe range for a consistent time frame of around five minutes. 

This often happens when too many different pieces of equipment draw power from a singular unit. You might need to unplug some device attachments to improve the power of the APC and reduce the electrical current that’s too demanding on it for it to cool down and operate healthily. 

How Do I Know if My APC Battery Backup is Charging

How Do I Know if My APC Battery Backup is Charging?

Most units come with LCD screens that have charging meters to display not just the battery level but also the estimated runtime. You might have to press the main button that pairs with the LCD screen a few times to change the display until it reaches the power and battery life portion. 

There is also brand-specific software from the manufacturer that should allow you to run diagnostics and access information concerning the battery level and runtime expectations. If the software is not pre-loaded with the equipment, you can generally download it directly from the manufacturer’s official website. 

How Do You Calibrate APC After Replacing the Battery?

The unit’s battery has to be fully charged at 100% power capacity to recalibrate properly. Professionals recommend allowing the unit to charge for a full 24 hours before attempting the calibration process.

Disconnect the UPS communications cable and unload the battery from the unit before unplugging the UPS completely. Remove all attached devices and let the unit charge while turned off for around eight hours before turning it back on, reattaching the battery and additional devices. 

How do I reset my APC battery backup

How Do I Reset My APC Battery Backup?

Make sure that nothing connects to the UPS’s communication port. Then, complete a full shutdown and unplug the unit. Then, turn it back on and reconnect the computer to start an internal battery check via the internal operating system. 

Use a HyperTerminal session to click the correct serial port and check the connection using the Shift+Y keys. Type the *1* key, wait a few seconds, type it again, and click the *0* key to verify that the present battery life matches the number the system automates in response. 

You can close the HyperTerminal and recheck the runtime to ensure it reflects the renewed power expectancy. 

Is My APC UPS Under Warranty? 

APC UPS products have coverage under a warranty that promises them to operate free of defects in both workmanship and materials for three years from the purchase date. Batteries have warranty coverage for two years from the purchase date. 

This warranty only applies when the consumer registers the product officially within ten days of purchasing. Restrictions on the warranty include an assessment of the defects that show the consumer or a third party is the cause of the damage and not the manufacturer. 

Theft, exposure to the elements, improper installation, and acts of God also do not fall under the conditions of the warranty. 

Final Thoughts 

If you have problems with your APC backup battery flashing red and green and beeping or APC backup blinking red or green, there are a handful of reasons you could be receiving these warning signals. 

Go through the paths to remedy that we suggest, and if all else fails, contact the manufacturer directly and see if you can gain assistance troubleshooting your device or determining what part of the equipment might require replacement. 


Why is APC light red?

A red light indicates the battery is disconnected. 

Why is my APC blinking green?

Blinking green light means the battery is about to run down.

How do I know if my UPS battery is faulty?

The battery should flash and make a warning sound. 

How do I know when my APC is fully charged?

You can plug the phone in and check the read-out.