Nihon Kohden 3100 Automated External Defibrillators (AEDs) perform regular self-checks to ensure they are ready to use in an emergency. If your defibrillator is beeping even though the battery still shows charge, it usually means the device has detected something that needs attention.

Below are some of the most common reasons this can happen and what you should check.

1. Check the Expiry Date of the Defibrillator Pads

One of the most common causes of a beeping AED is expired defibrillator pads.

Many devices will trigger an alert if the pads are out of date because expired pads may not perform correctly during a cardiac emergency.

For example, P-740K defibrillator pads must be replaced before their expiry date to ensure the device remains fully operational.

What to do:

• Open the AED and check the expiry date on the pad packaging
• If the pads are expired, replace them with a new set
• Once replaced, the alert should stop (replacement pads)

2. Consider Whether the AED Has Been Used for Training

Another possible reason for the alert is battery drain from training use.

If the defibrillator has been used regularly for demonstrations or training sessions, the battery may be draining faster than expected.

Even if the battery indicator still shows charge (for example 75% remaining), repeated use can sometimes trigger device alerts.

Signs this may be the cause:

• The AED is used regularly for training
• The battery has experienced frequent charge cycles
• The alert began after training sessions

3. Device Logs Can Show Usage History

If you're unsure whether training use is affecting the battery, many AEDs allow technicians to download device logs.

These logs can show:

• Device usage history
• Self-test results
• Battery performance
• System alerts

In some cases, a technician or manufacturer engineer may need to assist with retrieving these logs.

4. When the Device May Need Repair

If:

• The pads are still in date
• The battery has not been heavily used for training
• The device continues to beep

Then there may be an internal fault with the AED.

In this case, the device may need to be returned to the manufacturer or authorised service centre for inspection and repair.

Keeping Your AED Ready for Emergencies

To avoid unexpected alerts, it’s important to regularly check:

• Pad expiry dates
• Battery status
• Visual status indicators
• Device self-test alerts

Routine maintenance helps ensure your AED is ready to save a life when it’s needed most.

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