Why Your AED’s Green Light Can Be Dangerously Misleading

Why Your Green Light Might Be Lying to You

A solid green light on your defibrillator feels reassuring. Many workplaces, schools, and community facilities see that glow and tick "AED ready" off the list without another thought. The problem is that the light can be telling only half the story, and in a cardiac arrest, half the story is not enough.

When someone collapses and the alarm is raised, the AED is grabbed, the lid is opened and everyone looks for simple, clear prompts. If the status light is green yet the device fails to deliver a shock, powers down unexpectedly, or boots up with error messages, precious minutes are lost. That is why we believe AED maintenance is just as important as buying the unit in the first place. The indicator light is one small part of a much bigger picture.

What the AED Status Light Really Checks

Most modern AEDs carry out automatic self-tests. These checks usually look at the internal circuitry, the battery connection and basic system status. If that internal check passes, the light stays green, which feels like a clean bill of health. But these tests are not the same as a full readiness review.

What the AED does not always check is just as important. Self-tests often do not measure the age, expiry or condition of electrode pads. They usually cannot tell if the gel is drying out or the packaging has been subtly compromised. They may also only look at whether a battery is present and connected, not whether it has the depth of charge to power multiple shocks and extended voice prompts.

To add another layer of confusion, different brands and models use different light patterns and beep codes. One unit might flash green for "OK" while another uses the same pattern to show "advisory" mode. Without basic training, staff can easily misread these signals, especially under pressure.

Some faults also only appear under real use. Issues with delivering energy, analysing the heart rhythm or recording event data might not show up during a quick internal test but can appear when the AED is actually attached to a patient. This is why we see the status light as one helpful tool, not a complete guarantee of safety.

Hidden Risks the Green Light Will Not Show You

Several quiet problems can sit behind a happy green light.

Expired or drying electrode pads are one of the most common. Over time, the adhesive can lose its stick and the conductive gel can dry out. The pads may still look fine in the packet and the AED may still report "ready", but when applied to skin they can peel away or fail to conduct properly. That can affect how accurately the device reads the heart rhythm and how effectively it delivers a shock.

Batteries have similar hidden traps. A battery can have just enough power left to pass an automated self test but not enough to:

• Deliver multiple shocks in a longer resuscitation attempt  
  
• Power loud, clear voice prompts for the full duration of CPR  
  
• Support data recording functions that might be needed after the event  

In a quiet office, that might never be noticed. In a real cardiac arrest, where several shocks and ongoing guidance may be required, it becomes a serious problem.

Then there are the simple, human details. The green light will not tell you if:

• The razor, scissors or CPR face shield are missing from the AED kit  
  
• The spare set of pads has been used and not replaced  
  
• The wall cabinet is blocked by furniture or locked with no key nearby  
  
• The AED has been moved to another area and no one updated the team  

Incorrect placement or poor environment can also work against you. Heat, dust and moisture can shorten the life of pads and batteries, even while the status light still shows green. Units stored in cupboards, locked offices or rarely used storerooms may be technically "ready" but practically useless when seconds count.

How to Build a Simple AED Maintenance Routine

The good news is that you do not need a clinical background to run a strong AED maintenance routine. A simple, consistent process is enough for most workplaces and facilities.

We suggest breaking it into two levels.

First, a quick weekly visual check:

• Is the status light showing normal "ready" mode for that model?  
  
• Is the AED in its correct location and easy to access?  
  
• Is the case, cabinet or wall bracket closed, clean and undamaged?  

Second, a more detailed monthly inspection:

• Check pad and battery expiry dates and log them in a register  
  
• Confirm accessories are present, sealed and in good condition  
  
• Make sure signage is clear and the area around the AED is unobstructed  
  
• Note any changes in environment, such as increased heat or dust  

Many organisations find it helpful to nominate an "AED champion". This is simply someone who takes ownership of the maintenance schedule, keeps records up to date and coordinates with suppliers when replacement pads, batteries or extra units are needed. It does not have to be a medical role, just someone organised and committed.

Bringing AED checks into existing WHS procedures also works well. You can add AEDs to first aid audits, evacuation drills and safety walkarounds so they are reviewed alongside fire extinguishers, first aid kits and other emergency equipment.

How Restart The Heart Helps You Stay Ready

At Restart The Heart, we focus on supplying AEDs and related defibrillator consumables to workplaces, facilities and first aid providers across Australia. Because we specialise in this space, we spend a lot of time helping teams understand what their particular model needs to stay genuinely ready.

Clear product information, especially around pad and battery compatibility and expected replacement cycles, makes planning easier for safety managers and first aid officers. When a unit is used in a real emergency, or when expiry dates are approaching, having access to replacement pads, batteries and accessories helps reduce downtime and keeps your AEDs in service.

We also see value in choosing defibrillators with indicators and prompts that your people can understand quickly. Simple status lights, spoken instructions and easy-to-follow diagrams on pads can all reduce hesitation in a crisis. When staff are confident using the device, maintenance conversations tend to improve as well, because people feel more connected to the equipment.

Our role is not only to supply products but to support a longer-term view of AED ownership. That includes helping workplaces think through where units should be placed, how many are practical for a site, and what sort of maintenance rhythm will actually happen in the real world.

Turning the Green Light Into Real Rescue Readiness

A green status light is reassuring, but it is not the whole story. Real cardiac arrest readiness comes from pairing that light with regular AED maintenance, staff who know where the device is and how to use it, and a reliable source of defibrillator supplies when parts need replacing.

If you are responsible for safety in your workplace or facility, a good starting point is simple. Confirm where your AEDs are, create a basic log of pad and battery expiry dates, schedule regular checks and note any accessories or consumables that are missing or close to expiry. From there, you can refine your routine and equipment choices over time.

With a bit of structure and the right support, that small green light can represent something far more meaningful. It can stand for a device that is not only switched on, but genuinely ready to help save a life when it matters most.

Keep Your Defibrillator Ready To Save Lives

Regular checks are the simplest way to be confident your AED will work when every second counts. At Restart The Heart, we provide straightforward AED maintenance support so you can stay compliant and prepared without the hassle. Let us help you set up a practical schedule, reminders and replacement plan for pads and batteries. Reach out today and we will guide you through the next steps to keep your device rescue ready.