When should I replace the batteries in my defibrillator?

When it comes to using a defibrillator in an emergency situation, every second counts. Having a defibrillator (AED) nearby means the patient can be treated quickly, but only if it’s fully functional. A commonly overlooked aspect of AED maintenance is battery replacement. 

In this blog, we’ll explain how often you need to replace defibrillator batteries, the typical lifespan and how to ensure your device is rescue-ready when it’s needed. Whether you’re looking after a defibrillator in a school, workplace, gym or community setting it’s important to regularly check that your defibrillator is in full working order. 

Why do you need to replace defibrillator batteries?

Your defibrillator needs a functioning battery to be reliable when it’s needed in an emergency. A low battery means the AED won’t be able to deliver a life-saving shock when it’s most needed. Routine battery replacement is essential to:

• Ensure your defibrillator is always operational
• Avoid device failure during a cardiac emergency

How long do AED batteries last?

AED battery life varies by brand and model but most offer a standby life of two to five years. Here’s a quick breakdown for popular defibrillator models in the UK.

Always refer to your device’s user manual and manufacturer guidelines for accurate battery lifespans. 

5 signs it’s time to replace your defibrillator battery

Here are the key signs it might be time to replace your defibrillator battery to keep it fully operational.  

1. Battery expiry date approaching 

All AED batteries have a ‘use by’ date printed on the unit. Make a note of this date and ensure you replace the battery by this date. Never wait until the battery fails.

2. Low battery warning indicators 

Most defibrillators will emit a beep or show a red light when the battery is low.

3. Audible alerts or error sounds 

If your device is beeping or making irregular sounds, it probably needs a battery check or replacement.

4. Device failed self-test 

Many AEDs run automatic diagnostics. If a test fails, the device may display a warning related to the battery’s power.

5. Post-emergency use 

If your AED has been used in an emergency, the battery (and pads) may need to be replaced, however, most modern AED’s are designed to be able to deliver hundreds of shocks before depleting the battery.  As such, the battery may not need replacing- ultimately.

For more information on defibrillator pads and why they expire, read our blog.

How often should you replace defibrillator batteries?

Here are the key times you need to replace your defibrillator batteries:

• Every four to five years depending on the defibrillator model (or sooner if recommended
• At the first sign of a warning or alert
• Always before the battery expiry date

If your defibrillator is installed outdoors (e.g. in a public access cabinet), UK weather conditions can also affect battery life. Cold temperatures can drain lithium batteries faster, so regular checks are even more important.  

How to stay on top of defibrillator battery maintenance

Keeping your AED battery in check doesn’t have to be complicated. With a few simple steps, you can ensure your defibrillator is always ready for action in an emergency. 

1. Log battery installation and expiry dates 

As soon as you install a new battery, write the installation date down along with the manufacturer’s expiry date. Keep this record in two places: one physically close to the device (on a tag or wall sheet) and one digitally (on a spreadsheet or calendar). This is especially important for public access defibrillators or shared devices in schools, gyms or workplaces.

2. Set digital reminders for battery replacement 

Use Google Calendar, Outlook or any scheduling app to set automated reminders at key milestones:

• 6 months before the expiry date (to order a replacement)
• 3 months before (to install the new battery)
• Monthly visual check reminders 

3. Perform monthly visual checks 

Regular checks are quick but essential. At least once a month inspect your defibrillator for:

• A ‘ready’ status indicator (a green light, check mark or visual symbol
• No flashing red lights or audible alerts
• No visible damage to the battery compartment or device 
• Clean, dry and unobstructed cabinet or carry case

If your defibrillator shows a fault or warning, refer to the manual or contact the manufacturer or supplier for troubleshooting and advice.

You can opt for a Defibrillator Maintenance Check Every 6-8 weeks if you want peace of mind that your defibrillator maintenance will be taken care of and ready for use when it’s needed. 

4. Keep spare batteries on-site 

Always keep at least one spare battery on hand, especially in remote areas or setting where quick delivery may not be possible. For critical environments such as GP surgeries, care homes or leisure centres, consider holding a full backup pack with pads and batteries included. 

5. Register for alerts from the manufacturer 

Some AED models and brands offer automated battery and pad reminders via text or email if you register the device online. Register your AED with the manufacturer as soon as its installed to activate this feature and benefit from warranty updates or software recalls.

When you purchase a defibrillator from Defib4Life, we will provide you with reminders when both your pads and batteries are due to be replaced.

6. Train staff or volunteers to recognise battery warnings 

Ensure everyone who may use or inspect the AED knows what battery warning indicators look and sound like. Share a simple guide or create a laminated checklist for quick reference.

Where to buy replacement defibrillator batteries in the UK

If you’re looking for a reliable source of replacement defibrillator batteries, at Defib4Life we stock genuine manufacturer-approved AED batteries compatible with all leading defibrillator models.

You can browse our full range of replacement AED batteries here.

Don’t wait, check and replace defibrillator batteries regularly

Staying on top of battery replacement is one of the simplest and most critical steps in maintaining a defibrillator. Here’s a quick summary:

Replace batteries every four to five years or as directed by the manufacturer, respond immediately to warning lights and always check batteries after the defibrillator has been used. 

At Defib4Life, our mission is to make sure that life-saving defibrillators are available when they are needed most- whether that’s in schools, sports facilities, workplaces or public spaces. Take a look at our replacement batteries here. If you’re not sure which battery fits your defibrillator, our friendly customer service team is happy to help. Contact us today.