Buying a defibrillator is the straightforward part. Keeping it ready to use, that's where most organisations fall short.
AEDs don't need much attention day to day, but there are three things that expire: the battery, the electrode pads, and the device itself. Miss any of them and your AED could fail at the worst possible moment.
Here's what you need to know.
How long does an AED battery last?
Battery lifespan varies between manufacturers and models, but most AED batteries last between two and five years in standby mode — even if the device has never been used.
| AED model | Battery lifespan (standby) |
|---|---|
| ZOLL AED Plus | Up to 5 years |
| ZOLL AED 3 | Up to 5 years |
| Cardiac Science Powerheart G5 | Up to 4 years |
| Cardiac Science Powerheart G3 | Up to 4 years |
Most AEDs run a daily or weekly self-test and will display a warning indicator if the battery is getting low. But it's worth noting these self-tests have limits — they confirm the battery has enough charge to run the test, not necessarily enough to deliver a full rescue shock when you need it.
Don't rely solely on the indicator light. Keep a record of your battery install date and replace it proactively before it hits the end of its rated lifespan.
How long do AED electrode pads last?
Electrode pads (also called defibrillation pads or shock pads) have an expiry date printed on the packaging, typically between two and four years from manufacture.
The gel on electrode pads can dry out over time, which affects both adhesion and the quality of the electrical contact. An expired pad may not deliver the shock effectively or may not adhere properly to the patient's skin.
Check the expiry date on your pads at least every six months. Replacement pads are straightforward to order and relatively inexpensive compared to the cost of having your AED fail in an emergency.
Most maintenance kits include a replacement battery and pads together, which makes it easy to keep both current at the same time.
How long does the AED itself last?
The device itself typically has a manufacturer-recommended service life of around eight to ten years, though this varies. After this point, the manufacturer may no longer guarantee the availability of replacement parts or firmware updates.
This doesn't mean the device stops working overnight; many AEDs remain functional beyond this period. But for workplace compliance and governance purposes, most organisations replace devices within the recommended lifespan.
If you're unsure how old your AED is, check the serial number on the back of the device and contact your supplier. They can confirm the manufacture date and advise on replacement timelines.
What does AED maintenance actually involve?
Day-to-day, AEDs are designed to look after themselves through automated self-checks. But responsible ownership means doing three things:
1. Visual checks
Once a month, check that the device is where it should be, the status indicator is showing green (or the equivalent ready signal for your model), and the pads and battery are within date.
2. Keeping records
If you're a workplace or organisation, you may need to demonstrate compliance in the event of an audit or incident. Keep a log of your visual checks, battery replacements and any callouts.
3. Annual servicing
A professional AED service — carried out by a qualified technician confirms the device is functioning correctly, the software is up to date and consumables are within date. It also provides a service certificate, which is useful for compliance purposes.
ZOLL AED maintenance — what to know
ZOLL AEDs are among the most widely used in the UK. Here's what to keep in mind:
ZOLL AED Plus uses a ten-pack of Type 123 lithium batteries rather than a sealed battery pack. These are straightforward to replace and widely available. The CPR-D·padz adult pads have an expiry date on the packaging — typically around two years from opening.
ZOLL AED 3 uses a single sealed battery pack rated for up to five years in standby. Electrode pads are the Uni-padz Universal III, which cover both adult and paediatric use from a single set — worth noting if you're managing replacement schedules, as you only need one type in stock.
Both models benefit from ZOLL's PlusTrac remote monitoring service, which sends alerts when the device detects an issue — removing the reliance on manual checks.
Cardiac Science maintenance — what to know
Cardiac Science Powerheart G5 uses a non-rechargeable Intellisense battery rated for up to four years. The G5 performs daily self-tests and will display a warning if it detects an issue. Electrode pads are model-specific — make sure you're ordering Intellisense pads, not standard G5 pads, if your device has the ICPR feedback function.
Cardiac Science Powerheart G3 uses the yellow Intellisense lithium battery, also rated for around four years. Replacement pads are available in adult and paediatric variants. The G3 is an older model — if yours is approaching or past eight years old, it's worth discussing replacement options.
Managed servicing — is it worth it?
For most organisations, a managed AED service plan takes the guesswork out of compliance. Instead of tracking expiry dates yourself, a service plan covers remote monitoring with automatic alerts, annual professional servicing, consumable replacement reminders and compliance documentation.
Our PlusCare servicing plans are designed to make this as straightforward as possible. Whether you have one AED or a fleet across multiple sites, we can keep everything current and compliant.
Quick reference: AED maintenance checklist
- Monthly — visual check, confirm status indicator is green, confirm pads and battery are in date
- Every 2–4 years — replace electrode pads before expiry (check packaging for exact date)
- Every 4–5 years — replace battery pack (check manufacturer guidance for your model)
- Annually — professional service and compliance check
- Every 8–10 years — consider device replacement
If you're not sure about the status of your AED, or you need replacement pads, batteries or a full maintenance kit, get in touch with our team — we'll point you in the right direction.
