How Long Does an EPIRB Battery Last?
How Long Does an EPIRB Battery Last?
Two numbers matter for EPIRB batteries: the standby life and the operational life. They are very different things and both matter.
Standby Battery Life — 10 Years
The battery in a modern EPIRB maintains it in operational readiness for 10 years from manufacture while the device sits in its bracket, never activated. This is the standby life. After 10 years, the battery must be replaced even if the EPIRB has never been activated — the battery degrades over time regardless of whether it has been used.
The expiry date is printed on the device. Check it. An EPIRB with an expired battery is not a reliable piece of safety equipment.
Operational Life — Minimum 48 Hours
Once activated — in a real emergency or tested — the EPIRB transmits for a minimum of 48 hours. This is the operational life and it is the SOLAS minimum standard that all approved EPIRBs must meet. Many modern EPIRBs transmit for significantly longer.
48 hours of continuous transmission. In a real emergency scenario, this provides time for rescue services to reach even remote locations.
Battery Replacement
Most modern EPIRBs — including the Ocean Signal EPIRB1 and ACR GlobalFix range — have user-replaceable batteries. This means at the 10-year mark you can replace the battery and cylinder rather than replacing the entire EPIRB. This is a significant cost saving.
Some older EPIRB models required factory service for battery replacement. Check your specific model’s documentation.
What Happens If You Let the Battery Expire?
If your EPIRB battery expires and you never replace it, the EPIRB will at some point fail to transmit with full power and duration in a real emergency. It may still transmit initially but the 48-hour operational guarantee is void once the battery is past its expiry date.
An expired battery also flags during the self-test function — the EPIRB will indicate a battery fault. This is not a reason to replace the battery less urgently — it is a reason to replace it immediately.
Servicing Schedule
EPIRB battery replacement: every 10 years or at the expiry date marked on the device.
EPIRB general service: every 5 years at a manufacturer-approved service centre.
Self-test: monthly, using the built-in self-test function only.
FAQs
Can I use an EPIRB after the battery expiry date?
The device will still function initially but the guaranteed 48-hour operational life is compromised. In a real emergency this is a serious risk. Replace the battery before the expiry date without exception.
How much does EPIRB battery replacement cost?
For user-replaceable models — the battery and inflation cylinder together typically cost £100 to £200 depending on the model. Significantly less than replacing the entire unit at £250 to £600.
Does a partial activation drain the EPIRB battery?
The self-test function uses a minimal amount of battery power and is designed to be performed monthly without significantly affecting battery life. A full activation — if the EPIRB is accidentally triggered — does drain the battery. Check the battery status after any accidental activation.
Always replace EPIRB batteries before the expiry date marked on the device. Battery expiry dates and service intervals are in addition to the general EPIRB service requirements. Verify current requirements at gov.uk/mca.
