Recently, I have to change an expired McMurdo E3 EPIRB battery. I never changed an EPIRB battery before but after understanding its internal structure, I am confident enough to try for the first time.

The replacement kit comes with a battery unit, a gasket, a silica gel package, new battery expiry date sticker and 8 pieces of new screws.

This is how the new gasket looks like. It is used to replace the existing gasket on the top/antenna housing

The screws comes with o-ring to ensure watertight integrity to the EPIRB unit

First of all, remove all the holding down screws around the housing useng a flat face screwdriver. Total of 6 screws if not mistaken.

There are 2 screws hidden behind the lanyard. Pull the lanyard holder to reveal the screws ports (2)

After removing all the screws, gently pull up the top/antenna housing to disengage it from the lower part of the unit. The printed circuit board can be seen after the top housing been removed.
The printed circuit board is been secured with 3 screws

Use the Philips screwdriver to remove the centre screw. Extra precaution not to lose the washer below the screw














Then remove the spacers by either removing screws from the bottom of the spacers or loosen the spacers with finger. There are washers below the spacers and should be careful so not to lose the washers

Slightly lift up the circuit board gently. The battery unit can be seen at the bottom of the printed circuit board.

Try to locate this 2 connections attached to the printed circuit board. One of the connection is to the battery unit and the other one is to the unit test button. Gently disengage the connectors from the printed circuit board.

Note there is an old silica gel package (white package) at the bottom of the printed circuit board.

Remove the previous silica gel and replace it with the new one which comes with the replacement kit. Use the double sided adhesive tape to ensure the new silica gel glued to the area. The purpose of the silica gel is to keep the internal area dry from moisture

With the printed circuit board removed, the battery unit is visible underneath it

Use a narrow head pliers to loosen the bolt that is securing the battery unit. There is a washer below the nut and be careful not to lose it.

After the nut is removed, the battery will slide out easily. There is a tiny shaft in the middle that secure the battery unit.

Change the gasket for the top/antenna housing

Reassembled it in the reverse order. Once it is reassembled, push and hold the test button for 10 seconds to ensure the EPIRB unit is in working condition and able to transmit.

Lastly, put on the new battery expiry date sticker on the EPIRB unit. The battery has a lifespan of 5 years.

Also the EPIRB casing should be updated with the new battery expiry date sticker.

Practical sailor blurb
We received the letter below yesterday from Practical Sailor reader Arnold Rowe. He was kind enough to let us share it (with some minor edits of his well-expressed and understandable ire), with the hopes of raising awareness of the limited service life of 406 EPIRBs. Having had a similar experience years ago with the torpedo-sized RLB23 (which set me back more than a $1,000 in the ’90s) I can sympathize. The now obsolete RLB23 is officially consigned to Practical Sailor’s Gear Graveyard, and I expect a series of other newly obsolete EPIRBs to join it.

As we move forward with Ralph Naranjo’s report on Personal Locator Beacons (PLBs) in the April issue of Practical Sailor magazine, we’ll also look at effective service life. Battery life has become an even more critical issue these days as ACR—and I assume other makers will follow suit—add non-emergency functions to their PLBs, like the AquaLink View PLB . According to ACR Electronics , the new unit is designed with fixed limits for non-distress messaging and tests, so that using the non-distress features will not tap into the required reserve battery life for distress alerting. We look forward to testing this product and hearing readers’ take on the messaging feature, as it raises some important questions regarding the purpose of emergency signaling devices.
By the way, some safety equipment dealers are offering trade-ins on old ACR EPIRBs, which should help ease the financial pain of replacement. According to Mr. Rowe, Avalon Rafts is one of them.
Finally, I’ll emphasize here again that it is very important that owners of EPIRBs routinely drop in at the NOAA beacon registration website to make sure all their data is correct and up to date:

Dear Practical Sailor,
I own an ACR Satellite 406 EPIRB, Product No. 2758, Category II/Class 2.  This unit is manually deployable. A date stamped on the side of the unit reads Sept 15, 1997. A sticker on the same side reads Serial No 5990, Date: 9605.
On April 13, 2006, I had the battery in this EPIRB replaced at my local ACR service center at a cost of $222.38. A statement on the back of the EPIRB reads “Battery must be replaced after emergency use or by: 07/2011.”
Yesterday I happened to be in my local ACR service center and they kindly checked out my EPIRB using their computer based system.  It immediately passed all tests with flying colors.
Upon completion of the successful testing I was informed that after the battery theoretically expires in July of 2011, they will not be able to install a new battery as ACR will not permit this, the contention being that the EPIRB has lived out it’s useful life as a piece of electronic gear and therefore can no longer be placed in service any longer. If I wish to continue having an EPIRB aboard my vessel, I will need to purchase a new unit!
My EPIRB is in absolute pristine condition.  I am perfectly pleased with my existing EPIRB and wish to keep it for many years to come.  Purchasing an EPIRB was not a trivial initial investment and I find it irritating that I am forced to chuck a perfectly adequate piece of gear at the manufacture’s whim.
Arnold Rowe
Riverside, Calif.