The stated expiration date is technically the half life of the battery, IOW, theoretically, it could last an equal period of time after expiration. My experience is a year may not matter, but multiple years we start seeing failures. Also, you should run the self-test at least once monthly, it is rated for that, or if used infrequently, before taking it somewhere that it might be used.

I caution against using one of the do-it-yourself online battery replacements. OTOH, many folks do so with few reported issues. Just bear in mind that without a fresh gasket and pressure test, you have no idea how it will hold up under adverse conditions.

There's nothing much special about most of the PLB or EPIRB battery packs, they are just quality commercial cells assembled and shrinkwrapped. But, from the manufacturer you can be assured that the cells were sourced from a reliable vendor and exactly match all specs, not just the right size, and that it has passed stringent quality control checks.

Since we are talking about a life saving device, my recommendation is to err on the side of caution. The other alternative is to simply replace with new and get the latest generation device for admittedly more money.

Whatever floats your boat, YMMV, etc.
_________________________
Doug Ritter
Editor
Equipped To SurviveŽ
Chairman & Executive Director
Equipped To Survive Foundation
www.KnifeRights.org
www.DougRitter.com