My question in buying one used and replacing the batteries is, how do I know it was stored properly and will work when my life depends on it?

I have bought a lot of slightly used gear but I stay away from used electronics for the back country.

If there is a way to be sure it will work I'm listening...

The engineering problem for smoke alarm batteries is very different than the one for a PLB. A PLB requires much more power and is subject to wildly different environmental factors in terms of temperature, pressure, water, dust, shock, and movement. A smoke alarm has a test mode that does not activate a worldwide rescue system. A PLB would probably have to be a lot bigger to hold enough AA batteries to reliably have enough power compared to the batteries they use today.

I am not saying it could not be done, especially with CR123A lithium primaries and a different form factor, but it is not the same engineering problem as a smoke detector.

I'm pretty sure AEDs have user replaceable batteries.

Hi,
There is talk of a self-test feature,
a switch/button on the device

some devices offer a paid subscription service with free 2 day triel, to get a email/sms when performing a test , see 406link.com

Hi,
What are you talking about? A 10 year plb?

I used smokealarm as an example of a lifesaving device with replacable batteries,
since PLBs already have those,
and yes they are CR123A LiMnO2 (Lithium Manganese Dioxide)
The website to go along with video above is
new-batteries-for-a-sarlink-plb

All I meant is that the engineering problem for user replaceable batteries is very different for a PLB than for a smoke detector.

Personally, I think a flashlight-like form-factor of a tube with the batteries in series would work well for a PLB, but I've got too much to do to learn enough to design a competing PLB.

Glad I asked. Thank you for the info and link!

The website is good to check out for anyone owning or thinking of owning an ACR or ARTEX PLB.

I'm thinking of the jury's reaction. Smoke alarms are, as you say decades old, and people are very familiar with them. I see it being argued that PLB's are "new" "exotic" "complex" etc. and therefore require "expert" maintenance, including, for example, battery replacement.

Analogy's to other equipment, smoke detectors, AED's and probably other examples would be argued, but are not definitive and guaranteed proof and protection. Neither are licencing agreements, no matter how strongly worded.

Even if the manufacturer wins, it is expensive and they still get bad publicity of allegedly designing faulty/defective equipment that "killed people." And if they lose, it gets really expensive.

Better to avoid the risks with "non-user replaceable" batteries. That would be my recommendation, anyway.

Too late look at the picture, that's already a regular user replaceable battery right there

In fact , it looks very close to hotel door lock battery packs "Saflok 54240 6V Lithium" which are commonly priced under $10, even as low as $4

The connector might be different though, not a "Molex Micro-Latch (51065-0200 housing + 50212-8100 connectors)"
Some other PLBs use 9volt packs
...
I'd bet wherever you live there is a small shop (or a person) that would take such a small job for well under $150

I have a conversation today with ACR. I understand their position on why they want to service their products. In addition to changing the batteries the unit is then tested for water entry and checked to ensure it complies with the Cospas-Sarsat certification the unit was issued when submit for certification. Plus another way to look at the cost of a $130 (or so) battery replacement is that the unit is good to go for another five years which comes out to $26.00. Also if the PLB is activated for an emergency ACR will replace the batteries for free or provide a brand new unit.

I would like to state that I do not recommend anyone to do their own battery build to service a PLB.