At what interval should batteries be replaced in a remote controller used for security purposes?

Question

I have a few remote controllers hidden around the house. One is in the bathroom. If the front door busts in and cops scream at me while I'm sitting on the toilet, I can press the button on the controller in order to cut the power to my computer, without having to physically rush in there and pull out the cord. Then they may not be able to open the computer up (it's physically locked), dump the RAM, extract my encryption key and then use it later to steal all my private data.

Since these remote controllers have such a narrow, single use-case, I never actually use them (thankfully), so I have no idea if they still even work. Of course, I can regularly test them by plugging in a lamp or something instead of the computer, but that really tells me nothing about how much power there is left, and may even drain the power that is left by testing them! I obviously want them to work the day they are actually needed. So even though they aren't being "used", they still probably slowly drain the batteries simply by being inside the controllers.

The battery kind is "CR 2032" and the ones I buy seem mid-range in terms of price. Not the most premium, but also not the cheapest possible ones.

How long should I dare to wait before I replace the batteries in them? Are we talking 3 years? 5? 10? Even longer? Even less? I only need some sort of ballpark number so that I can be reasonably sure that they haven't drained completely as to not work the day I need them to. Given the situation, I'd rather be safe than sorry.

PS: You don't have to point out that they can just remotely fetch any files from my machine through the network cable and Intel Management Engine, etc. I'm well aware of the hardware and software backdoors, but I'm simply trying to do what little I can to at least feel somewhat safe on a "practical" level, while waiting for there to appear some sort of secure computer/OS.

Answer 1

CR2032 batteries are common in quite a few remotes, as are CR2025 and other similar versions/sizes. Regardless of shelf life, once a battery is put into service, the shelf life becomes less important than frequency of use.

There is no practical means to measure remaining life. If you require maximum reliability, return the plastic shim to the battery compartment at the same time as you replace the battery with a known, new cell. Consider to also purchase a name brand cell rather than trying to save a dime or two. You may have forgotten that these devices ship with an insulator between one contact and the battery, to maintain the shelf life. Many of these packages will have the equivalent of a "best buy" date on the package.

To meet the considerations provided in your description, you would have to pull the shim in order to make the connection, but it would then have full battery life to execute your commands. Many of the remotes I've purchased recently have the shim extended from the battery compartment, making removal relatively easy. "Remove before flight," takes on a new meaning in this context.