Your strategy of preventive  battery changing is totally thoughtful. But our problems had nothing to do with batteries, it has to do with an environmental issue that the alarms don't like. They can be sensitive to dust, bug guts, and a bunch of other things. To be honest, I don't understand what's gong on, but knew that having alarms I can't reach is a liability I didn't want to continue.

We have had that issue before.  It was a notification that the batteries needs to be replaced. I now replace all the batteries once a year. In our townhome the two bedrooms' detectors are wired together, so if one bedroom goes off so will the second bedroom's alarm. If it is still chirping you may need to replace the battery in the second bedroom's detector also. I'm not entirely sure that is the cause, but you should replace all the batteries if they are that old.

Call me if you would like help changing out those batteries..

Terry Parks

8885 Fraizer 

651-325-6756