They are going crazy off and on with the power off

Besides replacing all the 9 volt batteries...

What else should I do or look for

Take em down and pull all batteries. To much steam or fireplace smoke in the air.

I had a couple of the electric powered ones that would always seem to have an issue in the middle of the night. Got tired of it and ripped them all out and replaced them with battery powered ones. No more false alarms at 3AM.

Could very well be this. A lot of folks will boil big pots of water to help heat the house, then their smoke detectors start going off. Smoke detectors DO NOT like steam.

Lefty do you have thermal detectors as well? I have both smoke and thermals, my thermals have been going off since I'm running an open oven and space heaters.

Take them down and blow them out, if on an electric circuit reset the breaker.

^^^^^ This. Mine were doing it last night and I called the company. Use some computer canned gas or a hairdryer on cool. Sensors have dust on them and are shorting out. If yours are hard wired there is one that is setting them off. Locate that one, find your breaker and cut the power then unplug the one causing the problem.

Mine are going off each time the power goes off which is about every hour.

I pulled them all down around 4 am this morning, it gold really old

Thanks for all the responses guys

I really appreciate this and the texts also.

First one I pulled down was the problem.

I’m hoping it was just the battery, waiting on the power to come back on....

How old are they? Mine were getting flaky; did some reading and the detector sensors have a 10 year life. Replaced them all, problem solved.