BTW Why do smoke alarm batteries die at night? Because temperature drops and a weak battery's voltage output drops with temperature.
BTW Why do smoke alarm batteries die at night? Because temperature drops and a weak battery's voltage output drops with temperature.
"6 AA Energizer Ultimate Lithium batteries Long-life batteries designed for multi-year operation"
and for the wired version:
"3 AA Energizer Ultimate Lithium backup batteries Long-life backup batteries designed for multi-year operation"
I suppose it depends how much you use its features like lighting-up your hallway, but that's more-than reasonable in my opinion.
For example with a wireless energy transmitter (it doesn't need to be too powerful).
Or "solar powered" with a good set of (rechargeable) batteries.
Maybe they are in league with battery manufacturers, but I feel safer, and have plenty of extra mostly-charged batteries for remotes and video game controllers!
[1] http://www.wired.com/business/2013/10/nest-smoke-detector/al...
Looks like a couple of years with 6 AA batteries.