we have several AMZN Blink motion-sensing cameras. 3 of them are mounted outdoors (WA state). Blink recommends using lithium AA batteries for power, and they claim 2 year battery life. I think all three are still running, as well as the indoor cameras, and this is well beyond the 2-year guesstimate for battery life. Battery life would depend on how often the cameras are accessed, and ours are not always armed, but they're always on. I wouldn't put ordinary alkaline AA batteries in these units based on the battery life, and more importantly that these batteries live to leak all over your electronic gear.
--rick chinn
near Seattle
