Estimator · runs in your browser
How long until you are up a ladder again
Battery life is decided by how often the thing talks, not by how good the battery is. Change the reporting interval and watch the months move.
What actually drains it
It depends on how often it talks, and the answer surprises people. A sensor reporting once an hour spends most of its life asleep, and that trickle — ten or twenty microamps, around the clock — is where the battery goes. Halving the reporting interval barely moves it.
Report every minute and it flips. Now the radio dominates, retries hurt, and the interval becomes the only thing that matters. The calculator tells you which side you are on.
And retries cost more than they look. A device at the edge of the mesh sends, waits, gets no acknowledgement and sends again. Each attempt costs the same as a successful one — which is why a repeater often does more for battery life than any setting.
Questions people ask
Why did my sensor die in three months?
Almost always a short reporting interval, a weak mesh (retries cost far more than a successful send), or cold. Cold is brutal on coin cells.
Do CR2032 and AA differ that much?
Enormously. A CR2032 holds around 225 mAh; two AA cells hold roughly ten times that. Same sensor, wildly different life.
Is this exact?
No, and no estimate can be. It is a model: use it to compare settings, not to plan your calendar.