Impact of Reporting Interval and decimals on battery life

[Oliver_S]

Hi,

I have two different questions.

Last year, I bought a Homey Pro and a bunch of Sonoff temperature sensors, SNZB-02P. Recently, I bought another 5 sensors of the same model. By the way, I think they’re really good sensors.

Something strange I noticed with the new sensors is that they default to 0 decimal precision for Humidity reporting (57%, 58%) while the older sensors defaulted to 1 decimal place (57.1%, 57.2%).

My first question is - does anyone know why that would be? Is it possible that Homey sets the reporting precision during initial pairing, and the default has been changed? Or perhaps on the Sonoff side there’s a different default despite being the same model of sensor?

My second question - what is the impact on the battery life of the sensors for this as well as the ‘Reporting Interval’ config option?

Naively, I’d expect that increasing the reporting Interval should linearly decrease the battery usage - so for example going from 30s reporting to 90s reporting should roughly triple the battery life. Is that actually the case?

I’m less sure what the impact of changing the ‘decimal’ for either the temperature or humidity of the sensor would do. In the Homey UI, the sensor appears to only send a message if the reading changes by the decimal threshold (so for example I noticed the humidity reading can be ~an hour old because the humidity does not change by a full % point that often) but looking in ‘Homey Developer Tools’, the ‘last seen’ values don’t seem to line up with this. So are these values at all relevant with respect to battery life?

I’d appreciate any insight!

(One final thing - is there any way to update these settings for all my sensors in bulk rather than one by one?)

Thanks,

Oliver.

[Peter_Kawa]

@Oliver_S

Something strange I noticed with the new sensors is that they default to 0 decimal precision for Humidity reporting (57%, 58%) while the older sensors defaulted to 1 decimal place (57.1%, 57.2%).

@Oliver_S

Or perhaps on the Sonoff side there’s a different default despite being the same model of sensor?

This.
Sometimes what seems to be the same model has a slightly different functionality because of other firmware.
It’s very well possible the “older” sensors’ humidity values also default to integers after a firmware update.

@Oliver_S

Naively, I’d expect that increasing the reporting Interval should linearly decrease the battery usage - so for example going from 30s reporting to 90s reporting should roughly triple the battery life. Is that actually the case?

Not in a linear way. Sensors send/receive other data as well.
So, increasing intervals saves battery life, but only to some extend.

@Oliver_S

Homey UI, the sensor appears to only send a message if the reading changes by the decimal threshold

Also to save battery life, sensors only send values when they’ve changed by a minimum amount, probably like 1% steps for humidity.

If the sensor supports it, app developers can decide to add a setting to in-/decrease the step size.
I’ve no clue if Homey firmware can overrule such stuff.

@Oliver_S

One final thing - is there any way to update these settings for all my sensors in bulk rather than one by one?

Not that I know of.