Battery value discrepancy

I notice that when reading the battery value in the Ruuvi app and comparing it to the actual battery value using a DMM the values are quite different. There have been a couple of related posts but there has been no solution listed in these posts.

Using the ruuvi app the reported values are 2.886 (actual DMM measured value 3.037) , 2.777 (actual DMM measured value 3.030) , 2.616 (actual DMM measured value 3.022) and 3.016 (actual DMM measured value 3.126). Why such a discrepancy?

iPhone 13 Pro latest firmware
Ruuvi App latest firmware
ruuvi versions 3.30.4 + default
3.31.2-RC1 + default
3.31.1

Hello,

The DMM measures long-time average voltage which does not represent the battery voltage under radio activity load.

Long explanation is here: https://ruuvi.com/ruuvi-firmware-part-13-battery-measurement-synchronized-to-radio/

TLDR:


Your DMM misses the battery voltage droop caused radio activity while RuuviTag measures the voltage right after load to get more accurate estimate of how battery is doing. That causes RuuviTag to report lower voltage than DMMs.

1 Like

@otso thank you for the reply and explanation

this is really good information for me, thank you for sharing with us