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?
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.