I've created a TH02 daughter board for the Moteino and have two running for 2 years on a single charge to a 2000mAh LIPO. The Moteino is a stock R4 with a RFM69 433Mhz transceiver; I've dialed down the radio to use a lower baud. These have been transmitting temperature, humidity, dewpoint, and volts in one minute intervals during the 2 years. I'm using the LowPower library, using a spare pin to power the TH02 and using digitalWrite HIGH/LOW to turn it on/off.
Using a simple multimeter to measure the volts of the battery:
1/15/17 4.19v --> 1/14/19 3.64v readVcc() reports 3.24v
1/14/17 4.18v --> 1/14/19 3.65v readVcc() reports 3.26v
It is odd that the Moteinos report different volts via the standard readVcc() and it's been this way the whole time. Not sure why there would be a 0.02v difference???