Reply To: Case for Lower Threshold Voltage on Mayfly Stations

Jim fascinating, thanks for sharing and been re-reading your document a couple of times.

(I’m redoing my previous post as I got a bit excited with a power discussion).

I use a higher threshold V for transmitting cellular information. The voltage is dependent on the battery type/capacity and the load on the battery.
I use 3.8V as a threshold to stop transmitting,.

Under 3.8V I’m reserving the power to purely take readings, and extend the length of time that readings can be taken. Objective is at least two weeks.
On a transmission attempt, if the Voltage is above 3.8V then it transmits all the outstanding readings taken under 3.8V.

See this test that shows this.

So a question, from your document, how are you measuring the LiIon battery voltage?

I don’t have good results from using the Mayfly’s mega1284 Vbat.

I put some data out and never got a response https://www.envirodiy.org/topic/battery-measurement-accuracy/

I implemented a separate monitor on ADS115 AA0  https://github.com/neilh10/ModularSensors/wiki/Hw-Mayfly-ECO-R04

The results can be seen on the two Battery Voltage measurements on https://monitormywatershed.org/sites/TUCA-Na13/

For maintenance the “EnviroDIY_Mayfly Data Logger”/”V, solar or LiIon Batt 5-3.5V” indicates there is a good solar aspect charging the Adafruit 4Ahr battery.

The AA0 sensor “All_External Voltage Divider”/”LiIon battery V” indicates how well that solar aspect is charging the battery.