Using the Qwiic Openlog to monitor a battery

I am looking for something that I could use to monitor my Aercus Weathestation’s Battery. I have an outdoor weather station that normally uses non rechargeable 3xAAA lithium batteries (4.5V total) with a solar panel that has failed.

The solar panel used to supply power during the day and the batteries supply power at night.

The solar panel has failed and the unit was chewing up expensive Lithium batteries. The Weatherstation is mounted some 3->4m off the ground so I mounted and external battery box which contains 4 x 1.2V 1900mAh Eneloop batteries (4.8V total). I am almost 70 so climbing ladders is not good!

The batteries are mounted in a weatherproof grey box.

I have a good supply of these batteries as I use them in my photography for my Flash Remotes and Flashes.

My weather station operates on 433Ghz and sends data to an indoor unit (observerIP). I can access this unit with a web browser and it does tell me when the battery level goes to LOW STATUS.

However I wanted to be able to see if I could somehow monitor the actually battery supply and quantify the discharge.

Currently I am doing manual measurements every couple of days. Workable and inexpensive but I would like to learn more about using today’s technology so thought of doing a project on it.

My objective is to be able to monitor this power box with a few goals in mind.

  1. Determine the average time to LOW STATUS
  2. Determine the Voltage when Low Status occurs

I saw the Qwiic Openlog on the wb site and in it’s description it said

write some simple code:
myLog.print(“The battery voltage is:”); myLog.print(batteryVoltage);

*And your data will be recorded to LOG00001.TXT on the microSD card for later review. The Qwiic OpenLog can store or “log” huge amounts of serial data and act as a black box of sorts to store all the data that your project generates, for scientific or debugging purposes.*

I am new to this field and have no idea of how to go about this.  I have tried looking around at various places but I don't really know what I am looking for so wondered if you could point me in the right direction on

1. How to use this device? 
2. Any other bits that might go with it to achieve my goals

3. Do you have a kit with instructions that will do what I want to achieve?
The idea of just a log file is all I need at the moment but maybe expand my knowledge later on to see if I could use as Raspberry Pi zero (I already have one of them that I bought off you guys) to send files to me?

I hope you can help me with my project.  
I am a pensioner and want to try mentally active and keep myself busy!
Most grateful for any assistance.


Hi Ron!

Here is a tutorial to check out that might help get you started:

Or you could make a wireless one that connects to your wifi like this project:

Let me know if you have any questions!