The power supply of the SensorHub by an RAK9154 solar battery enables the autonomous operation of the complete measuring station. I describe this in my eBook SensorHub IoT Applications.

I had to close the chapter describing this application as follows: On sunny days, recharging the battery will hardly be a problem. On cloudy days, this balance looks less favorable, and it remains to be seen whether the weather conditions in my area offer sufficiently good conditions. It is, therefore, essential that the anticipated variant of the SensorHub promises to reduce power requirements further.

I have good news today. I got a new version of SensorHub and replaced the existing one. As you can see in the screenshot of the WisToolBox app, the hardware version changed from VF zu VH and the firmware from V1.1.79 to V1.2.6.

The following screenshot shows the behavior of the solar battery before and after the SensorHub replacement. The weather conditions are worse over the whole period.

You can see that before the replacement of the SensorHub the current consumption was about 50 mA in the phase of discharge. After the replacement, it is reduced significantly. The same behavior can be seen in the battery capacity curve. Before the replacement, the battery capacity dropped between 10% and 20% per day without recharging.

After the replacement, the discharge remains quite small. The current consumption was about 10 mA in the phase of discharge, and the battery capacity dropped by about 1%. The weather conditions were very bad therefore, the recharging was limited to a short time.

Now, I’m waiting for a sunny day so that the solar cell can charge the battery sufficiently to survive a period of bad weather without losing the connection.

The sun came out for a few hours, and the battery was charged. During this time, the solar cell delivers a considerable charging current.

We are on the right way, as you can see, after two days with a bit of sun.

---

2023-11-23/CK