RAK Repeater Mini - not charging?

WisBlock
1

Just set up and testing a Repeater Mini. Charged charged battery to ‘full’ via USB. Battery level said 97% 4.15V. The node has been outside in full sunny days for 48 hours. The battery level via Meshtastic metrics (phone app) now shows 92% 4.08V but the metric graph has displayed a gradual battery charge level drop but no increase in battery level via solar charging.

When does the solar charging kick in? Is there a certain battery level/battery voltage where solar charging starts?

To test the panel, I disconnected the battery and in full sun the solar panel powered the unit. At night the battery is providing power.

Running factory flashed Meshtastic FW 2.5.20.4c97351. Meshtastic Client role.

I do not have equipment to test voltages etc. Just relying on Meshtastic data. Any help appreciated.

2

Welcome to the forum @MJV

The battery is not constantly charged. The charger chip is applying a charging algorithm.

This is my Repeater Mini over two days. Yellow is the battery voltage, Blue is the sun exposure (measured with a pyranometer).

image

Just check the battery voltage over a week. If you have enough sun, you should see a similar curve.

3

Thank you for your response. Much appreciated. I will watch it over the coming days.
Your graph implies that 3.88v is around the point charging starts, is that a typical level to expect?

4

No, in the graph the charging starts when the sun comes up, see the blue line going up when the charging starts.

5

Sorry, I was trying to establish a battery level point/threshold when the algorithm triggers charging.

6

This is from the data sheet of the charger:

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Start charging is ~4.1V

Keep in mind that the voltage reported by Meshtastic is not exactly the real battery voltage. It is read by an analog input through a resistor network, so a lot of tolerances are influencing the reading.

7

Thanks so much for your responses