- The Soshine 6W solar panel available from Amazon is a good choice. It works well and provides enough power to keep a Meshtastic node charged up. But, there are some gotchas that we discovered.
- If you intend to use the USB output of this panel directly, we found that the USB regulation circuit is noisy and will interfere with your radio, especially in partial sun. You have to do one of three things: (1) Use a separate MPPT charge controller, (2) Use a capacitor to filter the output, or (3) Use the 5521 connector instead of the USB output. BE AWARE that you may need a Schottky 1N5817 diode on this output, depending on your charging method.
- And we also found that if you use this panel with a RAK Wisblock and intend to use the onboard charge controller, it’s anemic. It doesn’t use the full power output of the panel – It’s limited to 350mA. So I added a separate MPPT charge controller and directly charge the battery with that. This is the Waveshare MPPT board from Amazon, which is a good choice. Tested and working. Doing the calculations, if you use the onboard controller, average 4 full sun hours in a day, you net 7.7Wh of power. If you use the Waveshare external MPPT charge controller, you net 24Wh of power. You’re throwing away 67% of your power! Worth the extra $20 for the upgrade.
