Solar cell, which pin to connect?

#1

I want to connect a solar cell to a WiFi Lora 32 V2 Dev Board. Which pin do I have to use ?
Will I need to modify something on the board or add components before connecting to the board (resistors/diodes etc) ?
Is there a sketch available somewhere ?

Thanks in advance…

#2

WiFi Lora 32 V2 can’t use solar.
If you want use you can try connect it to the 5V Pin, but it may affect the 5V power supply.

If you want to use solar energy normally, You can do it like the picture below:
1.Cut off 1,2.
2.Connect the diode between 1, 2.
3.Connect the solar anode to 2.

image
image.png1268×633 49.4 KB

#3

Ah. Thanks for the answer.
I thought the board was advertised as solar capable elsewhere.
I think I will change my design to use the Cube Cell board, since my mechanical capabilities are not in the range to implement the solution you suggest. :wink:

#4

Is it possible to connect an LiFePo accumulator to the Board and (somehow) connect the solar panel to the 5V Input of the board? Maybe a 5 V voltage regulator chip

TS7805

in line?

#5

I went down the CubeCell path because of the lack of solar on the esp32 options and regret it. On paper the CubeCell is a nice board and the arduino core mostly works. But arduino libraries generally make assumptions that work on AVR, esp8266, esp32, and to a lesser extent stm32. Be ready for a lot of headaches getting libraries to work. And I was happier with lmic than with the heltec library for CubeCell.

My list of issues on CubeCell:

  1. Reset pin seems to source 50+ma defeating the ability of an external MCU to trigger a reset
  2. No ability to switch between LoRaWAN and LoRa on the fly
  3. Persisting join state requires disabling frame counters
  4. Three different SPI flash libraries won’t work, couldn’t find one that works
  5. Bootloader protocol is undocumented
  6. The watchdog reset period is too short.
  7. Lots of other random sensor libraries don’t work
  8. Only one hardware uart
  9. Maximum charge rate from a solar cell is 100ma
  10. Avrprog wouldn’t compile for cubecell
  11. Stuck with the heltec lora/lorawan libraries which don’t have robust support for saving network state

As I write this I am in the process of porting my app back over to a wireless stick light (esp32).

Get an external solar board. Heltec sells some. As do others. https://www.adafruit.com/product/4755 is rather nice. And heltec: please consider adding solar to one or more of your esp32 boards. From the post it looks like it might not be that hard.