esp32 based weather station, mqtt
- temp, humidity and pressure from bme280 module
- rain sensor by a reed contact which resets the module
during connect and mqtt send the esp takes around 100mA during 5 seconds. In deep sleep the AZ delivery module takes 1.5 mA (maybe due to the always-on power led).
If I wake up every 10 minutes and send data, it will consume 6*5s*100mA = 3000mAs within 1 hour. Addionally the 1.5mA*(3600s-6*5s) = 5355 mAs. Together I get 8355mAs consumed, or 2.3mAh. in other words, within 24h I consume 55mAh.
I will be using a small 3W solar panel. This gives around 20mA*8h = 160mAh under weakest conditions (200mA in full sunshine). This means that I still have 160mAh - 55mAh = 105mAh left each day to make sure that the battery is really charged. I tmeans I should have enough power even in winter to operate the esp32 24/7.
Note my battery has 800mAh, so enough buffer to cover the "dark" times of the day.
here are somoe measurements. The good news is, that approximately all consumed energy is renewed during daylight time. We had 3 very cloudy days. The peak at the end of the graph is a sunny morning with full sunlight on the solar panel.
What surprises me nevertheless: First day, I had 1 minute interval to connect to WLAN and post data, later on 10 minutes. From the graph, this does not seem to make any difference in power consumption.
I have meausred again, and it reveals:
- the Waveshare charger consumes ~2mA all the time
- the AZ Delivery ESP32 board consumes 2mA in deepsleep.
- the actual sending might be faster than 5 seconds.
During the winter months it showed that sun the battery was not charged envough. I made two modifications:
- changed the board to a board with low power consumption in deepsleep.
- removed all leds from the Waveshare battery charger board (there were 5 leds on all time)
mosquitto_sub -h -t wetter2/rain2