Comments on: Power ESP32/ESP8266 with Solar Panels (includes battery level monitoring)

By: Sara Santos

Sara Santos — Mon, 30 Mar 2026 11:02:07 +0000

In reply to OktO.

Hi.
Thanks for your comment.
But, that only applies to some ESP8266 models.
Regards,
Sara

By: OktO

OktO — Mon, 30 Mar 2026 09:53:19 +0000

careful with the ADC, it is expecting 0.0V-1.0V (outputs 0-1024). So don’t feed it with 3.3V directly on the ADC pin unless you have a devel board with voltage divider on board. You need to have a voltage divider which outputs at 4.2V = 1.0V
+4.2V—-R1(320k)—o(ADC)o—-R2(100k)—-| GND (unverfied, but something like this)

By: webkonto

webkonto — Fri, 12 Sep 2025 17:19:33 +0000

Just a question: in theory, this should not work because the charger will never end charging. It should end charging, when I_change is very low (e.g. 0,01A). If your ESP needs more than this (and it will use between 0,25 and 0,01A with my esp32c3 Mini), charging never stops. I tried it here with a similar setup and the charger never stopped.
if so, this gets tricky now. You need to switch two stated: “Battery is charging” and “Battery is not charging” or you ignore all this and use a protection module between charger and battery (so infinite charging should not damage the battery) and get an “dirty circuit” award on top….

By: rafa

rafa — Wed, 16 Jul 2025 22:42:08 +0000

In reply to karen zabala. cual es el caso de monitorear??

By: Sara Santos

Sara Santos — Thu, 10 Jul 2025 09:45:31 +0000

In reply to Sreekar.

Hi.
You need to disconnect the battery from the ESP32 if you want to connect it via USB to your computer.
Otherwise, it will damage your board.

Regards,
Sara

By: Sreekar

Sreekar — Wed, 09 Jul 2025 16:41:07 +0000

While using the solar panel to charge, simultaneously if i connect the esp32 with cable to upload new code or monitor the values in serial monitor, will the circuit resist it and be safe. Or will it damage my battery?.

By: Yusri

Yusri — Sun, 18 May 2025 14:23:43 +0000

I found that once battery cut off due to low voltage and then fully charged, ESP32 was not working. Why?

By: Sara Santos

Sara Santos — Wed, 12 Feb 2025 10:13:07 +0000

In reply to Lior.

Yes as long as you’re not using another power source on the USB.
regards,
Sara

By: Lior

Lior — Sun, 09 Feb 2025 12:23:07 +0000

Hi,
I read that it’s not recommended to supply voltage to the 3V pin.
I see that you provided power to this pin— is it safe?

By: zygfryd

zygfryd — Fri, 08 Nov 2024 16:02:57 +0000

In reply to Ed.schmidt.

majority are 3.3V
but, if you want 5V then I would go different way:
1- the same logic but depending on what is the device you can use:
– mosfet or
– relay
to turn them on
2- check online how to control mosfet (N-Channel) or Relay – you can use the logic from what I explained in the above post – just instead of direct power from GPIO to the device, you use the GPIO to control the mosfet or relay
3- since relay takes time (ms) you might implement some delay (i.e. 100ms) once you power it on
4- before going to sleep switch GPIO to LOW to make sure mosfet or relay are off