ESP32 solar power advice

Hello. I am very new to electronics so please forgive me. I have an Arduino Uno and can make an led blink, but it is time to move on. I read about the ESP32 being able to use wi-fi so as a php developer I just have to send something to a database. I like the idea of weather data to begin with so I have spent most of today going in circles reading about how to hook one up to a solar panel.

The Thing Plus board looked good, but removing LEDs and such to get the deep sleep power consumption to a reasonable amount looked fiddly. So now I am looking at the firebeetle board, but when I saw on Google images someone with a solar panel in their schematic for this board on a weather station, they ran the solar panel and the battery through a lipo solar charger board then on to the ESP32. I thought the board was able to take input through VCC for a solar panel, or would that just power the board rather than keep the battery topped up?

I thought it wise to understand how it works before buying the wrong parts. Many thanks for any advice.

I run 2 ESP32's on solar.

The solar cells are 12V loaded, 17-ish V unloaded.

I use a 12V 8Ah LifePo4 battery.

I use a PWM charge controller.

The solar cells are wired in parallel and connected to the PWM charge controller.

The charge controller is connected to the battery.

The battery supplies a 5V switching regulator to power the MCU and circuits.


There is not a good Li solar solution.

I did, for a while, use a TP4056 to charge the battery and power the system. Nothing about the setup is hands off. A few times a year the Li battery will need replacing.

Thank you.

Sad to hear keeping a project like a weather station running independently with a small solar panel still isn’t possible. You’d think humans would have figured out how to keep a lithium battery alive for a year by now.

iamjulian:
Thank you.

Sad to hear keeping a project like a weather station running independently with a small solar panel still isn't possible. You'd think humans would have figured out how to keep a lithium battery alive for a year by now.

You've got a solution to be found that will make you a bundle!

iamjulian:
You'd think humans would have figured out how to keep a lithium battery alive for a year by now.

Well they have.

One approach is to sacrifice a bit of capacity from the Lithium battery and charge them with a voltage cutoff charger set to circa 3.9V, making sure that the charge current is also limited to a safe value.

You also need to make sure you dont let the Lithium battery go much below 3.3V.

How long does it take for solar energy to be converted into batteries?

Depends on many factors.

Typically, it takes about 3 hours of good sunlight to recharge the 12V 16Ah LiFePo4 battery used in my weather station project.

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