Solar power an ESP8266-based plant moisture device?

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peejayw

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#325019 28-Jun-2026 08:34

I want to try to power a soil moisture device in my glasshouse. I already have a small 6v solar panel and some 18650 batteries so would something like this handle charging the batteries as well as supplying 5v to the device at the same time then switching to battery output when solar drops?

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.

boosacnoodle

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#3506748 28-Jun-2026 09:51

Not exactly what you are asking but I am using the Xiaomi Mi Flora Plant Sensor which does much of what you're asking (save for being solar powered).

peejayw

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#3506750 28-Jun-2026 09:56

Thanks for that. I have made my sensor following this guide, seems to work well using a power bank so far.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.

haydenw

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#3506766 28-Jun-2026 10:01

Seem to be getting a 404 on the link 🤔.

Some of the cheap power boards aren't very clever, so recommend one that manages the power like a MCP73871 based board would be good.

Depending on your cell configuration (parallel/series etc), you might need a boost converter to get your 5V.

Ge0rge

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#3506813 28-Jun-2026 10:11

I'd just use a CN3791 board. What you have linked to is probably a bit of overkill for what you're after.

Connect your 185650s in parallel to one battery plug, your soil moisture device to the other battery plug, and your solar panel to one of the solar plugs. The mppt boards come with a couple of leads that have the jst plugs on them - mind the polarity if you cut and join them, they are switched at opposing ends.

Edit - just read you need 5v out. The CN board will still work to charge your batteries but you will need to boost the 3.7v from the battery if you can't change it to run from 5v

elpenguino

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#3506857 28-Jun-2026 15:09

The way I see it, for a more slowly changing parameter like soil moisture, you are better off moving to zigbee from wifi.

Wifi chews power and from my tests, the ESP8266 isn't great at deep sleeping.

You will probably drop your power requirement by 90% moving to zigbee.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

richms

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#3506859 28-Jun-2026 15:57

For my meshtasic (soon to be meshcore) boards I got some solar string light solar panel boxes off AliExpress and just grabbed flower for the esp or nrf board from the cell directly.

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Ge0rge

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#3506877 28-Jun-2026 18:14

Have a look at this project. Basically explains how to get an esp32 to take tiny sips of power using wifi to measure a watertank level. Be very easy to modify to measure soil moisture.

peejayw

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#3506878 28-Jun-2026 18:17

Thanks for all the info everyone, lots there to consider.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.