ESP8266 Community Forum

- Fri Mar 27, 2020 5:58 pm #86216 HI guys,
I want some advice before making something stupid

I want to create a simple solar watering system with a small water pump.

Basically I will have those components, please tell me if it will work without burning my house.




As you can see from the image I have two 5V solar panels in parallel
connected to the TP4056 battery charger with a 1N4001 diode to avoid back current.

The battery is connected to the TP4056 charger and to the MT3608 DC-DC Step Up Module.
The MT3608 DC-DC Step Up Module powers the ESP8266 microcontroller via VIN directly.

To the ESP microcontroller I attached a relay shield that will drive the water pump, the water pump is directly connected to the 18650 lithium battery.
I attached a BME280 temp sensor to the ESP.


I will use deep sleep on the ESP8266 and it will be turned on every 10 minutes to send temperatures via MQTT. Once a day it will power the pump for about 15 seconds to give some water to a plant.

Does this have sense? Can it work? Do you see some problems?

- Sat Mar 28, 2020 4:44 am #86220 Couple of things:
Your solar panels will go above 5V on a sunny day and my charger is similar to yours and the max input is 5v. It might be OK but you never know. I suppose you could try putting 6V though it and see if it is OK before you assemble it.

Does your BME28o have a voltage converter onboard as the standard voltage for a BME280 is 1.7-3.6V

You have a ground and live wire going to the same rail for the BME280.

The attachment is to small to see the pin information.

- Sat Mar 28, 2020 8:58 am #86222

Couple of things:
Your solar panels will go above 5V on a sunny day and my charger is similar to yours and the max input is 5v. It might be OK but you never know. I suppose you could try putting 6V though it and see if it is OK before you assemble it.

Does your BME28o have a voltage converter onboard as the standard voltage for a BME280 is 1.7-3.6V

You have a ground and live wire going to the same rail for the BME280.

The attachment is to small to see the pin information.

thanks for the kind answer and for the time in reading the picture.
this is a bigger one.


if you click this link it will open an image you can zoom
https://i.postimg.cc/CSw-KCz32/Solar-Station-bb.png

I corrected the BME ground as per your suggestion

Regarding the solar panel that can goes up to 5V, isn't the 1N4001 supposed to lower the maximum voltage from the panels to a "good level" for the TP4056?

PS: I added a divider resistance connected to the analog input of the ESP to check for the battery level

Thanks.

- Sat Mar 28, 2020 10:12 am #86223 The diode is to prevent the charger "charging" the solar panel if there is a problem. It is also the wrong way around - the band is on the direction of current flow.

I have a greenhouse monitor which is similar: viewtopic.php?f=11&t=19458 I have a LDO Linier regulator between the solar panel and charger. But it was my first project and I should have gone for a higher voltage output panel but I did not realise the panels went above 5V so put it in as a safety. Of course it does not work when the panel is only putting out 5v! I was going to buy a higher voltage panel but might be able to wok around it with a Mofset. I intend on revamping it this year when I get a home soldering setup.