ESP8266 solar powered, will I burn my house?

HI guys,
I want some advice before making something stupid :smiley:

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?

The diode is backwards in the drawing.

The major concern is whether the 18650 battery could be overcharged and catch fire, but the charger should help and the panel current is probably too low to worry about.

Don't waste your time with Fritzing diagrams. They are usually misleading, often wrong and rarely very useful. Hand drawings are preferred.

"ESP8266 solar powered, will I burn my house?"

If you have to ask, then Magic 8 Ball says a definite "possibly".

jremington:
The diode is backwards in the drawing.

The major concern is whether the 18650 battery could be overcharged and catch fire, but the charger should help and the panel current is probably too low to worry about.

Don't waste your time with Fritzing diagrams. They are usually misleading, often wrong and rarely very useful. Hand drawings are preferred.

Ok thanks for the answer, I really appreciate.
I correctly connected the diode as per your suggestion.
The TP4056 should have an overcharge and over discharge protection.
so do you consider it pretty safe?

is there some experience on the forum with the TP4056? is it ok in protecting the battery from overcharge and discharge?
is the MT3608 step up module ok?

No one can protect you from your mistakes but yourself.

If you want to be safe, build the circuit and test it carefully, over a period of time.

Check the battery temperature and voltage during full sun. If the battery never gets warm and the voltage doesn't exceed about 4.2V, you will probably be OK.

jremington:
No one can protect you from your mistakes but yourself.

If you want to be safe, build the circuit and test it carefully, over a period of time.

Check the battery temperature and voltage during full sun. If the battery never gets warm and the voltage doesn't exceed about 4.2V, you will probably be OK.

on the internet I see that someone compaints about the fact that the TP4056 isn't able to safely charge a 18650 while the load is connected to it.
is this true? is this a problem of the old TP4056 module that has only one output?
now the new TP4056 have an output for the battery and one output for the load.

is it safe to use that module for both the load and the battery charge at the same time?

Read the TP4056 data sheet very carefully to determine how to use it properly, and to learn what claims the manufacturer makes about it.

Hey! You dont need that MT3608 DC-DC Step Up Module for the Wemos.

Here is why: The Wemos runs on 3.3V logic. The TP4056 supplies somewhere around 4 Volts.

If you supply these 4 Volts to the 5 Volt input on the Wemos it will be converted to 3.3V eventhough it`s just 4 Volts.

Here you find the datasheet of the ME6211 powerregulator of the Wemos:

on page 12 you find the relevant diagram on the bottom of the page

Hope this helped

I been using a TP4056 to keep a 18650 battery charged from a solar cell since the 11th of Feb 2020. No problem.

I use a 12V solar panel, I was lucky to get 5V out of the 5V solar cell. Mostly I got an average of 4.2 volts from the 5V solar cell, makes an issue charging a battery to 4.7 volts, from a 5V cell. I run the 12V output from the solar cell to a step down to 6V switching regulator. The switching regulator output goes to a TP4056. The output of the TP4056 goes to a low drop out 3.3V regulator. The low drop out regulator powers a BME680 and a ESP32. The low drop out regulator has the proper input output caps.

The ESP32 deep sleeps for 1 minute, wakes, reads the BME680, publishes the data to a MQTT Broker, and goes back to deep sleep, runs 24/7.

If you insist on using a diode before the TP4056 you are losing precious voltage to charge the battery.

The BME 280 and the other external components will be drawing power 100% of the time. I did concoct a scheme to build circuity to remove power from the BME680 when the ESP32 was asleep but found the circuitry was not needed and messed with the accuracy of the BME680. In your case you might consider shutting off power to the extra components when the micro-controller is asleep.


Will it burn your house? I cannot answer that question, I'm not interested in being libel/responsible for any error you may make.

m_schlachter:
Hey! You dont need that MT3608 DC-DC Step Up Module for the Wemos.

Here is why: The Wemos runs on 3.3V logic. The TP4056 supplies somewhere around 4 Volts.

If you supply these 4 Volts to the 5 Volt input on the Wemos it will be converted to 3.3V eventhough it`s just 4 Volts.

Here you find the datasheet of the ME6211 powerregulator of the Wemos:

https://datasheet.lcsc.com/szlcsc/Nanjing-Micro-One-Elec-ME6211C33M5G-N_C82942.pdf

on page 12 you find the relevant diagram on the bottom of the page

Hope this helped

don't agree with this, as soon as the pump starts, voltage battery drop and the ESP crash without the MTP3608 module.