Hello everyone,
many thanks in advance for the help.
The basics of the project and the formulation of objectives:
The temperature in a greenhouse should be accessible via the Internet and the Thinkspeak platform.
Problem:
There is no power supply or internet available on site.
Description:
To solve the problem of no electricity, it uses 18650 batteries to be recharged via solar panel.
A SIM900 module is used to transmit the data obtained to Thinkspeak.
An AHT21 sensor is used to record the temperature.
An Arduino Nano (China Clone) takes over the control.
In order to save power, the entire circuit should only be on at certain intervals. A TPL5110 is used for this.
The code for the Arduino is there, tested and working,
so the problem lies in the hardware area.
Parts used:
Batteries 18650 (2x)
TPL5110
mppt cn3722/cn3767
BMS
Solar panel
AHT21
Buck converter
Unfortunately I don't know how to make a circuit sketch, so a description of the circuit follows:
The solar panel is connected to the MPPT, which is connected to the BMS. Two 18650 (series) are connected to the BMS. The batteries occupy the 0 V, 4.2 V and 8.4 V connections. The voltages match.
A buck converter is connected to the BMS, which should bring the voltage to a fixed 5V.
The Arduino and the SIM900 are connected from this.
If a classic power supply is chosen instead of batteries, everything works well and the temperature is recorded and sent to Thinkspeak.
The problem is the power supply. Different voltages come from the BMS, which are usually not sufficient to operate the Arduino and the SIM900.
I read somewhere that the BMT need a charging current to "start". Is that right?
Is the BMS unsuitable for the application or where is the error in the project?
