HiLetgo 5pcs Voltage Detection Module DC 0~25V Voltage Sensor for Arduino

Precision 1% or better

As long as you setup the wiring correctly, you should not have any issues.As a suggestion for calibration involving Arduino code, here is what I did:float SensorOutVolts = 0.0; // Sensor Output Voltagefloat rOhm1 = 30000.0; // Resistor 1 Valuefloat rOhm2 = 7500.0; // Resistor 2 Valuefloat baseVoltage = 5.12; // Arduino Base Voltage//Read Solar Array Voltagevoid ReadVoltage(){// Read the voltage on the pina1PinVolts = analogRead(A0);//Calculate the input voltage to the dividerSensorOutVolts = (a1PinVolts * baseVoltage) / 1024.0;// Calculate the input voltagedata.SystemVoltage = SensorOutVolts * (rOhm1 + rOhm2) / rOhm2;The value 'baseVoltage' in many code examples is set to 5.0. This value can be changed to whatever yours is getting. It will vary from one application to another because not everyone is using the exact same power source. Measure yours with a digital voltmeter and change it accordingly.

This product is not special, but just a simple 2 resistor voltage divider using 1% resistors to reduce the voltage by 5 to 1. And for the price is works very well as designed to.

Good enough.

Works fine for my project, I am reading fairly accurate readings from 0-25v DC. Basically, it just does a voltage divider for you, but this is just more convenient than building a much of voltage divider circuits.

Nice small size with flexible specifications.

How do we power an esp8266 microprocessor with the battery while also checking the voltage with the voltage sensor? As soon as I unplug the USB cable, there is no power to the esp8266 anymore. I tried plugging a jumper wire onto the + pin and the other end to the 3V3 pin on the 8266, but that doesn't give it power. I also tried connecting the jumper wire to the 5V pin on the 8266, but still no power. If I connect the battery's wires directly to the 3V3 pin via a breadboard, my 8266 works fine. Anybody have any ideas? Is there any documentation for this Voltage Sensor board?

Works as advertised. Easy hookup.