Remote Power Monitoring system AC or DC current measurements

Cloud IOT Hosting / Storage Options Looked at in initial exploration of subject:


Github for above project: – Desinged to be installed on local hardware like raspberry pi – is being maintained but does not seem to be highly used


ESP EASY Firmware – The firmware option I am using works with a variety of cloud data options like or local home automation software like


Thingspeak – The cloud data storage and reaction engine I am using – seems like the best current open source option – repository is here

Example beehive monitoring using Thingspeak and Arduino (CC3000 wifi module)

Embed thingspeak chart in wordpress post

Install thingspeak locally

Fancy Multi Value Charts

weather station with large chart output :

Example using thingspeak + arduino uno + esp8266


reading data from channel as text string:


getting started tutorial presentation


Isolated Voltage Monitoring

Voltage sense transformer testing results from Arduino Forum – and another page in that thread with example schematic of usage

ZMPT107 2mA/2mA ZMPT101B



DC shunt monitoring
– mainly for systems with existing shunts – current clamps are more convenient and practical for a new system.

INA219 I2C single channel digital current shunt monitor from TI

Adafruit makes a breakout board


INA3221 12C 3 Channel shunt amplifier product page from TI

$4.5 on Digikey

Switchdoc Labs has a breakout for $15

Arduino Library for INA3221


I2C Analog to Digital Converter 

ADS1115 I2C 16Bit 4 Channel (2 channel differential) ADC

Arduino library for additional software I2C

ESP8266 Analog Input

Using an external MUX IC to get extra channels


For 60V max input (48v battery system)

Divider = 68KOhm and 1Kohm for 60V max input Calculator


60V = 60V 🙂

44V = 44.2V 🙂


For 20V max input (12V battery system) Calculator

Divider = 22K and 1.3K resistor


12V = 12V

13.7V = 13.7V

AC Current Transformer

Calibration procedures from OpenEnergyMonitor



DC (or AC) hall effect current clamp options: 

YHDC HSTS21 Hall Split-core Current Sensor Input 600A Supply voltage 5V Blue

ADC to read these analog sensors with the ESP8266 which only has 1 analog input.

Adafruit breakout

Adafruit library




Hakalau System, actual inverters will be 3KW each for 21 KW max.

Outback FXR3048A 3KW 48V inverter max input current Continuous = 90A Peak = 150A


Humidty Sensor SI7021



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