What is it?

An ESPhome node which contains 2 INA226 voltage and current monitors, 2 Form A (SPST) sets of relay contacts, and 2 NTC thermistor inputs.

Why did you make it?

To monitor an off grid DC power and UPS system. I needed to monitor the battery, and the AC backup power supply currents from homeassistant.

What makes it special?

This is a complete, packaged DC voltage and current monitoring solution for ESPHome. It is completely assembled except for 2 tact switches which need to be soldered in by the user. (See below for the reason why)

Features

• ESP32 Microcontroller
• Provides 2 current/voltage monitoring channels using the Texas Instruments INA226 voltage and current monitoring chip.
• High side or low side current monitoring.
• Bidirectional current monitoring (charge/discharge).
• Provides 2 sets of normally open (Form A) dry relay contacts rated for 2 amps and 30 volts DC.
• Provides 2 NTC thermistor inputs (3 pin JST XH connector).
• TVS diode protection on the power supply input, ESD diodes on the voltage sense and current sense inputs.
• Din Rail ABS Plastic Enclosure and graphic overlay sticker.
• 12 pin Pluggable Terminal Block for Power, Voltage Sense, Current Sense, and Relay Contact Connections.
• Runs off of 10.8 to 30VDC supplied by an external power source.

Hardware included in the kit

* 1 ea. Main PCB.
* 1 ea. ABS plastic enclosure, graphic overlay sticker and 4 retaining screws.
* 1 ea. mating 12 pin screw terminal pluggable power connector.
* 2 ea. 6mm Tact switches to be soldered in to EN and BOOT footprints the board.
* 2 ea. 3 pin JST connector and pigtail.

Not supplied in the kit

* 3.3V serial adapter for flashing firmware onto the board and connecting cable.
* DC power source.
* Wire.
* Wood screws for attaching the controller to a backboard.
* Current Shunts/Sensing resistors.

Some Soldering Required

Because FCC certification is too expensive to undertake for a low volume device such as this, the product is shipped as a tested kit where the EN and BOOT pushbutton switches are supplied but not soldered onto the board. In order to program the device with your customized ESPHOME firmware, the EN and BOOT switches will need to be soldered to the board so that the ESP32 can be placed in upload mode.