ESP8266 Community Forum

- Sat Aug 19, 2017 5:22 pm #69295 Many thanks for your answers!

The INA3221 module looks very promising, having a single unit to monitor three channels. However, it looks like all boards available on-line have been wired so all three channels share the same power source. Or did I interpret that wrong? In my case, I need to monitor different power sources, so these boards do not seem useful.

The INA219 looks like a better option, even if I need a board for each channel (available boards can be configured to one of four I2C address). Most online vendors have a "blue" and a "purple" version, but I cannot find any difference between them, do you?

- Sat Aug 19, 2017 6:18 pm #69297

it looks like all boards available on-line have been wired so all three channels share the same power source.

I wasn't thrilled about that either, along with the thin traces. A few cuts with an Exacto knife, maybe a wire jumper or two, and it still could be used on multiple supplies as intended.

- Sun Aug 20, 2017 2:27 am #69317 They are not looking as independent channels at all and I have doubts about hight current measurement thru that tiny traces on board.
Actually, if you look at the used shunt resistors values (100mohm) and because the INA219 full-scale range for PGA/8 is 320mV you can see that the intended target is for a max 3A current measurement. Don't know anything about the quality of the shunt resistors (temp drift,etc) so cannot say how precise can be in time.
For multichannel solution I preffered to stack more than one SmartMon boards, keeping the RTC only on the "master" one.

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- Sun Aug 20, 2017 10:15 am #69326 I would buy IN219 boards and set them for different addresses. If you need higher than 3 amps then change the shunt resistor. IN219 boards can be bought for $1.50 usd each.