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absalom-muc / MHI-AC-Ctrl

Reads and writes data (e.g. power, mode, fan status etc.) from/to a Mitsubishi Heavy Industries (MHI) air conditioner (AC) via SPI controlled by MQTT
MIT License
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Get Power usage #131

Closed HpNoTiQ56 closed 1 year ago

HpNoTiQ56 commented 1 year ago

Hi, I'm trying to monitor power usage (W,KWh or A) but the only value I could gather is TD and CT in A.

First, are TD and CT intensities in A? I've monitored them but TD is about 45 thus can't be in A and CT is too low I think!

Could you tell me if it could be done?

thanks,

dennistd4 commented 1 year ago

The CT value is the right one. Multiply it with your actual voltage and you will have the power in watts. Here it is slightly higher (about 10-40 watt) than the power measured by a Shelly EM, but maybe it's because of the length of the power cable (I use the voltage measured by the Shelly for the calculation).

buennerbernd commented 1 year ago

I‘m using CT * 230 to calculate the current electrical power. If my devices are off, this jumps between 0 and 62W. During heating I have peaks up to 1600W but normal are 500 - 900W. For power consumption in kWh I‘m calculating the integral over the time and get reasonable results.

absalom-muc commented 1 year ago

btw: In the documentaion and in the source code the TD unit is wrong, TD is the Discharge Pipe Temperature [°C]

@buennerbernd: strange with your jumps to 62W, when my AC is off CT is 0 (stable w/o jumps)

buennerbernd commented 1 year ago

In my installation I have 3 indoor units and one outdoor unit. All devices are powered by the outdoor unit. That are 4 devices in stand-by plus 3 esps. The CT is a value of the outdoor unit for the whole installation. All 3 ESPs are reporting consistent values. Perhaps 0,27A is the minimum step that can be reported. I will calculate the power consumption in stand-by for the coming hour…

absalom-muc commented 1 year ago

o.k. makes sense. The resolution of CT is 14/51A=0,2745A

buennerbernd commented 1 year ago

So, now I have checked after an hour. My calculated consumption is 0.0133kWh. The average power consumption of my whole installation in stand-by is 13.3 Watt.

@absalom-muc Could you please explain 14/51?

absalom-muc commented 1 year ago

@absalom-muc Could you please explain 14/51?

This is the factor to calculate the current from the data byte value, see here (just added)

HpNoTiQ56 commented 1 year ago

Thanks a lot for your help and clarification. I'm now ready to follow power consumption ! I didn't think that I would make such reactions! Keep up the good work ! I Close the issue !