Wanted: Power Monitoring device

I have a couple plugs that monitor power consumption in watts. What I would like to have is a plug type of device that I plug my rack into to calculate a power consumption history. My Rack UPS shows instantaneous readout of watts and also KW.

My purpose is that my rack generates a lot of heat and I am wanting to size a minisplit AC unit appropriately. If the unit is too large, it will short cycle and there will be too much humidity in the room. If the unit is too small, it will possibly not cool the space.

The space is only 11x13. However, I have an 18U rack with two NAS units. One has eight drives and the other has six. The ambient temperature of the room runs 10-12 degrees over the house even with the door open.

So far, I am thinking that I consume around 2.6kw of power, which if true would generate about 9000btu of heat. My issue that number is a guess and I would like a device capable of graphing and tracking that energy consumption over time so that I can size a unit more effectively.

So far, I have come up with an Aeotec 6 plug, but I want to use something like Hubigraphs in HE to measure my power utilization. Any ideas?

Couple of questions:

It matters how you are currently powering your system. Is it one UPS being powered from a 120V outlet?

From a 120V circuit your rack would have to draw 21.6 amps to consume 2.6kW. That seems unusual.

The reason I ask if this is the case is, I have a Kill A watt P3 power meter. It cost me about $30. I always considered it a cheap inaccurate device until I had occasion to compare it to a calibrated laboratory grade wattmeter by Valhalla. The P3 was surprisingly close :slight_smile:

The thing is the P3 is limited to measuring <=1800 watts. And is only rated for 120V (i.e. no 240V) But if you are within these ranges, it accumulates actual kWh.

I realize you are looking to plot your energy usage. I also know that many "hobby" Z-Wave power devices are less that laboratory accurate.

Any power monitoring switch should work. I have some iris ones, zooz zen15, monoprice I have mine going to prometheus and grafana (you have a server rack so Im assuming docker should be in your wheelhouse).

Mini splits run at a variable speed, so oversizing isn't as much of an issue. I will say they do have trouble dehumidifying since they have smaller coils than a central ac. Also less air moves past the coils. Oversizing helps if you get a bigger indoor unit since there is more coil space.

Also, if your ups has a usb output, there are plenty of programs that use a raspberry pi or docker that can take that usb and turn it into much better capability than powerchute or whatever software came with the ups. That can then be output to influxdb or prometheus.

I mean if your sizing a mini split, water usage shouldn't matter as much as desired temperature/humidity results. If your doing a dedicated solution for one small room, 9k btu mini split and a dehumidifier should be able to work, but I dunno the rest of the variables for the home.

I am quite certain that I am not drawing anywhere near the 2.6Kw. That's actually the amount of power by my calculation that a 9000btu minisplit could displace in terms of heat. The rack runs a Unifi Dream Machine Pro, a Unifi Switch 24-250W, a Unifi Switch 16-150W, and a QNAP TS-1277 with eight 10TB WD NAS drives. On the other side of the room, I have a QNAP TS-877 with six 8TB WD NAS drives. My Cyberpower rack mount UPS shows a power draw of 0.234kw which just flat out sounds wrong. I have heard the Kill A Watt meters are good, but in my understanding they are not in any way network connected.

That is correct. However the cumulative function will provide you with total kWhours used over the time the device is connected. So if you plug it in and allow it to run for a few days (or more) a press of the righthand red button and the device will read out the kWh used since connected. Another push of the red button will tell you the hours over which those kWh were collected.

Would seem to be exactly what is needed to size and A/C unit.

If you really need something connected to Hubitat, the Zooz Zen15 should work. It does pretty well with inductive loads (hard drives/delta fans) and can actually handle high wattage. I've been using one with a 15,000 BTU window unit for a while with no issue. Just make sure you have a good Z-Wave signal to it.

Those Kill A Watts are pretty awesome though. I've seen someone run a shop vac, heat gun, and angle grinder through it all at once. I wouldn't recommend doing that but I know it can handle a load.

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