Help figure out what this device is - driving me crazy

I’ve got a device that has been driving me crazy for quite a while, cannot figure out what it might be. It runs at all crazy times day or night, often when it seems nothing other than always on stuff is running. It is not something that a human is turning on or off. It goes when all HVAC is off. Sense suggested it might be a light, computer, TV, Heat Pump, HVAC or Humidifier. I know it is not a light, computer, TV, heatpump, HVAC and don’t have a humidifier. ARG !!!

Hi @32259fl. No immediate guesses here, but I can see why Sense thinks it could be a computer.
Example of what a Macbook looks like while it’s charging below - similar frequent “choppy” waveform operating between ~40W - 80W.

It also looks like the waveform changes towards the left of the meter if you go further back - can you post a screenshot of what that section of the waveform looks like as well?

I have a desktop computer, and it, monitors and external drives are all plugged into a TP-Link energy plug so are recognized as one item. My wife does have a very small notebook, but it would not be doing anything at night. Here is some earlier part of the graph that you asked about:

I think it looks like some type of battery charger. Do you have any UPS on your computers? Do you have any battery operated tools with the battery in a charger? How about your home alarm system? A battery backed up garage door opener?

The power signal starts high and drops off, but way too slow to be a thermal effect (i.e., not any type of heating element). Battery chargers slow down as the battery gets full, so that’s why I’m focused on them. The overall power is fairly large, so I would look for automotive size batteries. (We’re not talking rechargeable flashlight or MP3 player).

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FYI, you can’t use this waveform as a 100% signature; this view is what sense thinks is the waveform. To see the true wave form, you need to look at the whole house meter view for these times that you know the device is on (even though you’ll be seeing other devices in the whole house view of course).

Having said that, it does look like a battery charging circuit of some type, doing a top-off, so I think @demiller9 is probably correct. Please let us know what you find out, when you find out.


Yes, I have quite a few UPS units on almost all my sensitive electronics. However this was only recognized perhaps the first week in November. All the UPS units have been installed from when I first moved into the house two years ago as has Sense. Since the computer systems are off at night I would not expect to see that many charging cycles, and at times during the day when they are on I often see none of this.

The only other thing that has changed in the house is that we replaced our electric hot water heater with a hybrid heatpump unit, but that was the last week in November. This device 3 is often on when the heatpump is off and off when the heat pump is on, plus this started about three weeks before the heatpump went in. Also I would thing the heat pump would draw more than this and not have this strange a pattern.

See my reply to the post above as well. Not sure why I would need to look at the house pattern, as I have seen this late at night when the only stuff on were two outside lights and the always on items.

The reason to look at the main Power Meter vs. the device-specific Power Meter waveform, is that the Sense device waveform is NOT a measured waveform, while the one reflected in the main Power Meter is. Sense generally does a good job of capturing / predicting the detected device waveform, but it is not guaranteed to be the same as what the actual device is using - the device waveform is what machine learning predicts the waveform to look like. The main Power Meter offers you a higher fidelity view of what is really happening, especially in the early hours when you don’t have lots of other devices waveforms buried in the whole house measurement.