Solved Interesting 20w Spikes every 5 seconds!

I was noticing a strange 17-20w spike every 5 seconds on my Sense energy monitor. I had not been paying attention to it so do 't know how long it was going on. Recently did a hard reset and trying to clean up my devices. I looked and looked and could not find it. I finally unplugged my iMac (Retina 4K, 21.5-inch, Late 2015) and restarted it and bang, disappeared. I have no idea what was happening on my iMac but that momentary spike every 5 seconds went away. Here is a photo of the spike noise I was seeing for reference.

Good catch, however, hz is per second, not per minute.

I totally knew that. I have no idea why I wrote that! Will edit it out!

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Hey @noel.hastings. I have my MacBook Pro (16-inch, 2019) charger on a smart plug and see some similar behavior for it when it’s actively charging.

Zoomed out view:

Zoomed in:

I have a similar behavior when my PC desktop computer and associated devices are on. I get few Watts spikes each 2-3 seconds.

I never investigated it, but am now tempting to do so shortly. All my devices are plugged into the same UPS battery pack. I’m not sure which component will require a hard reboot!

Following screen capture shows before and after I put my desktop to sleep and turn off all monitors. Mini spikes are present only when desktop/monitors are on.