Comments on: HOPI Meter power consumption analyzer https://www.epanorama.net/blog/2023/06/07/hopi-meter-power-consumption-analyzer/ All about electronics and circuit design Sun, 19 Apr 2026 21:53:56 +0000 hourly 1 http://wordpress.org/?v=3.9.14 By: Tomi Engdahl https://www.epanorama.net/blog/2023/06/07/hopi-meter-power-consumption-analyzer/comment-page-1/#comment-1820509 Sat, 06 Jan 2024 20:09:22 +0000 http://www.epanorama.net/newepa/?p=193282#comment-1820509 For those who haven’t seen the “bigclive” yt channel I present the marvel of shady and dangerous chinese electronics from AliExpress – the HOPI with its lovely live 240VAC speaker terminals. (Sorry for photo on the shiny stove, i.m using it as workbench, and the exposure time must be long due to slow multiplexing of the display). This device is unique in many ways – it contais a really advanced Cirrus Logic CS5463 smart meter chip, and inside it’s quite well made, yet it features a battery compartment lid (probably case from another meter) revealing bare contacts (you can also see the current shunt), and the lovely live speaker connectors. Also note that when using an european plug there is no earth continuity due to construction of the HOPI’s universal socket.

It shows current, RMS voltage, frequency (misspelled as frequence), active power, and power factor. Seems to measure quite well. This version is rated 20A, however when drawing more than 10A (water kettles, and so on) the shunt begins to heat noticeably, also the socket is rated 13A. It can also go crazy when dealing with bizarre power factors of 0,05 and less, like with capacitor droppers.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2023/06/07/hopi-meter-power-consumption-analyzer/comment-page-1/#comment-1806830 Tue, 27 Jun 2023 10:07:25 +0000 http://www.epanorama.net/newepa/?p=193282#comment-1806830 What the heck! Series capacitor makes fan go TURBO!
https://www.youtube.com/watch?v=LZkJJAissM4

I was disassembling a fan to reverse engineer its electronic humidity control and experimentally put some capacitors in series with the fan to slow it down.

No series cap 242V 14.5W 90mA (0.66PF)
220nF the fan struggled to turn – 95V 1.5W 22mA (0.27PF)
470nF the fan ran at about 1/3rd the power – 157V 5.5W 51mA (0.43PF)
1uF the fan ran at SUPER TURBO POWER! – 300V! 24W 120mA (0.8PF)

I’m guessing I may have hit a perfect inductor/capacitor combo to result in such a dramatic result by somehow creating a phase shift that added to the supply voltage.

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