Plug-in power meter

How do you know? Does it measure Power or VA? Can it show the power factor. Pretty essential on modern equipment with SMPS.

If it doesn't measure power factor then it may well overstate standby power resulting in un-needed un-plugging in the quest of imaginary power savings....

Dave G4UGM

Which is why I included the word "seems". According to the dehumidifier manual, the rated Input Power/Current is 188W/1.0A (27°C, RH60%). When I first turned on the dehumidifier it showed the humidity was 70% and the room temp was about 18°C. The power meter showed 170W. That didn't seem unreasonable to me. Over 6 hours, with automatic control of humidity set to 60%RH, consumption was shown as 0.5kW (it shows to only one decimal point). When I have an opportunity to turn it on, I'll try it with my shredder (motor rated at 2.5kW IIRC). It'll be interesting to see how it deals with a high-power inductive device.

It doesn't have an ability to show power factor, but I use my other power meter almost entirely for resistive heating (fan heater), and the new one will be used for the same. Not sure what you expect for a device costing £5.99 anyway!

its low power capacitive devices that seem most problematic. You are not going to use the shredder for many minutes...

Not a lot, but if I am really trying to save money it would help to know if its real power or not.,..

Dave

Thanks for the headsup: following your tip I bought one yesterday.

Funnily enough, one of the first things I tried it on was a mini-dehumidifier which runs off a 9v wall-wart. The next thing I tried was a mains powered table fan.

Why should this be interesting? Because they were plugged into adjacent sockets on a twin-gang outlet and after I unplugged the wall wart from the Silvercrest Plug-in power meter I plugged it into the empty socket and then plugged the table fan into the power meter which was still in the other socket..

...at which point the wall wart blew up.

Literally.

With a Bnag! and the letting out of all the Magic Smoke.

And the top blew off and flew across the room. (It was a small room, mind.)

I presume the wall wart's time had just come and I hope the presence of the power meter was coincidental - I can't see how it could have influenced anything like that - but I thought I'd just mention what happened anyway.

Nick

Wow! Looks like a capacitor in the SMPS wallwart blew. Must have been pure coincidence, but more than a little unnerving. Out of interest, did the power meter show anything vaguely accurate with the wallwart power supply? Unless designed for them, they don't tend to be accurate with an SMPS. I'll have to try one with a 60W SMPS for another dehumidifier I have to see what it shows.

My digital multimeter and this powermeter each show my mains voltage to be the somewhat unlikely 243v while my analogue multimeter shows the more expected 230v. So given that possible variation, yes, the results with devices with known outputs were pretty close to expectation. Close enough that I'd believe that the one or two items which read differently are probably running out of spec. As for the wall wart: the mini-dehumidifier claims to consume 24w and the powermeter was telling me that its wall wart was consuming 25w under load.

Nick

At a time of minimum use , ie only have on standby units that you have you keep on , unplug the fridge/freezer and anything else intermittant like laptop chearger etc, for an hour if possible and note the teadingson the utility meter. And then an hour of something of constant highish consumption , noting readings on utility meter and plug-in-line meter , and compare compensated readings

If it's an Inkbird it would be because it tries to take 40W from a 27W PSU. They are always overheating and blowing up.

I'd say 243V isn't unlikely, voltages up to 253 are within spec, mine tends to be at the upper range, though I don't think I've measured it since they local substation was on-generator for a week while they "did something" to it ...