• # Real power consumption of an ESP8266 on a net adapter

ESP8266-01 with 2 relais and a cheap chinese 500ma 5v Adapter:
Both relais off = 12mA = 2,76W
Both relais on = 22mA = 5,06W

Gruß M.
Edit:
I forgot to say that the measured mA are on the 230V side!

Strange though that your measurements are much higher than mine. Is it the cheap chinese adapter? the relays? the used “energy consumption monitor”?
However, even a continuos 5 W power consumption would lead to ≈ 9,5 Euros per year (Dutch rates).

Still curious what others will measure (if they do).

• However, even a continuos 5 W power consumption would lead to ≈ 9,5 Euros per year (Dutch rates).

At the rate 0.2 Eur/kWh - you pay about 8.76 Eur per year, if device run nonstop.

With Power supply efficiency of about 75%. The account will be one esp about 0.87 Euros per Year.

Pimatic = Smart Home

• Real measurements are mostly better than calculations. Problem in this case is that most power meters are very inaccurate at low power consumptions (say, 50% error or more around 0.5/1W).
There is a nice comparison between different power meters: https://nl.hardware.info/reviews/1460/6/vergelijkingstest-9-energiemeters-tabel-met-testresulaten
Here you can see that some even cannot measure below 5W, others are very inaccurate.
I have a Brennenstuhl PM231E, which is not very expensive though quite accurate at low power (if not dead on accurate it’s at least an indication). I bought it at Conrad.

About the 100-300mA: that is the maximum drawn current @100-230VAC. So an indication for the efficiency at full load would be:
Input: 230VAC * 0.1A = 23W or 100VAC * 0.3A = 30W (lower input voltage might give a lower conversion efficiency).
Output: 5VDC * 2.3A = 11.5W
11.5W/23W gives around 50% efficiency… Not very good, though not too bad on full load either.

I did some measurements with the HKLM 230VAC-5/3.3VDC supplies, they are quite ok (also see reviews on the internet). Most switching supplies use up to 100mA when not used and efficiency is reasonable. Nothing to really worry about as long as the devices are useful
Currently I’m only buying well built supplies as I am more concerned with safety (fire/shock) than price. Added benefit is that both power factor and efficiency are mostly better as well.

• There are many on the web.

At the rate 0.2 Eur/kWh - you pay about 8.76 Eur per year, if device run nonstop.

With Power supply efficiency of about 75%. The account will be one esp about 0.87 Euros per Year.

I do not exactly understand what you mean here. The efficiciency of the adapter or the power savings onthe esp?
If I measure 0,8 W continously over 7 hours I see no power efficiency on the esp.

• Real measurements are mostly better than calculations. Problem in this case is that most power meters are very inaccurate at low power consumptions (say, 50% error or more around 0.5/1W).
There is a nice comparison between different power meters: https://nl.hardware.info/reviews/1460/6/vergelijkingstest-9-energiemeters-tabel-met-testresulaten
Here you can see that some even cannot measure below 5W, others are very inaccurate.

I did read that same article before buying my meter

I don’t have one of them. I have a Koenig now.
The inaccuracy is also what bothers me. That is also why I’m questioning the differences in @Michael-Rudek measurements and mine.
And that’s also why I mention that in case his measurements are correct, a continuous 5W consumption leading to 9,5 Euro/year, is still acceptable.

• 5W would be quite something, but indeed, depending on the saving they realize it is quite acceptable. Don’t forget most relays have both a Normally Open and Normally Closed output: if the relay is used to only now and then switch something off then you should connect it through the NC output. Then you only need to actuate it while it needs to be opened.

• It indeed depends on what you use it for whether the costs are acceptible.
As mentioned: one of my nodemcus has 2 ds18b20s connected to measure my freezer and cooler. If my (vertical door) freezer is not correctly closed and everything melts I have a way more expensive bill than that 10 euros a year, apart from all the mess.
It already happened once and that is why I have installed that esp. (cooler is not so important)

• This cheap power meters are OK if you want to know what your Dishwasher, Washing machine etc. is consuming.
They are using hallsensors which are not very accurate.

If you want to measure small devices like this small 5v Plugs, it’s better to use a Multimeter “inline”.
The measurements i made in the second post are made with a calibrated Gossen-Metrawatt Multimeter.
By the way, I’m electrician
Or in German language : Energieanlagenelektronikerfachrichtungbetriebstechnik

• 5W would be quite something, but indeed, depending on the saving they realize it is quite acceptable.

You could use latching relais (aka bistable or impulse relais) (Stromstoßschalter). This way, you’ll get a more efficient design regardless of the switch state.

I think there are ready to use modules available http://wiki.seeed.cc/Grove-2-Coil_Latching_Relay/ or you can try to roll your own https://forum.arduino.cc/index.php?topic=362423.0

"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law

• The 5 Watt figure is purely hypothetical. Most relays wont consume anything close to this. I guess most need 10-100mA at 5V to stay actuated. Nothing to worry about.

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