# Energy Monitoring Plug

Hey guys,

Voltage I get, but what are the other values?

Current 550

Current consumption 10.1

Voltage 247.8

I assume current is being measured in mA since 550A is a ridiculous number. Current consumption is usually the power draw in watts. Iām not sure if your current number is correct though. Can you send a screenshot of what you see in home assistant. Also what plug/hardware are you using for energy monitoring?

1 Like

Thanks mate,

Sorry, I should have added that info in the first place LOL. This is a plug iāve added though local Tuya. Its a Brilliant Plug (not sure of the model)

Ok that makes more sense now. I believe your current in the photo is 52mA. The current consumption is your power draw as 10.1W and your voltage is 249.7V. Assuming your countryās nominal voltage is 240V, the actual voltage at the time was slightly higher. Donāt worry, the voltage in your socket does fluctuate and this is normal. Appliances are designed to operate within a margin of error (e.g. 230-250V) but this depends on your country. Whilst itās nice to know the voltage, it isnāt that useful by itself. Current is measured by your device in mA and here in the UK at least, standard wall sockets can supply 13A. Again this will vary between countries.

Where things get a bit confusing is power. In high school physics you are taught P=IV or power = current x voltage. Whilst this is true for DC, this doesnāt really work the same way for AC.

There are actually 3 types of AC electrical power: Real Power, Reactive Power and Apparent Power. Real power is measured in Watts (W) and this is the most important number. I donāt know if itās the same for every country but here in the UK you are charged in pence per kWh (p/kWh). A kWh is the amount of energy that a device would use if it consumed 1000 Watts for 1 hour. I know tuya plugs donāt give this number in Home Assistant even though it is available on the app. There are ways of getting around this in Home Assistant by calculating the kWh if you know the Watts a device has consumed over a period of time.

Reactive Power is power a device consumes if the load has something known as reactance. This is either inductive or capacitive. If youāve studied physics you might have come across inductors and capacitors. Reactive power isnāt a concern in households since you arenāt being charged for it. However, industrial consumers who might have really powerful motors which act as big inductors will generate a big reactive power demand. Reactive power is difficult to generate so is much more expensive than real power. But all you need to worry about at home is real power where your devices and appliances are measured in watts. The lower the number, the less it costs to run.

Apparent power is just the combination of the real and reactive power using trigonometry. This triangle might explain things in more detail. Your tuya plug measures real power in watts which is what you are being billed for at home. You might notice your numbers 249.7V x 0.052A ā  10.1W. Actually 249.7V x 0.052A = 12.98VA. VA is just the unit for apparent power. 10.1W is your real power so you have some mysterious reactive power which you get from your energy supplier for āfreeā. If you want to go in depth, there are plugs available ATHOM which are pre-flashed with a FOSS firmware called Tasmota. They actually give you a LOT of information about your electricity consumption.

This is what it looks like in my Home assistant dashboard. I hope this long winded explanation hasnāt made things too confusing. Feel free to ask if none of it makes sense.

TL;DR Current = 0.052mA, Power = 10.1W. Lower power number is cheaper. High power number is more expensive.

2 Likes

Wow, thanks mate!

Appreciate you taking the time to explain all that, very informative

Iām in AU so same power (240v 10amp?) but we have the type I plug. Which IMO is better (smaller footprint). After flashing tasmoto and then ESP home on to a few plugs round the house, iām hooked. Interesting you mention Athom. Ive been looking everywhere for them. But so hard to find with the type I plug.

The only one Ive found is this.

Where are you getting yours from?

No problem. I know AC was very confusing to me when I first learnt about it. Thatās definitely funky looking plug but yes far less bulky than what we have. Funnily enough, I found this wiki page about your electricity standard. You might know more than me about it but looks like you guys have a socket variant that goes up to 32A which is crazy! But as you said normal sockets only go up to 10A.

With regards to the smart plugs, I purchased the ATHOM Tasmota plug from their AliExpress store. I can see you have found the Aussie plug but they only have the Homekit flashed model there. You said you canāt find the type I plug but is the link you found not a type I plug? Iād choose Tasmota personally but there might be a way to integrate Homekit devices in HA. Tasmota easily integrates with MQTT so the setup is really straightforward. The ATHOM official website looks like it has the Tasmota model available. I havenāt made a purchase from their site though.

I know the pain of trying to find a plug that does energy monitoring, is available for your plug and also doesnāt rely on Tuya. The Tasmota website says Tuya has updated its firmware and is currently unable to use tuya-convert to flash it with Tasmota or ESPHome. Itās a shame though because there are so many plugs listed on the Tasmota site which are no longer compatible. Here in the UK Iāve only found TP-link plugs which use their own firmware and they sort of work with HA or the ATHOM plugs. The rest arenāt worth it IMO.

Yes! I havenāt seen one of those for a while though. When I first started in IT, I worked in a small company that used them in the coms room for the racks.

This was the only one I could find, I think from reading though it, that it means home kit though home assistant. Thatās what I looks like to me (its what Im hoping)

Ill have to check out the Athom site, maybe I can buy directly from there.

It just really gets to me that we are forced to use cloud connections for our plugs. Tuya Local is fine for now, but how long till they change the API and it all breaks.

Iām only going to buy things I can use locally, I get that its a small segment of the market (most people have no idea sadly) but its still one you would think would be better catered for

From what I understand, Athom provides 2 models for each smart appliance. They are physically identical but one is flashed with firmware to make the device compatible with Homekit if you are already invested in Appleās ecosystem.

The second is the better option in my opinion which is tasmota since it is open source, easily integrates in HA etc. Athom are the only company that sell products preflashed with an tasmota from what Iāve found. It might just be a case that the tasmota variant is out of stock on AliExpress? But I can see their official site stocks both variants for the AU plug.

If youāre not too fussed about the energy monitoring, sonoff also make a few products that are easily programmable with tasmota. Who knows, they might come out with energy monitoring plugs soon enough.

I 100% agree with you that cloud based products are definitely frustrating and I can imagine it being an even worse problem in the future. Iāve even started seeing products charging a monthly subscription fee for integrations with services like IFTTT! Tasmotaās site says even old Tuya hardware automatically upgrades the firmware if it connects to the Tuya app and canāt be reflashed. Others are finding newer tuya plugs which use different microcontrollers to the standard Espressif platforms and open-source firmware isnāt available (yet?).

Companies need to make money somehow and the more āsmartā features they add means an added cost to the customer. And at the end of the day I think most people just want a product āthat just worksā. Companies might also make an argument that custom software might be potentially harmful to the product, or even the user. I donāt know all the legal rules about open source but Iām sure there the day will come someone is fatally injured from a smart device and the manufacturer will point the blame to the user who installed their own software claiming that was the reason for failure.