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I'd like to measure some appliances in the house so I'm looking for something like this kill a watt meter that I can buy. Don't want to spend too much. Unfortunately that one is on back order of almost two months.

Any other suggestions?

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Commodore 64

Efergy makes a nice one that you can usually buy at the Massmart stores (Game, Makro, Builderswarehouse). But I cannot for the life of me find it online anymore.

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http://www.communica.co.za/catalog/Details/P1239073412

 

add a 15amp plug and a Janus connector to one of the above sonoff pows and you have a on/off switch with power metering, / logging,  provided the sonof pow can connect via WiFi to the internet.

They seems to be able to measure fairly low wattages and seem to be fairly accurate.

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Commodore 64

I wanted to also suggest looking at the DIN-mount power meters, but held off as they are usually quite expensive (eg the Carlo Gavazzi meters are about 1k), but I notice they come in around R350. Eg:

https://www.robotics.org.za/DDS238-2

These things are nice because with a bit of work, you can connect to it via RS485 and read the values using a software solution. Not right now maybe... but future potential is always nice.

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4 hours ago, plonkster said:

Efergy makes a nice one that you can usually buy at the Massmart stores (Game, Makro, Builderswarehouse). But I cannot for the life of me find it online anymore.

Had a look at the effergy they cost about R1300. 

 

1 hour ago, Arandoza said:

http://www.communica.co.za/catalog/Details/P1239073412

 

add a 15amp plug and a Janus connector to one of the above sonoff pows and you have a on/off switch with power metering, / logging,  provided the sonof pow can connect via WiFi to the internet.

They seems to be able to measure fairly low wattages and seem to be fairly accurate.

This looks like a very nice solution. 

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If you would like to measure the individual appliances I would lean more towards the SonOff as that is what they are build for. The Efergy is ok for getting a general idea of when you house is using a lot of power or not as it is measuring VA ( Determined by the V that you supply in the settings). The lekker thing abut the sonoff is you can re-purpose it of something else later , like a security light. Only down side is that you would not be able to check you geyser (Max 16a). 

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2 hours ago, PaulF007 said:

If you would like to measure the individual appliances I would lean more towards the SonOff as that is what they are build for. The Efergy is ok for getting a general idea of when you house is using a lot of power or not as it is measuring VA ( Determined by the V that you supply in the settings). The lekker thing abut the sonoff is you can re-purpose it of something else later , like a security light. Only down side is that you would not be able to check you geyser (Max 16a). 

Yea the inverter can already tell me what the total usage is etc. So gonna buy two of these SonOff devices and start measuring. Might re-purpose one to the pool pump.

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Commodore 64
14 hours ago, Tersius said:

Had a look at the effergy they cost about R1300. 

No, I'm not talking about the fancy one with the wireless LCD panel, they make a simple plug-in meter that looks like the Kill-a-watt that costs around R300. Even has a small NiMH battery inside so you don't lose your stats when you unplug it (except in mine it blew up, so I just removed it). I bought mine at Builders Warehouse. But I don't see them on the shelves anymore.

Looks a bit like this one. One of my favourite sellers too.

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Keep in mind most of these meters don't measure true RMS. i.e. it won't measure, or know about the Power Factor, and the VA values will be different from the Watt values. 

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Commodore 64
7 hours ago, SilverNodashi said:

most of these meters don't measure true RMS

I believe the Kill-a-watt and the Efergy I linked does take into account power factor. The Efergy I have even measures and displays the power factor. In my experience, the plug-in meters do take it into account while the CT-clamp type does not.

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6 hours ago, plonkster said:

I believe the Kill-a-watt and the Efergy I linked does take into account power factor. The Efergy I have even measures and displays the power factor. In my experience, the plug-in meters do take it into account while the CT-clamp type does not.

Which Efergy meter do you have?

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Commodore 64

This one. If you search ebay and even BoB you'll see it's essentially a generic china-model where the plug-bit at the bottom is an insert that can be swapped for different markets. On youtube there is a guy who disassembled this one, and if you keep looking you also find videos where someone did the same to a Kill-a-watt, if you watch both this meter seems to be a better option than the kill-a-watt, maybe even safer.. Someone even hacked into the protocol on the ribbon cable to get the data out out via USB.

I don't know how accurate it is, but it was definitely better than my OWL clamp meter (which I sold some months ago).

efergy.jpg

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On 2018/03/31 at 8:52 AM, plonkster said:

This one. If you search ebay and even BoB you'll see it's essentially a generic china-model where the plug-bit at the bottom is an insert that can be swapped for different markets. On youtube there is a guy who disassembled this one, and if you keep looking you also find videos where someone did the same to a Kill-a-watt, if you watch both this meter seems to be a better option than the kill-a-watt, maybe even safer.. Someone even hacked into the protocol on the ribbon cable to get the data out out via USB.

I don't know how accurate it is, but it was definitely better than my OWL clamp meter (which I sold some months ago).

efergy.jpg

Aha, ok. 

Do you know of any cost effective (aka not Fluke) clamp type meters, with logging? I don't want to leave Fluke meters with clients for a few weeks and this one will only measure the plugged in appliance's energy usage. 

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Commodore 64
11 minutes ago, SilverNodashi said:

clamp type meters

I'm not aware of any. I wanted to suggest looking at the Smappee, which is a whole house meter with more than one CT (up to 9 depending on model) and it does proper power factor as well... but unfortunately they are on the other side of 4k. Very very good though, they have disaggregation implemented, so they can distinguish appliances by looking at their "energy signature"... but not cheap.

I almost think the cheapest solution is a R500 modbus meter from aliexpress and a raspberry pi. For around 1k you can get the Carlo
Gavazzi ET112, plug it into a Raspberry Pi running Victron Venus and log the data to VRM. Total outlay around 2k. Of course I imagine the challenge is to get it down to below 1k.

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11 minutes ago, plonkster said:

I'm not aware of any. I wanted to suggest looking at the Smappee, which is a whole house meter with more than one CT (up to 9 depending on model) and it does proper power factor as well... but unfortunately they are on the other side of 4k. Very very good though, they have disaggregation implemented, so they can distinguish appliances by looking at their "energy signature"... but not cheap.

I almost think the cheapest solution is a R500 modbus meter from aliexpress and a raspberry pi. For around 1k you can get the Carlo
Gavazzi ET112, plug it into a Raspberry Pi running Victron Venus and log the data to VRM. Total outlay around 2k. Of course I imagine the challenge is to get it down to below 1k.

Thanx, I'll check it out. R2K isn't a lot, at least it's not R45k ;) 

The only difference is, those meters need to be installed in a DB, which isn't always possible without adding another DB. A clamp type would have been preferable but I have yet to find one. 

So, now to order one of these, and another Pi and see how it works

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Commodore 64
40 minutes ago, SilverNodashi said:

those meters need to be installed in a DB

Buy a small plastic distribution box with a DIN rail. Put the meter in it with the Rpi next to it, using one of these, some nice tension relieving grommets and a plug and socket on both ends. You also need an RS485 cable. You can get the Victron one, or you can get a similar one from another supplier but then you need to do some config changes to make sure it is correctly detected.

(The three little wires hanging out next to the usb plug on mine is wired to the serial headers, where Venus runs a debug console... easier than plugging in a monitor and keyboard and all that nonsense).

rpi_din.jpg

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