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    • CommentAuthorvord
    • CommentTimeMar 1st 2016
     
    Any recommendations for a fairly low cost electricity monitor which can display real time data and record data over time? Ideally I would have one for each of 2 consumer units which are inaccessible so wireless display would be necessary.

    I'm trying to work out why my electricity usage keeps on going up. It seems to have risen from £1.50/day to £2.50/day over a couple of years (calc assuming 11p/kWh). I've a fair idea it might be something to do with the huge fridge and oven the other half wanted, but would like to see where economies might be made.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 1st 2016 edited
     
    This is what I use for the monitoring. You can buy extra clamps and an optical sensor.
    http://www.ebay.co.uk/bhp/current-cost-envir
    Then I connect it to a Raspberry Pi for the logging.
    Going to cost you about £100 to get it all sorted.

    And CurrentCost went bankrupt recently and not sure if they have phoenixed or not.
    • CommentAuthortorrent99
    • CommentTimeMar 1st 2016
     
    Posted By: SteamyTeaThis is what I use for the monitoring. You can buy extra clamps and an optical sensor.
    http://www.ebay.co.uk/bhp/current-cost-envir" rel="nofollow" >http://www.ebay.co.uk/bhp/current-cost-envir
    Then I connect it to a Raspberry Pi for the logging.
    Going to cost you about £100 to get it all sorted.

    And CurrentCost went bankrupt recently and not sure if they have phoenixed or not.


    Hmm that's interesting that CurrentCost device looks identical to the EON branded device my dad gave me (including the USB data cable).

    Do you link the RPi using the USB cable or the Network bridge device? What software do you use to suck the data out of it?
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 1st 2016 edited
     
    It is the same as the EON one.
    I use the USB cable as I can then use the default sample time of 6 seconds (ish).

    I wrote my own script (actually modified others). Then installed Upstart so that it was live as soon as the RPi boots up.

    #!/usr/bin/python

    import serial, time, datetime

    while True:

    #Open the USB Serila port
    cc128 = serial.Serial("/dev/ttyUSB0", 57600, timeout=6)

    #Read the USB Serial port
    text = cc128.readline()[:]

    #Splits up the data
    length = len(text)
    dsb = text[32:37]
    time = text[49:57]
    temperature = text[70:74]
    sensor = text[89:90]
    sensorID = text[103:108]
    ch1 = text[139:144]
    ch2 = text[170:175]
    ch3 = text[201:206]


    #Sort out the time format
    timestamp = datetime.datetime.now().strftime ('%d/%m/%Y %H:%M:%S')

    #Opens and writes to the text file where the data is stored
    tfile = open("/home/pi/homemonitoring/ccdata.csv", "a")
    tfile.write("%s"%timestamp + ",%s"%length + ",%s"%dsb + ",%s"%time + ",%s"%temperature + ",%s"%sensor + ",%s"%sensorID + ",%s"%ch1 + ",%s"%ch2 + ",%s"%ch3 + "\n")
    tfile.close()

    time.sleep(6)
    • CommentAuthortorrent99
    • CommentTimeMar 1st 2016
     
    Excellent that's perfect thank you! Another job for the Pi 2 or the Pi Zero or should I upgrade to a Pi 3? decisions decisions...... :wink:
    • CommentAuthorEd Davies
    • CommentTimeMar 1st 2016
     
    Shame how the forum chops whitespace off the start of lines when it's significant in Python. Perhaps you could put that on pastebin or as a github gist or something, Steamy.

    A word of warning though: those CurrentCost devices vary a lot from version to version in what they output so Steamy's code might not work exactly as is for newer ones. Should be easily modifiable, though. Mine puts out XML and I did some quick and dirty code to parse that (also in Python) using the default Python DOM implementation. It relied on a one second timeout to determine when a burst of lines (which come, as Steamy says, every 6 seconds) was complete.
    • CommentAuthorEd Davies
    • CommentTimeMar 1st 2016
     
    Here, by the way, is the code I did to read from the CurrentCost. It has multiple threads: one to read blobs of characters from the serial port delimited by the gap in time between samples and one to process those blobs into XML and log them.

    https://gist.github.com/ed-davies/4e2e4045c103e2946135#file-current_cost-py

    The original idea was to be able to have other similar logging activity running in the same process. However, when I came to do code to talk modbus over the LAN to my Morningstar PV charge controller I decided to do it in JavaScript in Node.js as it deals with this multithreading more natively. Consequently, this code didn't progress beyond the prototype test code at the end. Might be of interest, though, as it tells you a bit more about your particular device is outputting.

    Something to note is that not all the messages from the CurrentCost are the same. At some interval (one an hour?) it also outputs a summary of readings over a longer period. IIRC there's some way to force it to do that on request, like reset it, but I can't remember the details.
    • CommentAuthorvord
    • CommentTimeMar 1st 2016
     
    Thanks, the multiple channels will be very handy for what I want to do. Looks like the CurrentCost EnviR is supplied free by some electricity suppliers and new ones are finding their way directly to eBay quite cheaply. I shall try to bag one of those.
    • CommentAuthortorrent99
    • CommentTimeMar 1st 2016
     
    Having trouble locating the power supply for my EnviR, anyone know what voltage warthog I'm looking for please (before I plug something in that fries it)?
    • CommentAuthorEd Davies
    • CommentTimeMar 1st 2016
     
    Sorry, mine's in storage about 30 km away so a bit awkward to check Hope somebody else can help.
    • CommentAuthortorrent99
    • CommentTimeMar 1st 2016 edited
     
    Found it! For future reference it's a small warthog with a slightly smaller jack than most of the 12V/9V items around. Output according to the label is 3V at 80ma, I measured 4.5V (no load).

    Also in case anyone wants to wire their own "data cable" I found this pinout info:


    http://currentcostgadgeteer.codeplex.com/

    1 Vcc supply
    4 Gnd
    7 EnviR Unit Rx Data
    8 EnviR Unit Tx Data
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 1st 2016
     
    I power the CurrentCost from the 3.3 or the 5V pin on the RPi no problem.

    Ed
    My initial codes was written by someone else and that hourly, morning noon and night, daily, weekly and monthly output used to cause all sorts of problems.
    Why, with my very limited understanding of coding, I simply split the line up.
    I have a later version that does a conditional check on the line length and only saves when the length is correct. Bu tit is messy and probably not reliable (I have one at a bakers at the moment and must go and check it.

    Also worth knowing that the RPi does not have a clock, and can be flaky on its timekeeping even when connected to the internet.
    •  
      CommentAuthordjh
    • CommentTimeMar 1st 2016 edited
     
    Posted By: SteamyTeacan be flaky on its timekeeping even when connected to the internet.

    If you have a connection to the Internet your timing should be perfect. You need to set up an ntp daemon (Network Time Protocol). googling 'pi ntp' throws up lots of likely how-to hits.

    Edit: PS the sheepwalk RPI3 one-wire plug-in also contains a clock.
    •  
      CommentAuthordjh
    • CommentTimeMar 1st 2016
     
    BTW, has anybody found or used any one-wire current sensors?
    Ive seen this:

    http://www.hw-group.com/products/sensors/30A-Current-probe-1W-UNI_en.html

    but haven't looked closely or investigated yet.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 1st 2016 edited
     
    • CommentAuthortorrent99
    • CommentTimeMar 2nd 2016
     
    Posted By: djh
    Posted By: SteamyTeacan be flaky on its timekeeping even when connected to the internet.

    If you have a connection to the Internet your timing should be perfect. You need to set up an ntp daemon (Network Time Protocol). googling 'pi ntp' throws up lots of likely how-to hits.

    Edit: PS the sheepwalk RPI3 one-wire plug-in also contains a clock.


    You can also add a real time clock module for a couple of pounds from the bay. Probably easier to use NTP though.
    (Mind you my OSMC seems to have REAL difficulty keeping time despite supposedly using NTP, my latest thing has been to set up a cron job to manually update the clock from NTP every 15 mins. It's a mystery!)

    Is there such an animal as a multiplexor for the 1 wire sensors around for the Pi (so you can have LOADS of sensors)?
    •  
      CommentAuthordjh
    • CommentTimeMar 2nd 2016 edited
     
    Posted By: torrent99Is there such an animal as a multiplexor for the 1 wire sensors around for the Pi (so you can have LOADS of sensors)?

    the sheepwalk RPI3 one-wire plug-in

    Edit: PS: ntp is pretty reliable. If you dig hard enough I'm fairly sure you'll find a misconfiguration somewhere.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 2nd 2016
     
    I use RTCs and ntp, it still gives me grief. Could well be something I a doing.
    •  
      CommentAuthordjh
    • CommentTimeMar 2nd 2016
     
    • CommentAuthorrhamdu
    • CommentTimeMar 3rd 2016
     
    One point that nobody has mentioned, I think: if you have solar or other microgeneration, you really want a monitor which can sense which way the energy is flowing (into or out of the grid). This is not the case for our monitor, an oldish Current Cost, bought before we installed PV. It is now basically an expensive room thermometer.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 3rd 2016
     
    You can get two opti-sense Envi monitors, that should so it.
    But it is probably easier to just get a smart meter fitted (roll out year this year, just like last year and 2014 was).
    • CommentAuthorvord
    • CommentTimeMar 5th 2016
     
    Thanks for the recommendation. I bought an Envi R from eBay heavily subsidised by e-on. :bigsmile:

    It is a surprise to find I am consuming 500W without anything really being switched on. Half turned out to be the fridge and freezer, but of the other half there isn't much that really needs to be on. It will be a useful tool.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 5th 2016
     
    Your fridge and freezer should not be using 250W. How old are they and are they switching off?
    I found out my fridge was faulty when I noticed that my usage had gone up by 3 kWh/day.
    • CommentAuthorvord
    • CommentTimeMar 5th 2016
     
    I think the fridge is working properly. It's one of those silly Samsung american style things which despite being A++ rated uses about 600-700kW/h per year which averages out at about 70W continuous. I measured 171W when it was running and it does switch off. The freezer is an old second hand thing running about 85W continuously. I might see if the other half really needs it now she has the silly fridge freezer.

    There is still a fair drain with everything switched off. The building was commercial and I've still not removed the emergency exit lighting which must be worth 100W on it's own.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 5th 2016 edited
     
    It is good fun hunting down vampire/phantom loads.
    Now you got a Envi, you going to connect it to a Raspberry Pi?

    It is also worth getting a plug in energy meter to test individual items.
    • CommentAuthorvord
    • CommentTimeMar 5th 2016 edited
     
    I'm not planning to log just yet - I have a monthly log of electricity and gas consumption and gas is coming down nicely. It's the steady rise in electricity consumption I want to turn the other way around and the EnviR should be helpful. I might well buy a plug in.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 5th 2016
     
    Logging is useful for looking at night time usage though.
    If you were local I would lend you one of mine, but I don't think you are nearby.
    • CommentAuthorvord
    • CommentTimeMar 5th 2016 edited
     
    The electricity meter has daytime and night readings. I hadn't previously normalised the night reading with the day reading (day = night * 2.42 for a 17 hour day and 7 hour night to get them on the same scale). Looks like just about all of the electricity is used by stuff that is on all the time. That is really wasteful.
    • CommentAuthorvord
    • CommentTimeMar 15th 2016 edited
     
    Would you believe it - the cheap plug in energy monitor from eBay (the one with 4 blue buttons bought before the Envi R) uses 17 watts of electricity! Imagine plugging a few of those in to try to figure out what is using all of your electricity. :shocked:

    I'm down from 500W to 230W continuous so far, with another 40W phantom current on a lighting circuit and upstairs sockets that can probably go once I figure out what is using it. The biggest reductions were switching the fridge to eco mode and the other half turning things off when she saw the monitor.
    • CommentAuthorskyewright
    • CommentTimeMar 15th 2016
     
    Posted By: vordI'm down from 500W to 230W continuous so far, with another 40W phantom current on a lighting circuit and upstairs sockets that can probably go once I figure out what is using it. The biggest reductions were switching the fridge to eco mode and the other half turning things off when she saw the monitor.

    When you get to those sort of levels, power factor errors can loom large. The currentCost makes fixed assumptions about power factor and voltage. If all that's left running is a few switch mode PSUs the figure shown on the CC may be significantly more than reality. I spent ages trying to find out why I was seeing around 150W when I was only expecting around 80W (both figures v. approx from a dim dark corner of my memory). I only found the solution (which was that there was no extra load, just a false reading) by waiting till a quiet day with no one else around, powering the CC itself from an unplugged UPS, and turning off each of the known (& individually checked using a plug-in monitor) 24/7 loads one by one. As each device was taken out the CC reading dropped by more than each device accounted for. With all known loads off the CC reading was zero...

    YMMV.
   
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