Home  5  Books  5  Magazines  5  News  5  GreenPro  5  HelpDesk  5  Your Cart  5  Register  5  Green Living Forum
Not signed in (Sign In to the Green Building Forum)

Categories

This month's favourite choices


Vanilla 1.1.4 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
 Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications:: Apply now.




General: PV compatible domestic energy monitor...

Bottom of Page

1 to 30 of 43

  1. <
  2. 1
  3. 2
  4. >
    • CommentAuthorjms452
    • CommentTimeJun 7th 2012
     
    I’ve been trawling forums products for a while now trying to find a PV compatible energy monitor – One that shows how much energy we are importing - rather than one which shows us using power during the day when we’re actually selling it (like our OWL).

    I thought that I had it with the optismart but for some reason it can’t cope with having no pulses during the day.

    And I know I could stand there toggling lights on/off to work out if I’m importing/exporting but this isn’t what I’m after.

    At present we have: 3600TL-20 + sunny beam and an owl(oldish-non-usb)
    • CommentAuthorSeret
    • CommentTimeJun 7th 2012 edited
     
    AFAIK without changing your wiring your choices are pretty limited. Either splash out on a Wattson, or DIY it with an Open Energy Monitor.
    • CommentAuthorjms452
    • CommentTimeJun 7th 2012
     
    Ah ha - Thanks Seret
    Do you mean the Wattson Solar Plus? Anyone tried it?

    Is this similar accuracy at low use to the OWL (i.e. I notice its current clamp based)
    • CommentAuthorskyewright
    • CommentTimeJun 7th 2012 edited
     
    Posted By: SeretAFAIK without changing your wiring your choices are pretty limited. Either splash out on a Wattson, or DIY it with an Open Energy Monitor.

    Or consider a Brultech? That still uses a clamp but also uses a special PSU so it can take into account both voltage power factor. I don't have one myself, but I seen the Brultech units highly praised by people over on the Navitron forum who have them.
    N.B. As the Brultech is non-UK I'm told you have to be careful when placing an order to make it clear that you will be using it with UK mains, so that you end up with the appropriate PSU.
    • CommentAuthorSeret
    • CommentTimeJun 7th 2012
     
    The Emon can also do voltage measurement but not through its power supply, so it takes up two plugs:

    http://openenergymonitor.org/emon/applications/solarpv

    Hopefully they're going to start selling them pre-assembled, if so they could be a really good option for a lot of people.
    • CommentAuthorSprocket
    • CommentTimeJun 8th 2012 edited
     
    Similar situation to jms here but something a bit more industrial needed.

    I'm looking for a simple wired ethernet (or modbus) solution for three phase. I don't need (can't use) local display or lights or USB or wireless.
    It'll be installed at the meter - which is well away from any inhabited buildings but the room is networked.
    And it must be able to cope with solar so I can properly see import/export at different times of day.

    I don't mind spendinga bit forthe right part but given the cost I am wary of ending up with something that can't do what I want.

    I don't have m-bus or a smart meter. Just a old-style spinning-disc 3-phase (1x100A) meter. So I assume I am looking for something using 3x CT-clamps on the wires plus 4 wired connections for voltage. If there is a better way any ideas are welcome (should i ask elec board for a meter upgrade maybe?). A small amount of homebrew is acceptable but I don't really have time to build the whole thing myself right now.

    Any suggestions?
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 8th 2012 edited
     
    • CommentAuthorjms452
    • CommentTimeJun 8th 2012
     
    Looking at the wattson this looks like it will do the job but being current clamp based isn't going to give a great reading at low power levels.

    On my quest for perfection I see the TXact accessory for the wattson which plugs into your generation meter and gives you pluse based (i.e. fully accurate) generation - any one tried it or have any thoughts?

    http://www.amazon.co.uk/Wattson-Solar-TXact/dp/B007ZLQD6W/ref=sr_1_1?s=electronics&ie=UTF8&qid=1339143586&sr=1-1
    • CommentAuthorborpin
    • CommentTimeJun 8th 2012
     
    Posted By: SprocketAny suggestions?
    The OpenEnergyMonitor has all the connections for 3 CT clamps. Not quite 'out of the box' solution though.
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 8th 2012
     
    I haven't seen ANY clamp solution accurately measuring generation by my PV system, and I've tried several, I suspect because the current waveform is a poor match to the voltage of the mains that energy is injected into, ie the signature of microgeneration looks nothing like the mainly-resistive consumption that most of these devices are presumably tweaked for.

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 8th 2012
     
    There are some generation meters that have a light permanently on when exporting. The circuitry for that cannot be too complicated. A rectifier is basically a two input, one way device, is that an OR in Boolean. One on the import side, one on the export side, then some way to sense the difference, or an I talking complete testicles (I think they are something electricians use for testing circuits).
    • CommentAuthorSeret
    • CommentTimeJun 8th 2012
     
    Posted By: SteamyTeaThere are some generation meters that have a light permanently on when exporting.


    Mine does that. Blinky red when importing, steady green when exporting.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 8th 2012
     
    Stick a webcam and some time lapse software on it, then spend ages noting down what it is doing.

    Shame that the meter makers don't have an output that is easy to use.
    :sad:
    • CommentAuthorSprocket
    • CommentTimeJun 8th 2012
     
    OK, so it's (unfortunately) looking increasingly likely that the "OpenEnergyMonitor" hardware (or something more homebrew) is the only feasible solution. I note that they recently looked an ATMEL application note that would deal nicely with the "precision at low consumption" issue. Unfortunately that approach will probably will have to wait until I retire unless they make it soon but it looks promising.

    Same problem for me though... what is the best kit that I can buy right now that will get me 3-phase data recording and network connectivity.

    emoncms looks good but the physical hookup requires a bit of effort that I would like to simplify.
    • CommentAuthorSprocket
    • CommentTimeJun 9th 2012
     
    I found this

    http://www.logicbeach.com/sensors/Modbus_Power_Transducers.html

    not cheap though and onlyavailable in US :-/
    If anyone knows of anything similar, cheaper, from Europe please shout.
    • CommentAuthorSprocket
    • CommentTimeJun 9th 2012
     
    Never mind, I found this now... looks much more like what I need

    http://www.elkor.net/WattsOn.htm

    I notice it is also called a "WattsOn" but I don't know if it has any connection with the Wattson devices mentioned above.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 9th 2012
     
    Get Paul in Montreal to check it out as they are in his neck of the woods, kind of.
    • CommentAuthorJoiner
    • CommentTimeJun 9th 2012
     
    There's a pdf with technical specs here.. .http://www.elkor.net/products_all.htm
    • CommentAuthorSprocket
    • CommentTimeJun 9th 2012
     
    I've emailed to ask for a price.
    However in the meantime I also found the Socomec Countis E53 here:-

    http://www.socomec.com/documentation-retrofit-line_en.html
    Available at £100 at SHM Meter Shop in the UK. Sounds like a good price. Has a display and does import/export too!

    And I found this Hioneywell thing but no obvious supplier:-
    http://beyondinnovation.honeywell.com/reference_materials/submeters/install/63_1339_sxb_modbus_rtu_spec_data.pdf

    I don't know why but I suspect the Elkor box is expensive. I'm not sure that the benefit over the Socomec is worthwhile though. I'll report back when I have a price.
    • CommentAuthorjms452
    • CommentTimeJun 10th 2012
     
    I'll give the wattson solar plus a go and report back.

    Thanks for all your help

    J
    • CommentAuthorSprocket
    • CommentTimeJun 11th 2012
     
    Damon said

    > I haven't seen ANY clamp solution accurately measuring generation by my PV system

    I missed that comment first time around.
    That's a good point. To work properly it would have to track and measure the whole waveform, not just an average.

    Even if I find something else that shows some numbers it'll be hard to know if it is correct unless the manufacturer declares it is good for solar (like the Wattson solar that jms is trying). I suppose I could hang it on the inverter outputs first and see if it matches the generation meter and inverter numbers.

    At least with the Open Energy Monitor you can see what it is doing and have some confidence.
    I think maybe I should try OEM as well as a commercial solution.
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 11th 2012
     
    And track the whole waveform *relative* to voltage.

    I theoretically have a hardware solution actually installed, but have never actually got at round tuit, annoyingly.

    Rgds

    Damon
    • CommentAuthorjms452
    • CommentTimeJun 11th 2012
     
    our old OWL gave a fairly good agreement with with the generation - baseload (just couldn't cope with exporting)so unless the Wattson is any worse it should ok.

    I'm not sure what inverter(s) you have Damon but the 3600TLV-20 manual says cos theta = 1 which should mean it will work OK with current clamps (subject to waveform). It also appears to disconnect itself when not generating (presumably to meet the claim of <0.5W night usage) so phantom night usage/generation should be minimised.
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 11th 2012
     
    I have 4x SMA Sunny Boy G83-compliant inverters, so presumably sane as regards theta, etc.

    I observe that every current clamp measures generation from them very very badly, especially at the low end.

    The empirical difference between theory and practice!

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 11th 2012
     
    Damon
    Which models?
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 11th 2012
     
    3xSB1100 and 1xSB1200: Claudia Schiffer wouldn't get out of bed for less than 10,000kWh...

    Rgds

    Damon
    • CommentAuthorbillt
    • CommentTimeJun 11th 2012
     
    Seems to be a bit of confusion here, blaming current transformers for the poor performance of simple, cheap whole house monitoring devices. Current transformers are linear devices, and can be quite accurate and read down to low powers. If you measure the voltage and phase as well as the current you can get accurate results with them.

    The input of my Brultech ECM1240, which is monitoring the SB3800 ouput among other things, tracks the inverters output readings well. One of the other inputs is tracking when a 3 watt fan switches on and off
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 11th 2012
     
    Posted By: DamonHDClaudia Schiffer wouldn't get out of bed for less than 10,000kWh

    Is her manager called Joules :wink:
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 11th 2012
     
    billt: if you read other recent threads the problem is that they generally *do not* read voltage and thus have at least two huge sources of error (actual voltage and phase vs current) swamping any precision problems in the current measurement, which I note to be large in practice for the various clamps I have tried and with my PV.

    Rgds

    Damon

    PS. ST: Watt? Is it a lack of energy or she powerless to resist?
  30.  
    I've been using a Wattson Solar Plus since the beginning of the year, and like it. I haven't checked for its accuracy - as mainly I use it as a visual alert that tells me when I'm exporting and it's a good time to put on the washing machine. Review available here: http://www.yougen.co.uk/blog-entry/1894/Wattson+Solar+Plus+helps+me+to+get+the+most+out+of+my+solar+PV/. A further review on the Holmes software that comes with it will follow soon.

1 to 30 of 43

  1. <
  2. 1
  3. 2
  4. >
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press