Domestic appliance power profile

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  • Morning all. I've got 2 Espruino devices mounted on my house meter and a solar meter so I can compare solar generation to house meter consumption. The solution simply counts the flashes on both meters.

    I want to understand a bit more about when I am exporting (giving it away). It's easy to establish consumption versus generation/import when the house meter is reading something (ie blue+red) but when there is no blue bar I don't know whether I'm balanced or exporting.

    You can see in the attached graph that there are a few 5 minute bloacks where I may be exporting and a few where I'm pretty close to being balanced.
    The blue is the house meter and the red is solar. I can't do a great deal with the blue peaks as they are washing machine peaks (2kw) versus a total of ~700w for the solar panels.

    Other than an export meter does anyone have any ideas about I how I can understand / avoid exporting.


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  • Sorry for the delay replying here...

    If your meter doesn't show you in any way, I guess your only way to be 100% sure about how much you're exporting is to put a clamp (CT?) meter onto the wire into your house. I think there are some DIY options around (like­te-raspberry-pi-power-monitoring-system/­) or you can get some with RS485/serial output.

    The Pi option linked might be cool as I guess you could clamp a bunch of different wires (solar, grid, house, even certain mains circuits)

    In terms of avoiding exporting, I know you can get immersion controllers that use a clamp meter to turn on the hot water immersion when there's too much solar power, that seems to be a good use.

    Or there are always battery packs. I've actually just invested in some solar panels and a bunch of cheap LiFePO4 rack batteries, so in a few months I might have some more thoughts about how worthwhile that is!

  • Great thanks @Gordon.

    I'd be really interested to hear about your solar/battery setup once you get some ideas.

    I've got micro inverters so the solar just dumps into my household supply. I don't have much excess in terms of wattage but it all adds up.

    I'm currently plotting a passive heat exchange in the loft - pipework in the loft to be heated by the sun and circulated/pumped (solar) into a small tank (I don't have an immersion) so water going into the combi boiler will be hotter to reduce the energy required to get it up to temperature.

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Domestic appliance power profile

Posted by Avatar for user121340 @user121340