Image is a graph from the electric company showing my usage for a day this week. From 6:30 AM to 8:30 PM we used absolutely no utility power.

I’m almost at the three week mark for having this system up and running. The first two weeks I only had 3 KW of PV input but I added another 5 panels to bring it up to 4 KW last week. It’s also still running from a transfer switch in “off grid” mode because I don’t yet have the prep work done to move my breaker box and start moving circuits to it. (That means I’m either on full solar+battery or utility, no mixing or load sharing).

Once I get it wired in fully, I’m probably going to switch to time-of-use billing. Unfortunately, I can’t do that ahead of time because rather than just making off-peak use cheaper, it makes peak usage (M-F 7am to 9pm) extremely expensive while off peak dirt cheap. I wish there was a middle option, but it is what it is.

I’m also being very conservative with my battery usage since I want to have at least 50% in “reserve” to cover power outages. That’s especially important during these heat waves. We could easily run 24/7 but would have to take a day off every so often to just let it charge back up since my system is a bit too small to cover all our usage indefinitely (at least if we want to run the A/C for comfort, that is).

  • Schwim Dandy@piefed.zipEnglish
    6·
    8 hours ago

    Can i ask what you’re using to monitor your usage? Is it something installed in the panel to detect wattage?

    • Iced Raktajino@startrek.websiteOPEnglish
      7·
      8 hours ago

      The graph displayed is from the power company website. It’s showing the power I use from them (uploaded from the smart meter). The relevant bit there is the negative space where I’m not using any utility power.

      For local monitoring of the PV system, I don’t have anything yet except for the counters displayed on its LCD (see below).

      The inverter has a smartphone app and wifi-module but that requires creating an account and letting it upload stats to a 3rd party server which I will never allow. However, it also has a serial port and speaks the Modbus protocol, and it’s pretty well documented.

      There’s a HomeAssistant plugin (ha-solarman) that I’m going to setup when I have time. That’ll pipe the inverter stats to a HA dashboard and can also let me change some of the config options from there instead of having to go to the inverter’s panel and set individual parameters.

      Sorry it’s blurry, but had to snap it quick since the display runs in kind of a carousel between different values. It’s showing here that I’m getting 2.3 KW from PV right now, one phase of the output is 0.1 KW (the other is 0.9 KW; it displays them separately), the battery is at 53.6 volts and is being charged, and I’ve generated 267.3 KWh since I installed it. The utility input is disconnected so there’s no arrows coming from it.

      • Schwim Dandy@piefed.zipEnglish
        5·
        7 hours ago

        Thanks very much for the detailed info. It seems Europe is much more friendly about providing info to the customer. The US allows our power cos to keep a lot of the data under wraps. Solarman looks like a great set of products but is sadly eu-centric.

        • Iced Raktajino@startrek.websiteOPEnglish
          7·
          6 hours ago

          I’m in the US, lol, just not in a very solar-friendly area. The power company data I have access to is a side effect of both their green washing and constantly rising rates. It’s supposed to help you manage your bill more than anything else.

          The batteries and inverter I’m using are Eco-Worthy which is Chinese and available globally. The inverter itself is a re-badged SRNE and has proven to be reliable and well built. Not sure if they’ve passed EU certification, but they’re UL9540 and UL1973 certified in the US

          The HomeAssistant module was made for Solarman products but is compatible with others such as the inverter I have (which is itself a re-badged SRNE one).