New US install w/ 19.2kW solar

Got an IoTaWatt a few weeks ago and am super impressed with the hardware, software, and community behind it. For my install, I added a 2" conduit in the bottom right of my breaker box to poke through the other side of the wall which is in a closet. I added an Orbit sprinkler box with the cheap GFCI outlet swapped for a normal decorator duplex outlet. Makes for quite the tidy install.


I purchased enough CTs to use all the channels. Currently monitoring both mains, solar backfeed (top left breaker), a subpanel to a shop (top right breaker), and various high-use applicances and rooms. I see several people using one CT to monitor solar - however I have a neutral on my backfeed and am using two CTs in case the legs are uneven, but I’ve never seen them vary by more than a few watts. Maybe I can repurpose one of those CTs somewhere else.

I have generation, consumption, and voltage uploading to PVOutput.org. Hope to set up emoncms on a local pi soon.

I plan on using this to monitor overall usage and see where I can shift that usage into the solar generation time since our net metering only pays for exported power at about half the rate of inported power.

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Welcome to the group and I’m jealous you have such a large solar array compared to my 7.3kw system. :slight_smile: What I do with all the energy credits for your system.

Nice install and i think you will find that PVOutput does a great job of overall check-in on your system and trending, etc. I like EmonCMS (Local) for more specific CT amounts and trends. As you said, it is a great group of people and the support from the creator is wonderful.

Hello quella - I think I actually read your review before purchasing the iotawatt and that sent me over the edge in deciding to buy it. No regrets at all.
Yeah, 19.2kW of solar is probably overkill…but I got a great deal on several new, old stock panels and inverters. I did the install myself which helped get the cost to about $0.85/W before any tax credit. It uses some older SMA string inverters, but honestly I think I prefer those to microinverters since I don’t have any shading issues where the panels are installed.

Glad to hear the review was helpful and I cannot speak enough to the great technology and support here for this tool.

Nice you were able to install the tech yourself. I would like to add a few panels later to another portion of the roof, but I would rather add a secondary battery to store my excess then generate too much. Are you doing EV cars or have a rather large home (or both) to have a 19k solar system?

I suppose our usage is decently high - I calculated needing a 12-14kW array to get us to net zero. With supplies being so cheap, I built as big as I could get approval from the electric company. We’re planning on adding on soon and my wife has thoughts of getting a Tesla cyber truck when they’re released, both of which would increase our usage.

Always nice to be as close to a bit over net neutral as one can. I would assume that any EV would add quite a bit and having more then one even more. Our system today was the max allowed based on our energy usage for the previous year. Our installers told us that if we were planning on getting EVs we or electric appliances, etc. we could note that and they would be able to build a bigger system. I would also assume there is a breakeven point as you do not want to many credits or not enough power. Thanks for the extra info.