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3 months since PTO: Pleasantly surprised by system output vs initial expectations. Pointless nerd stuff inside.

run-the-joules

Turgid Member
Aug 13, 2017
3,785
7,350
SF Bay
TL;DR: Solar rules. Get on it.




Background: Got my 8.1kw system installed a few months ago (very smooth process, only took a few weeks if you ignore the times where *I* was the holdup), with PTO in early December. I put on as big of a system as I could reasonably fit, with the goal of minimizing how much money I give to PG&E in the short term, and profiting in the long term.


solar-layout copy.jpg


IMG_7623.jpg



My overall goal is to be able to average around 28kWh per day for the year, which "should" cover my usage completely other than NBCs. All of December had me getting at best around 18kWh per day, which had me a little worried. However, I knew that these numbers were about as bad as it'd get, with the short days, bad angles, and the neighbor's house cutting off my late afternoon production with the low winter sun.

Here was a typical December day for me:
IMG_0FC34BFD78FC-1.jpeg


As winter went on, I was less and less convinced that I should switch to a heat pump when I get my HVAC system replaced in the next couple of months, with how little power I was generating in the winter, and with the amount of heat that I thought the house was using to stay warm. Then I realized I had insight into that data, too, and almost all of our gas heating happens off-peak.

1615237791593.png


Hey, good news! Maybe a heat pump makes sense after all, but what about my system production?


Well, as the days get longer and as the angles of the sun begin to move towards what my system has been waiting for, the numbers and the curves are looking one hell of a lot better. I saw my first day over 30kWh by the last week of February, and now I find myself genuinely curious to see what the real peak of my system will be.



IMG_EA9607D3490B-1.jpeg




I'm also monitoring a wide variety of things for my system and house in general, and despite not having a powerwall or neurio, I'm able to monitor my grid power consumption with a rainforest eagle 200.


On February 23rd, I was almost perfectly at 50% net grid consumption since bringing the Eagle online:

1615237296444.png




Just three short weeks later, I'm down to 39% net grid consumption:

1615237412594.png



At this rate, things are looking really good and I'm thrilled with the system. I do wish I could add a powerwall or two, but right now with demand and prices so high, I'm not really enthusiastic about the cost vs benefit. I remain somewhat hopeful that the third-gen powerwall will come out once they're not as battery-constrained as they are right now, with higher capacity and/or lower costs to reflect improvements in technology (in terms of $/kWh, the powerwall is DRAMATICALLY more expensive than the cars!)

So… yeah. Kinda pointless post, but wanted to share.
 
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run-the-joules

Turgid Member
Aug 13, 2017
3,785
7,350
SF Bay
you have a really steep production curve. do the other houses shade you during morning and late afternoon?


In the mornings, there's a hill and trees to the north/east that might shade a bit, though I'd have to actually get out of bed early enough to look and see if that's affecting things.

In the afternoons a couple of months ago, I'd catch some late afternoon shade from the house to the southwest of me, but my chimney also contributes to that, I believe. I need to get off my ass and start looking at the per-panel data and building a model to see what time each panel starts waking up and going back to sleep.

Additionally, my roof is pretty steep apparently.

Also, the graph auto-scales so that might be causing some confusion. Lemme scale things out to put them to the same relative metric and re-post, sit tight.
 
Last edited:
Which app are the screenshots for consumption from? Looks very nice. I also did not get Powerblaster and even though I have Vue, I cannot get production and consumption in the same app.

On the batteries, I don't think they are worth it, except for back up and even then I'd rather try some portable battery from HD first.

I got a PTO on the same size system in late January and I am seeing so much production, I think I need to get a heat pump. But they are very expensive, at least the quiet ones. I am going to run more AC this summer hoping it breaks.
 

run-the-joules

Turgid Member
Aug 13, 2017
3,785
7,350
SF Bay
Which app are the screenshots for consumption from? Looks very nice. I also did not get Powerblaster and even though I have Vue, I cannot get production and consumption in the same app.

On the batteries, I don't think they are worth it, except for back up and even then I'd rather try some portable battery from HD first.

I got a PTO on the same size system in late January and I am seeing so much production, I think I need to get a heat pump. But they are very expensive, at least the quiet ones. I am going to run more AC this summer hoping it breaks.

I'm using Home Assistant and doing a bit of back-end math to figure out consumption. Basically I have a synthetic "sensor" reading that is calculated as a function of the grid power flow and the solar production. Sometimes it's a little bit off though because of the difference in refresh rates using the SolarEdge API vs the Eagle. At some point I'm gonna try and set up Modbus TCP on the solaredge inverter and get realtime data with MQTT.
 

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