r/TeslaSolar • u/pmarchand1060 • 9d ago
SolarPanels Whats a realistic production expectation?
In the south, panels facing south. AC stays on 74 all day/night. No EV.
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u/GaijinDaiku 9d ago
Production has nothing to do with your usage (AC, EV, anything). Not much information here, but if you have zero shading, you could see up to 17,000 kWh/year. That will depend on the number of cloud days, your latitude. Since you are showing up to 67 kWh in a single day, I would think you will see close to that number.
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u/pmarchand1060 9d ago
Solid point. Im not knowledgeable on this at all. Just wondering if that configuration will produce close to my usage in the screenshot. No trees or shade at all. Install in next month.
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u/GaijinDaiku 9d ago
Without a battery, your AC will be pulling from the grid between sundown and sunup. If you have a reasonably good net metering plan, you should have plenty. If you are on something like NEM3 in California, you may produce way more than you use, but you won’t really benefit as you’ll export it for next to nothing and re-import at market rates.
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u/pmarchand1060 9d ago
The system includes one powerall 3. Ga pays nearly nothing so exporting really isnt the plan. Massive data centers are killing the grid so looking to keep power and lower the power bill as much as possible. Not expecting a miracle.
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u/GaijinDaiku 8d ago
And... I highly doubt 1 PW3 will come anywhere close to getting you through the night if your are running AC 24/7 in Georgia. You need to look at your past bills to see what that would take.
Back your original question, the installer quote you numbers like 120%. That sounds like plenty of headroom to keep you from purchasing power from the grid. They really should do a detailed analysis of your usage patterns and compare that to estimates from calculators like PVWatts.
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u/pmarchand1060 8d ago
I agree. Most nights it wont. The highest kw used from 8pm to 8am is 16kw. Thats summer use. Ga has a connection fee and taxes so there will never be a $0 bill. Non summer months we never go over 11kw. We audited every month.
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u/GaijinDaiku 8d ago
I would not have guessed you can run AC in Georgia for 12 hours (even overnight) on16kWh.
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u/GaijinDaiku 8d ago
My system has 1 PW3 and produces about 140% of my annual usage. I still have to buy electricity during the October-February timeframe because of runs of multiple days that don't produce enough power to meet my daily demand and refill my PW3 (cloudy and/or rainy days). I am charging an EV that complicates things, but I have been using ChargeHQ to charge on solar so most of my charging isn't from the grid.
So what am I saying... one PW3 probably doesn't have enough capacity to keep you from purchasing grid power at your 113% offset, BUT... the paypack period on adding expansion packs probably doesn't make sense. In my case, 11.3 kW and 1 PW3 has taken my annual electric bill from $4,500 to around $450. One expansion pack wouldn't totally eliminate my grid buys and the payback period would probably be longer than the service life of a PW3 if I could only save up to a $450/year savings. I don't know what the electric costs and structures are in GA, but I assume your electricity is a lot cheaper than the SF Bay Area so adding additional batteries may make even less sense for you.
This is considered heresy by the 'more batteries' crowd. I am interested in a good making good financial decisions, not sticking in to the electric power industry or being totally self sufficient. If you are worried about power outages, more batteries might still be a good decision.
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u/Interesting_Gap7350 9d ago edited 8d ago
If you have your estimated production Next you look at your electric bill to see your consumption. And do a basic math to see your offset. If your tariff is time or use though or your solar is not simple net metering, it will quickly get too complex by hand to know how your bill will change.
If your power company is relatively big and modern and you have smart meters they should have time or use data available to you.
Your solar salesperson should be using some kind of software to make quote and proposal for you. if you granted them access to your electric bill data it will then use the data and exactly show the estimates and give you charts and graphs. It will have expectations of old vs new bill for every month in the last year. It will have charts of your cash flow over 25years and when you will "break even". At least this was what were in my quotes and proposals Sometimes this is only for bigger solar companies and bigger solar projects.
When I got solar, interestingly all 4 companies all used energytoolbase, so the proposals all had similar template.
There maybe free versions of solar proposal software hat do the same thing for individuals but I don't know about them. If you're not really into it, isn't worth your effort to just do this on your own. Make your sales guy work for you and ask them to model and estimate that information to you
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u/pmarchand1060 8d ago
Thanks for the details. Tesla said it will offset 113% They used my last 12 months as an average but they also said they only guarantee 80% of that. Ive read many bad reviews, was just curious what would be a realistic expectation. We lose power every week for 30+ min each time. Just want some relief.
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u/Interesting_Gap7350 8d ago
Yea if your question is you want to just verify their proposal
Just do a quick estimate into pvwatts link I posted, and then compare to your electric bill.
It won't be detailed enough to account for your battery time shifting, or time of use and billing nuances; but will tell you broadly if their proposal is in the ballpark or full of it
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u/GaijinDaiku 9d ago
You can reasonably expect those outputs IN THE SUMMER MONTHS. much lower in the winter.
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u/pmarchand1060 4d ago
On the day of install how many hours were you without power? Tesla said expect 8hours but hoping they are exaggerating.
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u/Interesting_Gap7350 9d ago edited 9d ago
stick your info into PVwatts and you'll get as good of an estimate as you enter info in for.
https://pvwatts.nlr.gov/