Question for the Solar Guru's... 🌞

[Haydn12]

We have 14.4 KWh system - 36 REC Pure Alpha panels. This has been generating at it peak about 10.5 KWh and almost 90 KWh on a clear day at this time of year. We have 2 FranklinWH batteries (27.2 KWh). We have been using very little power from the grid and we are charging both a MachE and an Ioniq 6. My wife drives 110 miles round trip for work. So the solar has been great so far!

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[doogie63]

How much do you pay for per kwh? I only pay .09 which for my area would take forever to make my money back for solar. The neighbor is learning the hard way. He now pays more per month with the finance and power. Power is down some but with the new finance more then he was paying. Another friend in another states pays .35 the cheapest for kwh so solar is working for him

 

[watchdoc]

We have 14.4 KWh system - 36 REC Pure Alpha panels. This has been generating at it peak about 10.5 KWh and almost 90 KWh on a clear day at this time of year. We have 2 FranklinWH batteries (27.2 KWh). We have been using very little power from the grid and we are charging both a MachE and an Ioniq 6. My wife drives 110 miles round trip for work. So the solar has been great so far!

90kWh out of 14.4 panels is excellent. I'm guessing you have Enphase microinverters and AC coupled Franklins?

 

[dalola]

How much do you pay for per kwh? I only pay .09 which for my area would take forever to make my money back for solar. The neighbor is learning the hard way. He now pays more per month with the finance and power. Power is down some but with the new finance more then he was paying. Another friend in another states pays .35 the cheapest for kwh so solar is working for him

Yeah, for sure that's all part of the feasibility process.... my current rate is $.15/kWh, so I'll have to carefully look at my ROI on different options.... If I can keep my average monthly payment fairly equal, solar vs grid, that will probably be my primary deciding factor.

 

[markboris]

Well, since everyone is sharing bits and pieces of their systems.. this is what mine produces for one day during the summer, full sun

During the winter full sun

And when it’s cloudy and raining all day

 

[dalola]

Mark, in an average year, are you overall selling more power than you are buying?

 

[markboris]

Mark, in an average year, are you overall selling more power than you are buying?

Yes but only because I have 4 Powerwalls. Even with the solar I produce, I use quite a bit of power. During the summer, temps are over 100 for at least 2 months. Nights don't cool down any lower than 88 so AC (3 units) are on 24/7 plus hot tub, Mach-E, etc. Not until I got the Powerwalls did I start to have a credit on my true up at the end of the year. They run the entire house anytime there is no solar production. I rarely have to use any power from the utility company ( a couple of times a year and only in the winter) but even if I do, I still have a $400-$1200 credit at true up. Because they (PG&E) won't cut me a check, a couple of months before true up, I shut down the batteries and try to use up all my credit so they don't get my power for free.

 

[Tosh]

I agree the battery storage addition is the way to go now. Panel efficiency is way up in the last decade, you can't use everything you produce, and the grid wants more storage!

Truth be told, I'm too old to think of ROI in my solar investment. However, my grandkids might thank me for it.

 

[Booradley]

Solar typically is something that needs permits. In my area the county controls the physical and mechanical aspects to ensure the system will handle wind, snow loading ing. And the roof structure is correct. The electric company controls the electrical requirements for grid tie and net metering. The process of permitting is basically a plan that satisfies these entities. A solar company would charge for the permitting. There’s more to it than I mentioned but that’s basically what is required.

 

[Chrisbriding]

Just another thing to consider when selecting an installer for solar; our installer guaranteed a certain level of production for a specific time period (years). If the system does not perform as guaranteed, they are on the hook to come out and install more panels. We do not have storage.

Can you tell when we got the Mach-e?

 

[Rick65]

see how good your roof location is for solar https://sunroof.withgoogle.com/

 

[knemchak]

Yeah, for sure that's all part of the feasibility process.... my current rate is $.15/kWh, so I'll have to carefully look at my ROI on different options.... If I can keep my average monthly payment fairly equal, solar vs grid, that will probably be my primary deciding factor.

Also, take into account degradation of the system over time.

 

[Nikos]

Is there some kind of a rough conversion for square feet of roof space as it relates to potential energy capture? I've got about 600ft2 of 6/12 south-facing roof on the back of my garage, I'm considering a solar installation up there, primarily to provide power for my Emporium charger, plus any left over to feed into the house/garage. Any thoughts/comments from those who have experience with solar?

I have the solar set up with storage batteries and an interconnection agreement.
Solar panels for more than 3 1/2 years and batteries for almost 3 years.
Your reputable installer has an engineer who will make a mapping of your roof, the angle of the sun hitting your panels and the actual utilization of the sun every day. That means, how many hours per day your panels will see the sun, from sunrise to sundown.
No matter if the sun is hitting your panels, unless the sun is directly overhead at 0deg relative to your panels, that would be the only time your panels will maximize output. That would be only about 1 hour. All the other hours of the day, the sun will be at a different angle relative of your panels.
Another thing to consider, when the sun is directly overhead and at 0deg, the panels will get hot, very hot, and the efficiency converting sunlight will drop or flatten out.
Let say your system is a 9 KW with some panels pointing S-SW and some pointing W at a high pitch rooof, you will not see 9KW produced every hour.
That is the nature of the beast. Unless you have your solar panels following the sun, which complicates the system a lot.
I run a system with 28 375W panels.
18 panels point SW and 10 point W. In the spring and summer, I get roughly 8 hours of sun. My best production days are in the spring were the trees don’t have leaves yet in large numbers. My best production days are in February, March, April and May. 45KW is my daily maximum.
Enphase micro inverters. Enphase storage batteries and Enphase monitoring system. An interconnection system with Duke Energy if you want to sell your excess power to the grid.
I have tried all kinds of combinations of how to utilize my solar production to my advantage and here is what is working and not working.
If you going to have an interconnection agreement, ( you need that if you going to sell the excess to your utility), is best not to use your solar solar production to charge your vehicle because won’t be enough of an amperage to make a dent to charge your EV. Forget about any excess. Won’t be any. You actually going to utilize the grid 95% of the time. Also your interconnection agreement will show you and indicate if you have a Net Metering contract and kind of Net Metering agreement your power utility will allow you to operate under.
Enphase App tells me what is my production, consumption of my battery system and the grid. If your interconnection agreement allows you to total your entire production of the day, that is 24 hours, versus your daily consumption of your house, then you do the math. Solar production in 24 hours is 40KW and your house consumed 25KW thru out a 24 hour period then your excess is 15KW you give to the grid. Depending on your contract with your utility you will figure the amount of compensation. Usually the utilities tally the consumption on a weekly or monthly basis.
Depending of what system you going to install, solar or solar and battery, you will find that trying to keep up with charging your EV with your solar panels is futile endeavor. I don’t want to disappoint you but I have tried every angle possible. My Net Metering agreement is generous. Not Al Net Metering agreements are the same and vary considerably from state to state, region by region.
First have your installer map your roof, determine the sun’s angle to your roof, and set up the utility permits and agreements. Without an interconnection agreement from your utility and basically you’re not going to put nothing on your roof. No agreement, no tying to the grid.
Now you will find how receptive your power utility is to putting solar panels on your roof.
Good luck. Don’t give up. Look into it first and don’t take your installer’s word that everything will work out.

 

[Bakahump]

Keep in mind that systems are DC. So like in my case I have 30x400 watts for a ”12kw” system. Let’s talk about what that means. In. PERFECT world (which you will NOT get) it means that your system would produce 12000 watts DC every hour of those perfect conditions. At sat “50%” of perfect (clouds or close to dawn or twilight for examples) you would produce 6000w DC. It’s important t to differentiate DC from what you “actually get” from AC. In my case in the BEST REAL WORLD conditions I get 9.6kw per hour in AC power. So over the course of a 10-12 hour beautiful day I might generate 65kw AC.
so whether you use Net metering or battery your gonna need to store your excess power you create at 1pm for 11pm usage. Net metering (which in my case is a 1 for 1 trade of whatever I produce for when I need it) is the cheapest. Battery’s of course are additional costs during install. Plus I doubt you are truly going off grid so anything you don’t produce (but do use) can be purchased at market rate from you power supplier. Not ideal but also not the end of the world (esp as related EVs). For instance in Maine a kWh is about $.25. That’s expensive (like top 10 nationally). If your like 12 or.15 cents from the power company then needing to buy an extra 50 or 100 is not the end of the world.
Like many above my 12 kw (again DC) system was pretty “under powered” in Dec/jan/feb using heat pumps (heat and hot water) regular “house stuff” (cooking dryer) and the Ev charging.
But a big thing to keep in mind is that solar is a marathon, not a sprint .

you DO not want to produce 3000kwh in Jan (which would cover you 100%) and then be paying for that same system in July when you producing 9237kwh and only using 2000 or 4000. The goal is a balance. Yup I was short in Jan by 1000 but I was +475 in jun and July and Aug. which made up for my winter shortage.

in my case I added a little to my household needs bought a solar system THEN bought an EV. Which (at least while the kids are home using more electricity) has kept me in a slight negative. You are at least smart enough to look for solar after the ev. ?

PVwatts is a great tool but be sure to add 10% to what you THINK you need or so (imho) because I think even they are a bit optimistic. And I THINK that most retailers are optimistic “no we can keep you under 40k$ and cover all your needs!” When for 42 or 45k$ you actually could. So keep that in mind. But as I said EVEN if you do under produce a bit it’s not as bad as I think some of us make it out in our mind to be.

 

[Side Show Bob]

Thanks all, for the thoughts/info. So it seems very doable.... Next steps are to contact a local solar pro, to get specifics for my area. It's too much out of my wheelhouse for a DIY, other than maybe some of the install. But as far as the spec/set-up, I'll need help there for sure. I'll provide updates as I move along... but this is early early investigation phase..... ? Feel free anyone, to keep adding thoughts/comments/information....

I installed 24 panels with two batteries. This was three years ago. I chose SunPower .. Then they went bankrupt. So no more warranty. The solar panels are manufactured by Enphase, each has its own inverter . So the solar panels are still under parts only warranty.. The system works great. I had one issue with th batteries this last February and a guy on Redit helped me get them back on line. A simple power down and unplug wires and replug them in. So I am not sorry about installing solar with batteries. I just would do it differently. I looked into Germany and found out the cost of solar is almost half of what we pay in the USA. They have no middle men . It’s just an electrician installs the panels and system. So I would only install all parts that are made by a known manufacturer, Enphase, LG,etc. so you never lose your warranty on parts. I would look into having an electric Ian install the equipment and have a company like Enphase do the controller. Just my thoughts.

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