@ksmithaz1 do you have a set goal for battery storage in mind? That sounds like a good bit of panels, if I’m reading correctly and you had double the bank would you make it through the nights/weekends and be fine to top the batteries still as well?
Get a big battery
- Thread starter Zwy
- Start date
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
18kw panels - 200Kwh batteries. So 11:1?
If I truly drain my battery I can’t fully recharge in a day.
I have about 3 days of zero charging before have to break out Generator.
Been using right what I have been producing each day. 70-90Kw each day but as the days get shorter the less I bring in.
Since I got the 15kw inverters I can now double my array size.
That’s what I’m doing now.
Hopefully can get it done before it gets to cold.
Then I will be 36kw Panels- 200Kwh batteries 5.5:1 after.
DougfromdaUP
Solar Enthusiast
10.3 kW panels, 25.6 kWh batteries for 2.5:1. Not enough of either one, although I haven’t bought from the utility since June 5th (but I just flipped the breaker On today.)
I just got the next 4400 watts of panels but not sure they’ll get up before winter.
I just got the next 4400 watts of panels but not sure they’ll get up before winter.
ksmithaz1
Solar / EV Junkie
Mostly,
Not really on the weekends. Likely not at all in summer. The CS 250's (in the sig below) is down to 15. One of the panels was causing grief in the string I finally isolated and removed it. I plumbed for all 6 strings to the inverters. I can reconfigure a bit as needed each AIO will handle 500+v strings. I currently have the roof array at 4x8 and the ground at 2x7,8 for balance between the inverters, but there is no reason I couldn't easily change it to 3x10,10,12, and pump another 12 450ish watt panels on the roof, then put another 12 or so on an outbuilding. At that point I might just dump the CS250 ground array. Some of the Solar outfits have used 350's at about 0.30/kw or less, those are also a bit smaller. Some of these new panels are huge like 86x45. Starts to get hard to manage. I picked up the 250's for next to nothing, as extra overhead for charging the car. They take up a lot of real estate for their output.
ksmithaz1
Solar / EV Junkie
200kwh of batteries is very expensive. Overpaneling is often less expensive if you have the real estate to mount it. Then again if you have true zero output days, it doesn't matter how many panels you have. If you live in an area with very little sunshine solar does not seem like a practical solution for power to me. $60,000+ will buy a lot of grid-juice.
ksmithaz1
Solar / EV Junkie
Yea, you have to hit your extremes. Less sun = more panels. From a solar perspective Phoenix is pretty much ideal. In the winter, output goes down, but electric usage plummets even faster along side. Oddly though there are interesting thresholds with PV, because your demand curves are generally more consistent than your PV output. Thus you may find that since all your additional solar capacity now goes to your storage system it stays topped off, and isn't needed until later in the day, and stops discharging earlier. You shall see
!
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
The batteries were not $60k.
Total cost about 60K.
Even with the current rates I pay it was 10 years payback.
I did all the work myself.
I got 4 X 20kwh of some big old global power 400ah batteries in barter.
115kwh were DIY.
I bought 75kwh of SOK from Current Connected in case my DIY crapped out which hasn’t happened yet.
So technically I have 270Kwh.
More panels is definitely more cost effective.
Have to modify my Sinclair rack every time I add panels. Add another post and 3 Z Purlins and move my Cantilevers to the end.
Have plenty of land but if I put the array in the very best spot it would be 800-1000 Feet from the inverter building and be in the middle of the grassed area.
Wife wasn’t having that.
Our house sits at the very back of the property.
Barns, houses, neighbors 80 Ft Pine trees, my own trees, outbuildings.
I mapped it out for the best spot closest to the inverters and still 200 feet.
Did it more for the shit days then anything.
I can go 3 days on all electric house with Zero charging.
At least I can always add more panels now and not worry about batteries.
I wanted off the Grid.
Raising rates, unstable, subject to stupid rules.
Independence is worth it to me.
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chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,281
For RV: 1 kw panel to 5 kWw battery
For a portable generator: 1kw of panel to 1 kWh of battery
My panel to battery ratio really depends on my goals, and has been tested for real production, and van be seasonal.
For my RV, I have through trial and error decided that 5 kWh of battery works to 1 kw of panels with the goal of 2 days power.
For my portable generator it’s close to 1 kWh battery to 1 kw solar to produce about 300 watts of power with the goal of pulling from the battery as little as possible, and only use when the sun is shining. The panels are divided into 3 arrays for east, south and west coverage.
For a portable generator: 1kw of panel to 1 kWh of battery
My panel to battery ratio really depends on my goals, and has been tested for real production, and van be seasonal.
For my RV, I have through trial and error decided that 5 kWh of battery works to 1 kw of panels with the goal of 2 days power.
For my portable generator it’s close to 1 kWh battery to 1 kw solar to produce about 300 watts of power with the goal of pulling from the battery as little as possible, and only use when the sun is shining. The panels are divided into 3 arrays for east, south and west coverage.
OffGridForGood
Catch, make or grow everything you can.
Tilted up all my arrays today,
Doing a bit of a test: one array at 60, 65 and 70 degrees each - now we will see how they do over the next couple months. Not identical situation for each but close enough I think to see what happens.
I noticed last winter the steeper the better. I think this is due to the fact the sun rising starts on the horizon ie 0-degrees and comes up to the max azimuth by local noon, then drops again. So setting the panels at the correct angle for solar noon makes no sense really, the sun spends more time at lower angles than this during the short winter days. Besides, steeper is easier to clear snow, sometimes it is self-cleaning.
Doing a bit of a test: one array at 60, 65 and 70 degrees each - now we will see how they do over the next couple months. Not identical situation for each but close enough I think to see what happens.
I noticed last winter the steeper the better. I think this is due to the fact the sun rising starts on the horizon ie 0-degrees and comes up to the max azimuth by local noon, then drops again. So setting the panels at the correct angle for solar noon makes no sense really, the sun spends more time at lower angles than this during the short winter days. Besides, steeper is easier to clear snow, sometimes it is self-cleaning.
Zwy
Emperor Of Solar
Limited sun came out around 11 AM. Mostly cloudy but did get to 40% by 1 pm. I turned on the dishwasher since I reached 40% and let it run after lunch. Went out and cut down 3 trees. It actually turned to mostly clear skies but by 4 PM the clouds rolled back in heavy and no production. Ended up at 52% charge. Wife came home when I was cutting down trees. Later the wind died down and I went to burn brush and sharpen saws. Came in at 10 PM, she had decided to run the dryer and must have had about every electrical appliance on in the house. In less than 3 hours the battery dropped to 31%. Over 10 Kwh in 3 hours.
I am amazed by her ability to load the system down and really use up power.......
I am amazed by her ability to load the system down and really use up power.......
OffGridForGood
Catch, make or grow everything you can.
You have an Official Solar Tester too!
We need this, so we can learn from them, and build the systems up in some wild (misguided) attempt to be able to keep up!
Back a couple years, when we first got solar and batteries going, my wife asked if it was possible to collect solar from the long summers to heat the house all winter? - I told her we do that already, with firewood.
We need this, so we can learn from them, and build the systems up in some wild (misguided) attempt to be able to keep up!
Back a couple years, when we first got solar and batteries going, my wife asked if it was possible to collect solar from the long summers to heat the house all winter? - I told her we do that already, with firewood.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
OffGridForGood
Catch, make or grow everything you can.
It is All My Fault!
for 20-years I asked my wife 'can't the laundry be done in the evenings when the ToU rates are half price?
NOW...yeah, victim of my own success.
Quattrohead
Solar Wizard
OMG a new nickname for the ladies, Load Bank LOL
OffGridForGood
Catch, make or grow everything you can.
Sverige
A Brit in Sweden
I’ve got 8kWh of battery and 1.9kW of PV, so that’s what, just over 4:1.
OffGridForGood
Catch, make or grow everything you can.
and are you happy with this ratio?, or do you feel you need more battery or PV to be a better 'balance' if there is such a thing.
Reading over all the replies, it seems to be 5:1 - 6:1 range is where we are converging.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,912
1.5:1
But AGM, 1:1 usable.
Set to charge at 0.2C
This is grid-backup, and power failures more likely in the summer.
Works nicely in the day time, A/C and anything else powered by surplus PV.
Heat is switchable electric (net metering) or gas. On occasion I've awakened to find batteries powering the electric furnace - that would only run an hour.
It would work better if ridiculous loads were shed the moment grid went down, and some loads shed at night.
But AGM, 1:1 usable.
Set to charge at 0.2C
This is grid-backup, and power failures more likely in the summer.
Works nicely in the day time, A/C and anything else powered by surplus PV.
Heat is switchable electric (net metering) or gas. On occasion I've awakened to find batteries powering the electric furnace - that would only run an hour.
It would work better if ridiculous loads were shed the moment grid went down, and some loads shed at night.
