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diy solar

Off Grid Solar System, opinions and advice welcomed

Just over paneling all facing south (if your charge controller allows it) makes a huge difference. We went from about 6-8kWh in winter production to an average of 14.2kWh in Jan production so far by simply doubling our array size from 2565w to 5130w on a single midnite solar classic 150.
 
I just found this fourm so am going to be doing some digging around before I ask any more questions.

I've already ordered all the components mentioned above so am commited now.

I've got to wait until beginning March for the battery so i've got time to do more research.

I'm based in California at the moment, will be driving down to Oklahoma at the end of this month via Phoenix to pick up a pallet of solar panels (25) from santan solar. I promissed my neighbor who sold us the land I would bring him back some panels. I've just got to tell him now that we want half of them.
12 panels should be 2400w based on 80% efficiency.
 
MrM1 said:
Just over paneling all facing south (if your charge controller allows it) makes a huge difference. We went from about 6-8kWh in winter production to an average of 14.2kWh in Jan production so far by simply doubling our array size from 2565w to 5130w on a single midnite solar classic 150.
Click to expand...
Where abouts are you based? Do you know what your average kwh production was on your 2565w array during good solar conditions?

thanks
 
JamesHird said:
Where abouts are you based? Do you know what your average kwh production was on your 2565w array during good solar conditions?

thanks
Click to expand...
North Central FL

I've been at this for over 4 years now. 4000w Schneider Conext SW4024 and Midnite Solar Classic 150 System has worked flawlessly. (build is in my signature).

Before the array up grade the largest production I ever saw was a rare 12kWh ever once in a while in late spring or early fall on a perfect day. I used to keep a spread sheet of daily production for about 2 years. Averaged probably 9.5 per day in a year. Biggest daily max at any given moment I would see would be 2200 ish watts then it'd settle back down Around 2000-2100 on a great day

Since upgrading the array, now my average in Jan as of today is 13.8 (down a little Bc of 2 crap days). But I routinely seen the system clipping at 2480 ish from 11am to 3pm. And if I turn off the old or new array (each 3s3p), each array is producing a max of about 1900w at solar noon on a cloudless day in Jan.

The Midnite Solar class maxes out right at 2600w input total at 94 amps and 27.9 vdc charging volts, but I set it to limit out put to 88 amps because of heat. At 88 amps the FETs are at 72°c, at 94 amps the FETs are at 88°c +. Midnite solar says 72c is perfect.

Here is Dec before and after. New array went online Dec 18. The next 4 days were crap. Then we settled in a more typical weather pattern.

Capture+_2022-01-11-18-52-35~2.png
 
Long story short
-PV is cheap, at least cheaper than batteries
-some (not all) SCCs (solar charge controllers) and all in one's allow for over paneling . There is a resource down load here of which do and don't allow over paneling
-sadly, as best we can tell here from research and antidote evidence, the Growatts with transformers like the 12kw do not allow for over paneling

I am about to install a fully off grid 12kw Growatt inverter at my daughter's farm. No power there . Poco wanted $35k+ to bring lines out a 1/4 mile for the privilege of being charged monthly for power. We are building the system for just over $15k. Sig Solar told us we could install 11.8kw of array split into the 2 PV inputs. Then another member here smoked there scc over paneled and it appeared u can only do 7kw arrays split into 3500w + 3500w input into the Growatts.

Since Sig Solar had already sold us the 11.8kw of panels, so we decided to get a second scc and use the full array no clipping.
 
JamesHird said:
I just found this fourm so am going to be doing some digging around before I ask any more questions.

I've already ordered all the components mentioned above so am commited now.

I've got to wait until beginning March for the battery so i've got time to do more research.

I'm based in California at the moment, will be driving down to Oklahoma at the end of this month via Phoenix to pick up a pallet of solar panels (25) from santan solar. I promissed my neighbor who sold us the land I would bring him back some panels. I've just got to tell him now that we want half of them.
12 panels should be 2400w based on 80% efficiency.
Click to expand...

You can simulate your array performance based on location and weather here:

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations
pvwatts.nrel.gov pvwatts.nrel.gov

Here's a run for Altus, OK, 2400W, 30° tilt, south facing:


1641946267150.png


Divide the AC Energy number by the # of days in the month, and that's your daily kWh harvest., so Jan, 295/31 = 9.5kWh.

It does factor in average weather over the last 30 years for each day.

If you're feeling brave, you can download hourly data, which gives you an idea of how many consecutive days you might get poor charging.

This tool also has a simulator that can estimate how many days per year your battery will be tapped:

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

Photovoltaic Geographical Information System (PVGIS)
re.jrc.ec.europa.eu re.jrc.ec.europa.eu
 
MrM1 said:
North Central FL

I've been at this for over 4 years now. 4000w Schneider Conext SW4024 and Midnite Solar Classic 150 System has worked flawlessly. (build is in my signature).

Before the array up grade the largest production I ever saw was a rare 12kWh ever once in a while in late spring or early fall on a perfect day. I used to keep a spread sheet of daily production for about 2 years. Averaged probably 9.5 per day in a year. Biggest daily max at any given moment I would see would be 2200 ish watts then it'd settle back down Around 2000-2100 on a great day

Since upgrading the array, now my average in Jan as of today is 13.8 (down a little Bc of 2 crap days). But I routinely seen the system clipping at 2480 ish from 11am to 3pm. And if I turn off the old or new array (each 3s3p), each array is producing a max of about 1900w at solar noon on a cloudless day in Jan.

The Midnite Solar class maxes out right at 2600w input total at 94 amps and 27.9 vdc charging volts, but I set it to limit out put to 88 amps because of heat. At 88 amps the FETs are at 72°c, at 94 amps the FETs are at 88°c +. Midnite solar says 72c is perfect.

Here is Dec before and after. New array went online Dec 18. The next 4 days were crap. Then we settled in a more typical weather pattern.

View attachment 79277
Click to expand...
Nice, Thanks for the infomation.
My array will be a similar size to your original one so its nice to see your figures
 
sunshine_eggo said:
You can simulate your array performance based on location and weather here:

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations
pvwatts.nrel.gov pvwatts.nrel.gov

Here's a run for Altus, OK, 2400W, 30° tilt, south facing:


View attachment 79283


Divide the AC Energy number by the # of days in the month, and that's your daily kWh harvest., so Jan, 295/31 = 9.5kWh.

It does factor in average weather over the last 30 years for each day.

If you're feeling brave, you can download hourly data, which gives you an idea of how many consecutive days you might get poor charging.

This tool also has a simulator that can estimate how many days per year your battery will be tapped:

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

Photovoltaic Geographical Information System (PVGIS)
re.jrc.ec.europa.eu re.jrc.ec.europa.eu
Click to expand...

Nice, thank you.

so 3890/365 =10.65kwh per day on average

That seems good for our energy consumption needs.

If we were to do a 6s2p array. half facing SE half SW do you have any advice on how far off south we should have the panels facing? like SE and SW or SSE and SSW?
 
Link the inverter? All I can find is a link to the transformer.

But I would think your biggest issue to watch will b VOC, operating input volts at a specific system voltage, and not exceeding array input. At least not much. Different orientations will mitigate it some, and allow a little more over paneling
 
Can the SCC do 6s?I was only going to run our growatt 12kw 250voc on 4s or 192voc operating. 5s was getting me too close
 
James,
I would encourage you to not think too small. After all, solar is "free" after the first $25,000 LOL

I have spent right at 20k, but I have a beast of an 18 kw inverter that can handle 3X the rated surge current.
So I'm running a 2.5 ton central ac heat pump, water heater, freezer, fridge and large air compressor.

It may take you some time to build your system large enough, but why not ?
A freakin' cheap car costs more than my system. I say go big !
 
MrM1 said:
Link the inverter? All I can find is a link to the transformer.

But I would think your biggest issue to watch will b VOC, operating input volts at a specific system voltage, and not exceeding array input. At least not much. Different orientations will mitigate it some, and allow a little more over paneling
Click to expand...
Link to inverter/SCC

www.signaturesolar.com

5kW Stackable 5000ES (USA Model) 48V 240VAC 100A 450VDC Off-Grid Inver

Growatt 5000W Solar Inverter Charger With Built-in MPPT 100A Solar Battery Regulator DC 48V System Output AC 220V Max PV 500V off grid solar system on grid solar system solar grid off grid inverter off grid power systems on grid off grid sunny island inverter 10kw off grid solar system price off...
www.signaturesolar.com
 
MrM1 said:
Link the inverter? All I can find is a link to the transformer.

But I would think your biggest issue to watch will b VOC, operating input volts at a specific system voltage, and not exceeding array input. At least not much. Different orientations will mitigate it some, and allow a little more over panel
Click to expand...

450VOC
 
MrM1 said:
Can the SCC do 6s?I was only going to run our growatt 12kw 250voc on 4s or 192voc operating. 5s was getting me too close
Click to expand...
as I understand it 6s of my panels at 37.6 V per panel is 225.6VOC
The charge controller is rated at 450VOC max so well under
 
BMcL said:
James,
I would encourage you to not think too small. After all, solar is "free" after the first $25,000 LOL

I have spent right at 20k, but I have a beast of an 18 kw inverter that can handle 3X the rated surge current.
So I'm running a 2.5 ton central ac heat pump, water heater, freezer, fridge and large air compressor.

It may take you some time to build your system large enough, but why not ?
A freakin' cheap car costs more than my system. I say go big !
Click to expand...
Go big or go home! hahaha

This is just the start for our system. We'll probably spend around $4000 on this begining stage.

Once the initial development stage of our homestead is complete and I can dedicate some time to making money and not spending it we will upgrade. I see us spending $15,000 total and we should be good.

I'm doing the whole build myself so got my hands full. Going down end of Jan to start clearing. my neigbours got a bobcat so clearing 2 acres and building roads first. Then throwing up a couple of temporery structures and getting our water sorted.

getting all the solar components begining of March so will be a big relief from living off a generator for a couple of months
 
"water pumps 120wh"

That sounds like a small booster pump, but no well pump.
 
Hedges said:
"water pumps 120wh"

That sounds like a small booster pump, but no well pump.
Click to expand...
Yeah no well pump at the moment. We are fortunate enough to have good neigbours who allow us to use ther well for the time being. We have an ICB tote on a flatbed trailer for transporting the water from there well head

The 120wh estimate is for pumping the water into the holding tank in our 5th wheel from an ICB tote and the 12v pumps in the 5th wheel that supply the faucets and shower

All he irrigation will be gravity fed rainwater
 
JamesHird said:
Nice, thank you.

so 3890/365 =10.65kwh per day on average
Click to expand...

True, but summer/winter daily averages will be closer to 8.5 and summer closer to 11.5.


JamesHird said:
That seems good for our energy consumption needs.

If we were to do a 6s2p array. half facing SE half SW do you have any advice on how far off south we should have the panels facing? like SE and SW or SSE and SSW?
Click to expand...

With the assumptions I made on the array so far (location and tilt), and picking some good days in June and Dec, the difference in yield at earlier/later hours really doesn't warrant splitting the array unless you go to extremes (east and west facing only), and those extremes really impact the total power production.

Best results will be had by a single optimal array. You'll just need to be diligent exploiting your peak solar in the middle of the day.
 
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