diy solar

diy solar

Solar house generator I started DIY back in 2000 - My path from Trace to Xantrex (on FLA battery) to XW Pro inverters on Tesla Model S batteries

I NOOOOOOOOOOD it!!!!! I had you pegged for that a long time ago Douglas, surprised it took you this long..... LOL
different issues, like paying off the ones I got, lol

I was surprised the improvement I got when I moved from 30 to 40 kwh of storage. Got me over the hump, at least for the summer, of avoiding GRID CONNECT events. April 28th to now, without a depleted battery is something big to me. Over time, adding 10 kwh per iteration will add up the storage. Next milestone is getting through the winter w/o a grid connect - well the amount of snow we get this coming winter may or may not be large, and will be a major factor in achieving that or not

If we are light on snow - more sun time - but water next year is going to be a bear.
 
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been sometime away

some progress and some backsteps and some healings in flight

here is a picture of my "corn patch" where I mounted 2 solar panel on south wall of shed

1880-watts-on-array-1-on-the-roof-jpg.43708


well as the sun got higher in the sky, the overhang shaded the panels so I laid out 2 355w panels on the ground against the wall of the shed

In the spring we planted sweet potatoes in the space left over. First time we did that and found out - they make lot of leaves
got back from 2 weeks of vacation and those 2 panels offline due shading

so I pondered a solution and decided to hang those panels via chains to the rafter.
Adjustable
Moveable
Versatile
and out of the leaf shade


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side view

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looking at a solution to tilt them but....

while on vacation my foot got infected again and I lost some tissue before I got some antibiotics and was under control
So last wednesday my left little toe was removed (doc has been wanting to do that for 3 years now, but i resisted until now) and that has slowed me down for a couple of weeks

But prior to the vacation was able to work on my sliding, to make it a better looking side, so added some 2x4s rigid insulation and an OSB board
Will get that finished as my foot heals more



20210822_192945.jpg

even earlier I had installed some pvc moulding around some of the windows

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so in time My-Old-House will look better than peeling old paint lol

still off grid since April 28th
looking to finish modifying the last 2 355w panels with MC4 connectors and getting them hoisted,.........somewhere

that will give me 8,000 watts of Voc
 
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also a friend is also building a tesla based battery for his house build - power first though. He stacked his 4 modules directly on top of each other and used the C bars from Jack Rickard's store to connect

gave me an idea to pack better density in my pack

current 8 modules pack below:

2021-05-12 Modules 7&8.jpg

I measured the space and I can put a third layer of modules in that space with room to spare. When I built the shelves I put 13 inches between them, then seeing the above I thought I messed up. Rather, by accident I see the better result of 3 horizontal modules per shelf

NICE

am pondering the weight support of the 3/4" plywood - it is supporting 220 lbs now, will it support 330 lbs? maybe put a cross member or two under it for added support.

anyway, feeling good about - day dreaming about 120 kwh of battery is possible
 
Had my first grid reconnect event of the season since April 28th and a small thing went wrong

BEFORE the inverter could switch to grid (Set for 38.4v), the Jack-In-The-Box (JITB) battery controller disconnected (at 38.7v) and shut the inverter down entirely around 3AM. I woke up around 4AM and sensed something was wrong as the nightlights were out

the issue was that the variance between cells is set to 0.200v, if the difference between the high and low cells is that or greater, the JITB disconnects to ensures no single cell goes below 3.00v, which would damage the cell. I think the most recent modules I acquired and added have some weaknesses at low voltage.

CELL View.jpgfull view.png

I had to set the variance to 0.300v in order to stabilize it long enough to do more diagnosis.

As can be seen, it is not properly bottom balanced. As the grid powered the house from 4AM to around 10AM, the system did some balancing.
I will be setting the inverter's Low Battery Transfer to grid voltage to 39.0v, up from 38.4 to stay above that problem area.

36.0v is totally dead, the JITB has a pack voltage of 37.0v as a final disconnect safety limit, along with the variance disconnect trigger.
If the modules were more equal, then I could utilize a lower Low Battery Transfer voltage of 38 or the 38.4 I had it at.
So consider a mix of usedbatteries, I guess I will bump to the 39.0v


As my goal is to add more modules to be able to have a larger battery reserve I aim to keep the battery voltage at 45v or higher most of the time.
This set of 40wkh lasted a little over 2 days of heavy cloud cover and rain, as it steadily declined from 48v to 38.8v over that time

I roughly deduce 20kwh provides me a single day of storage. My goal of 5 days seems to be satisfied with a bank of 100kwh. I can support 110kwh in space and interconnects
 
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Had my first grid reconnect event of the season since April 28th and a small thing went wrong

BEFORE the inverter could switch to grid (Set for 38.4v), the Jack-In-The-Box (JITB) battery controller disconnected (at 38.7v) and shut the inverter down entirely around 3AM. I woke up around 4AM and sensed something was wrong as the nightlights were out

the issue was that the variance between cells is set to 0.200v, if the difference between the high and low cells is that or greater, the JITB disconnects to ensures no single cell goes below 3.00v, which would damage the cell. I think the most recent modules I acquired and added have some weaknesses at low voltage.

View attachment 68189View attachment 68190

I had to set the variance to 0.300v in order to stabilize it long enough to do more diagnosis.

As can be seen, it is not properly bottom balanced. As the grid powered the house from 4AM to around 10AM, the system did some balancing.
I will be setting the inverter's Low Battery Transfer to grid voltage to 39.0v, up from 38.4 to stay above that problem area.

36.0v is totally dead, the JITB has a pack voltage of 37.0v as a final disconnect safety limit, along with the variance disconnect trigger.
If the modules were more equal, then I could utilize a lower Low Battery Transfer voltage of 38 or the 38.4 I had it at.
So consider a mix of usedbatteries, I guess I will bump to the 39.0v


As my goal is to add more modules to be able to have a larger battery reserve I aim to keep the battery voltage at 45v or higher most of the time.
This set of 40wkh lasted a little over 2 days of heavy cloud cover and rain, as it steadily declined from 48v to 38.8v over that time

I roughly deduce 20kwh provides me a single day of storage. My goal of 5 days seems to be satisfied with a bank of 100kwh. I can support 110kwh in space and interconnects
Interesting.... thank you for being our guinea pig :)
 
You're totally working all the bugs out of this system for us all.... very helpful..

Jen
at least providing some possible gotcha's.

I had had concerns back in the day of what happens to the pack when adding modules over time.
I can see that my Low Voltage Transfer needs to come up, as pointed out, to keep away from issues near the bottom
 
First picture is production from Friday Oct 15 where the battery starts off TOTALLY EMPTY and charges to 100% FULL.
We have had several cloudy days where the battery declined day after day

Near perfect production bell curve, green line is CURRENT

Grid connected at 11PM evening before when battery voltage hit 38.6 volts (this is up from my prior floor of 38.4v, as well has my variance value is now 0.300v, as recommended by the manual for the Jack-In-The-Box. I had used 0.200v when I had the prior power shutdown event)

House ran on grid while solar charged the batteries
Then at 10AM grid disconnected at 42volts totally, and solar only proceeded to full charge the battery and run the house

total production for the day was 40.1 kwh - a good day for 7300(Voc) watts of panels


near perfect geneation day.png



not so much about solar, but my new siding project is progressing finally.

Last week I was released from having to use crutches so I can walk freely now that the foot is healing from surgery

so yesterday put the final 2 OSB panels on the south side upgrade - this is near where I had put up the scaffolding for the panels on the roof.
Finally good sun, and walking ability.
Next will be tar paper and actual siding.

20211017_111437.jpg20211017_111442.jpg
 
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Refactored the battery case to get ready for more modules and positioned the Jack-In-The-Box (JITB) on a top shelf to make room, and moved the Pi system status display. Changed powering the pi from AC to a 12v DC.
Added serial communications channel between the JITB and the Pi display.
Wired hardwire ethernet to the Pi display instead of using hard to reach Wifi

BEFORE picture of battery shelf


2021-05-12-modules-7-8-jpg.62386


AFTER picture

JITB and display just above eye level on their own shelves

20211018_134314.jpg

Extended NEG leg of JITB for now. after more modules are added I will remove the extension
will get better cable mount/clamps and fix the loose cables

20211018_134328.jpg

Two spare shelves now
currently one for tools and parts
second has more recent modules, awaiting $$ to order second module

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20211018_134257.jpg

Extended POS cable to reach bottom shelf, 4/0

20211018_134301.jpg


this gives me 2 full shelves to insert at least 8 more modules, 4 per shelf, providing 80kwh of storage

Possibility of doing 6 modules per shelf, and reaching 100kwh or even 110kwh
future options

and @Jennifer, I finally positioned the NEG tap high and POS tap low to spread the electron flow

I was asked for a wider view

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20211019_133601.jpg
 
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Module 10 arrived today. Some good wrapping that took me some time to unwrap. It is now sitting next to module 9 receiving a charge to make them equal. Here its taking almost 10 amps.

20211025_150638.jpg
 
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BEAUTIFUL... I need to get off my ass and get mine in, I've been busy putting up panels and took the summer off due to arm surgery...
 
BEAUTIFUL... I need to get off my ass and get mine in, I've been busy putting up panels and took the summer off due to arm surgery...
git'er going

Yeah, I was on crutches for 2+ months as my left little toe had to go. Took 2 surgeries to get the tissue to heal right, so I am right there with you girl!

Walking right at this point, so I ordered #10
Friday, 3 days ago, battery filled to top. Been decline ever since until this morning and grid connected. Today was mostly on grid, and with little sun yet batteries reached 42v and kicked off the grid. At this moment it is about to grid connect again - battery is low. For next 2 days, will be very little production as the California storm is hitting us tonight

NEED MORE BATTERY STORAGE

BTW, my friend got his 4kw of panels mounted on temporary mounts and is generating power under the clouds up here
He has 4 tesla modules and loves the extra power they have now. They are off grid at 7200 ft getting ready for the winter
 
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Equalized the old pack and the new modules to 47.0v and installed the new ones this morning

50kwh capacity now, with room for 60kwh more (2 shelves of 3 rows each) in the picture below.
In the lower left is a pane of plexiglass that I am installing across the front to keep hands out
Got this one to ensure a good fit

A second pane will be ordered shortly

20211026_124215.jpg
 
Between April 28th and Oct 9th, my system did NOT do an auto connect to the grid due to low battery SoC.
This is because of the following factors:

Number of good solar hours.
40kwh battery pack
No furnace on during the summer - but there were fans for cooling
No many cloudy days with rain nor snow

But on Oct 9th, the grid "backup" kicked in and ran the house until the sun could re-charge the batteries, usually the next day.

Since then until today, Oct 25th, there have have been 9 grid connection days.
Current flow from the solar panels, starts flowing shortly after 8AM and stops after 6PM now.

With the addition of the new 10kwh of batteries (to a total of 50kwh as mentioned above) I am observing how the grid connections will occur going forward. I hope they go down.

I hope to get to the point (60? 70? or more kwhs? we shall see) where the grid is not used any more
A very interesting experiment

dougbertInExile
 
Instead of 20 or 30 kWh more battery, how much more PV would be needed to accomplish the same goal?
Just overpaneling - you have enough SCC already.
(What we really need is a way to turn surplus electricity into fuel we can store in a tank.)
 
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