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BB submission flagged incomplete
I would like to present the following as an alternative submission (this setup includes an inverter and powers AC devices only at this time, and I built it 2 years ago so I don't have pictures of the unassembled parts):

I built this 24V system with the intention of using it off grid when I retire, and I purchased 4 used 6V batteries as I had several years to go and if I had to learn the hard way, better to use inexpensive batteries. The system consists of 4 300W PV panels, wired into 2 parallel strings of 2 panels in series (2x2). The panels can each produce a bit over 30V at a bit under 10A in standard conditions. Weather conditions and edge shading can cause higher voltage spikes. The typical input voltage sits around 70V and is managed by the charge controller. The charge controller can handle up to 140V before voltage protection kicks in, and can handle up to 60A input.

The panel input runs through a breaker, and then into the charge controller. The charge controller positive output runs into another breaker, then to a second breaker which connects to both the batteries (on the opposite side of the breaker) and the inverter (on the same side of the breaker). The negative feeds for the chrage controller, batteries, and inverter all attach to a negative bus bar, and the negative bar, charge controller, and inverter are wired to a ground bus which goes outside to a copper grounding bar in the soil. The panels are also attached to that grounding bar.

The batteries are wired in series with heavy gauge wire to minimize resistance. Each battery is rated at 220AH, so being in series this results in 220AH*24V=5.28kwh of total capacity. Since batteries can take permanent damage if their charge goes below 50%, the usable amount of power is limited to 2.64kwh in this setup. Typical daily use currently is around 800wh per day, powering my cable modem and wireless router if I leave them on over night. The inverter has a power switch, as does the power strip that these devices are plugged into so you can cut power to non-essential items when not in use, to minimize any phantom loads. When I first set everything up it was summertime and the panels would receive a good amount of sunlight (winter sun is blocked by trees in my tiny city lot) and I also powered my refrigerator using this system. That brought total power use closer to 2kwh per day and the used batteries were barely able to stay above 50% charge by early morning when they could recharge. I've avoided mounting the PV array to my patio roof at this time, but that would certainly improve performance as would adding 2 additional PV panels, one to each string for getting proper charging levels (10% of 220AH=22A input, while my system is closer to 19.3A max input) and higher overall power output.

While I don't normally charge my phone, I've included 2 pictures (one is a screen capture of the phone since I don't have another to take the picture) of the phone plugged into the inverter and showing it is receiving a charge. The highest power use I've attempted included the fridge, a power strip for my PC and other gear, and my window AC unit (rated at 960W) which was around 1500W when all were running at once. The inverter could handle that, although the cooling fans would turn on in that case. The highest PV input I saw was at that same time, the charge controller was reporting around 1100W+ out of a possible 1200 as conditions are rarely perfect. This was obviously not enough for everything, but I only ran the AC off solar once to see it work, and normally just the fridge, wi-fi, modem, PC, and light were powered that summer.
Power-Board.jpg
Power board-panel
Power board-panel
24V-Battery-Setup.jpg
6V batteries in series
6V batteries in series
PV-Panels.jpg
PV panels wired in 2x2 parallel-series
PV panels wired in 2x2 parallel-series
Phone-to-Inverter.jpg
Phone plugged into inverter
Phone plugged into inverter
Phone-charging.PNG
Phone charging
Phone charging
Staff note (gir bot) :

Someone flagged this submission as not complete.
BBV price: 1
Note: Sorry, need the before pictures and for it to be DC only. Maybe consider posting it in Electrical Oddball?

 
Posts: 82
Location: Currently south Wales (the old one!)
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Approved BB submission
So here it is.

Here is a 12v system for the shed. The battery is a 50AH, 12V, deep cycle, lead acid. Without any solar input it will just cover 100W for 6 hours, 50*12=600Wh. I used my phone to take the pictures, so I'm charging my ereader.

edit - The charge controller has a pair of built in usb ports (5V, 2A shared). There is a panel mount usb extension cord underneath the light switch, I installed this to protect the connector on the charge controller. The ereader is charging from that port.

The system is link to another shed with a 12v socket and USB socket (you can see the installed cable on the side of the shed). The lights won't be wired up until we fix the leak in the roof.
IMG_20210303_121430_3.jpg
Solar parts
Solar parts
IMG_20210212_102133_9.jpg
The shed
The shed
IMG_20210303_124006_9.jpg
50AH 12V Battery
50AH 12V Battery
IMG_20210317_105436_6.jpg
Charging my ereader
Charging my ereader
IMG_20210317_105551_9.jpg
The lights are on
The lights are on
IMG_20210317_105634_4.jpg
System installed
System installed
IMG_20210317_105614_0.jpg
Cover on
Cover on
IMG_20210317_115231_7.jpg
Finished shed
Finished shed
IMG_20210317_125915_9.jpg
USB
USB
IMG_20210317_150839_5.jpg
Drill battery charging on 12V
Drill battery charging on 12V
Staff note (gir bot) :

Mike Barkley flagged this submission as not complete.
BBV price: 1
Note: Needs a 5 volt outlet also.

Staff note (gir bot) :

Mike Barkley approved this submission.

 
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