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Wiring Panels in Series-Parallel | Is this diagram correct?

You can cut it as close as you like if the math uses an accurate or conservative assumption for temperature coefficient and record cold temperature. That would mean it should never exceed, even on a record cold day with full sun hitting panels squarely.

0.003 temperature coefficient - what is on the data sheet for your PV panel?
11.7 degrees - is 11.7 degrees C below zero (-11.7C) the record cold for your location?

If those to numbers are accurate or conservative, you're good.

Multiple strings in parallel is OK, whether 3 or 6. Each string gets a fuse no greater than what panel label/data sheet says.
Wire from each string of gauge with ampacity at least as high as fuse.
Wire carrying combined current ampacity at least Isc x 3 x 1.56 (or Isc x 6 x 1.56); "1.56" is the multiple for PV string wiring and fusing.

If some PV strings are oriented differently from others (good to spread power production over the day) they will serve to pull Voc down because not all have full sun. Don't count on that to get away with voltage that would have exceeded 250V rating, but it will pull 246.6V even lower.

6s3p would be preferred over 3s6p to reduce current and wire gauge.
But it is possible efficiency is reduced with the greater voltage reduction performed by MPPT circuit.

What is the MPPT voltage range of LV6548? I couldn't readily pull up a data sheet.
There is the chance that 3s for nominal 111Vmp would drop too low on a hot day, if minimum MPPT input voltage is close.
 
I'm also in Arizona (Phoenix Area). We are planning a remodel on what is essentially a tear-down home for my neighborhood. We have been in the home for 18 years, so we are not scared to upgrade a little.

I’m building a very similar system to what has been described in this thread (the only difference is the panels, I'm using the T Series 230W 60 cell poly with 37.0 VOC https://store.santansolar.com/product/santan-solar-t-series-235w/ ).

I’m trying to copy Will Prowse’s system “DIY 13kW 48V Offgrid Solar System: How to build it from scratch!” I don’t mind spending a little extra money on good components, due to the fact that my “solar lab” (and new mini-split) will be the only mechanical system that makes it to house 2.0.

I purchased 20 panels in December from SanTan
I ordered one (1) LV6548 from Ian (watts247) last week and I’m expecting it in March.
When I have the system setup (temporally, see below) I intend to order one (1) 48V 100AH EG4LL LCD Battery by EG4 to get me started.
If I can prove a use case to myself for solar in house 2.0 with a reasonable ROI, purchase an additional one (240V) or two (spare or additional parallel unit) LV6548s & upgrade the solar panels.

My ideas for system use are:
- Purchase and install a mini-split capable of cooling a 1,400 sf 2x4 home in AZ or supplement my packaged system
(I’m on borrowed time on my packaged HVAC system)
- Power the water heater
- Install one 30 or 50 amp outlet on the backer board for a power distribution box (aka spider box)
- Operate some non-essential computer equipment
- [FUTURE] Charge an electric vehicle
* Please consider offering suggestions about additional circuits that could be relocated to my system to accelerate the payback.

I’m now struggling with the components, and I hope that “AZ Off-Gridder” and the community can review my shopping list to prevent any costly mistakes. I’m sure it’s all wrong due to the fact this is my first solar rodeo. Please don’t hesitate to apply correction to my list of components. I won’t do any price shopping of the components until I have my system design finalized.

I’m not sure how I intend to rack my system. I don’t want to spend money to hang it on the roof (south-facing) considering I will be replacing the roof soon (remodel). I would really appreciate any ideas on inexpensive and safe racking. Our home is located on a 9,000 sf lot so I have plenty of dirt. I would prefer a temporary mount that wouldn’t risk damaging a neighbor’s home during the first monsoon.

I will also include a photo of a solar fence that I proposed to my local municipality. I tried to get the city to buy off on a vertical mounted 140’ solar fence facing south to the alley (I understand that it would only operate at 50% efficiency). I couldn’t get my city to support my project, nor did I have any success in finding an engineer that would take on this project. In my mind, this was an excellent upcycle idea for used panels.
 

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