Design Review Requested - RV/Tiny Home With Grid Backup

[Luthj]

Greetings,

Quick background, we live in a large 5th wheel, and are intending to be grid independent 95% of the time. To this end I installing as much PV as will fit on the roof, and a battery/inverter system. Attached is a rough schematic, and I will list the core components I am currently considering. I am soliciting feedback. This installation doesn't need to meet code requirements (we live in AZ), and I will not be selling power to the grid (nor do I want to deal with a interconnect agreement). That being said safety is important, hence my solicitation for feedback.

Proposed Core components
Sol-Ark 12k-2P-N Inverter/charger
450W PV panels (specs shown below) 10 each currently, plus another 5 later.
SOK 48V 100AH LFP batteries (or equivalent, 3 each, possibly a 4th if needed later)

I will do a couple follow up posts with specific items.

 

[Luthj]

For panel mounting I am considering running aluminum half height unistrut the length of the roof and then using clamps like the ones shown below. I will use spacer blocks under the unistrut (about 1/4") to allow drainage, and screw the strut to each of the joists. Two clamps on each edge long edge should get me enough strength. I don't have anything on my roof other than 3 low profile plumbing vents.

 

[Luthj]

A few misc items.

Disconnect - I don't think I need one on the grid/hookup side, as the pedestal will have a breaker. The inverter has an integral PV disconnect.

Transfer switch - I don't see much value in a double throw transfer switch to bypass the inverter completely, but I am open to suggestions. Both the inverter and main panel have breakers

Neutral to ground bond. It looks like the inverter doesn't make one by default, so the bond will be at the pedestal. When off grid I will need to set the inverter make the bond (or install a relay to do so). I need to review the inverter manual to see if this is an option in software.

Fusing. I will have a pretty short battery to inverter run (less than ft), but opted for a fuse, despite the breakers on the individual batteries. Since the PV fault current is less than the wire limit, I opted to not fuse, but suggestions are welcome.


In this setup to avoid accidental export when on the grid, I will need to set a grid shave minimum to something like 50-100watts. I would welcome input from those who use this inverter.


For those curious here is our average hourly kwh consumption for the summer.