I am planning an installation in a shipping container used as a small office. The unit is going to be completely off-grid, with a 2kw generator as a backup.
What I need the system to do:
Power an 8000 BTU A/C during the day in the sun (1000W roughly)
Power a small microwave occasionally (We can turn off A/C to run microwave if needed)
Power 3-4 IP cameras, NVR, POE Switch for 2 outdoor wireless point-to-point devices
Power a 32" LED TV for camera monitoring during the day
Provide power for charging of phones and tablets
Equipment I'm thinking of using:
4 3.5KWh 24V LifePo4 battery packs in series-parallel for 14KWh at 48V
3kw/9KW 48V hybrid inverter/MPPT charger
12 245W solar panels in 4 parallel banks of 3 panels in series
Obviously I'll need some BMS setup. I'm thinking of using 2 seperate 16-cell BMS's set up so that either pair of 24v batteries can shut down if there is a cell problem leaving the other pair connected. Any recommendation on a BMS setup that would handle this?
I'll also need a way to connect the panels to the system. Amazon sells some interesting solar combiner boxes with distribution and circuit breakers installed. Has anyone had any experience with these? I figure each bank of panels will produce an open voltage of 112.5V and figuring 245W panels, that should put the load on each bank at 6.5A with a total theoretical load through the PV cables being about 26A. I know my numbers are all assuming 100% efficiency which won't happen, but it makes the math easier. The cable run between panels and inverter won't be longer than 15 feet. With all of this being the case, I'm thinking wire gauge should be 10AWG between panels and 6AWG or 8AWG between the combiner and inverter.
Any feedback anyone here might be able to provide would be greatly appreciated. Let me know if I've made any mistakes in my planning so far. If there are better options for any of this I'm open to that as well. Nothing has been purchased yet, so nothing is set in stone.
Thanks everyone.
