My First Portable Solar Generator Build

[ender]

I've finally got everything and now I just need to put it all together. Before I do, I would greatly appreciate it if you guys could take a look at what I plan on doing and let me know if you see anything wrong with it.

List of equipment:

• MPP Solar PIP-2024LV-MK 2kW 24V All-in-One
• Two SOK 12V 100Ah batteries in series
• Three Solarever 365W (41.4 Voc per panel) in series
• 48V 100A surface mount breaker between batteries and MPP Solar box
• Anderson connectors between batteries and surface mount breaker
• 4 AWG copper cables between batteries and MPP Solar Box
• 8 AWG MC4 cables/connectors for PV
• 12 AWG extension cord for Grid input and MPP Solar box output
• Attached I've included datasheets for panels, SOK batteries, and MPP Solar box

Any and all feedback is welcome. Thank you.

 

[ender]

Alright well since I've gotten no response, I'll just use this thread to document my build. Maybe it will be useful for someone in the future.

First things first. I finished top balancing the two batteries and then I disconnected them from each other so I could do a capacity test on each one.

The following is the result. I used a 10A (0.1C) load (maximum power my electronic load could handle) and ran in it until it hit the 1280Wh rating of the battery.



As you can see, at the 12.2V mark there's only about 40Wh of capacity left due to the sharp drop off. I calculated the impedance of the battery + setup to be 0.04 ohms based on the fact that the batteries measured 13.3 Vocv (open circuit voltage) and then I placed a 10A load, they dropped to 12.9V.

(13.3V - 12.9V) = 0.4V drop
R = V / I = 0.4V / 10A = 0.04 ohms

This impedance is not static and will change with temperature and state of charge so now the question is: what should I be setting my MPP Solar low voltage cut off to based on this data?

• Should it be the 0.1C loaded voltage of 12.2V (24.4V for both batteries in series)?
• Should it be the Vocv equivalent voltage (12.6V or 25.2V for both in series)? I don't think this should be the case since there will be some current being drawn from the battery when the low voltage cut off trips.
• Should it be the whatever the equivalent voltage will be when the battery is sourcing as much current as the MPP Solar box allows (~100A)? This would not make sense since the low voltage cut off would have to be 16.6V:
  100A x 0.04 ohms = 4V
  12.6V + 4V = 16.6V

Next step is cutting wood and making cables to mount everything.