Expanding Solar System - MPPT and Array Connection

Hi everyone,

I’m looking to expand my solar system and need some advice. Here’s my current setup:

  • Inverters: MultiPlus-II 24/3000/70-32
  • Monitoring: Cerbo GX
  • Charge Controller: SmartSolar Charger MPPT 250/60 rev2
  • Batteries: Pylontech UP2500 (3 units)
  • Panels: 4 SUNPOWER SPR-P6-405-BLK

My current panels only produce power until around 2 PM, with a maximum of 1100W. I’m considering adding 4 more panels on the opposite side of my house to capture more sunlight.

My questions are:

  1. MPPT Compatibility: How will my MPPT handle the additional panels? Will it be able to efficiently manage the increased power output?
  2. Parallel Connection: Is it feasible to connect the two arrays in parallel? What are the potential benefits and drawbacks of this approach?
  3. Additional MPPT: Would it be better to invest in another MPPT to handle the additional panels separately?

I’d appreciate any insights or recommendations from the community.

Thanks

Additional mppt,

If you connect the extra panels to the ones already installed, the “shaded” panels will power down the “unshaded” ones

Extra panels i would suggest to be in better location- south facing optimal.
Why do existing only produce to 2pm? May be worth moving them to better location.
Try out one of the solar calculators to see what available locations for panels would produce in power gains.

Hi @yurakril
Into those batteries your /60 mppt is good for ~1700W. Depending on the panel orientations, you may/may-not see some flatlining in output at peak times. If you think that’s sufficient, then you could run with just the existing mppt.
Presumably your 4x existing panes are series wired, so to add another string you need to match the string Vmp. Either with identical panels or similar Vmp spec. Usually Vmp is fairly constant even with varying sun, so the different orientations shouldn’t normally matter.
You could confirm this by isolating one string at a time (wait 10 min for a retrack). Easy if you run separate wire pairs from each side of the house.
The worth of adding another mppt is for you to decide. But you can do it later.

Hi,

1700W is a perfectly sufficient number for me. My current goal is to have all-day generation.
I plan to buy the same solar panels and use another pair of cables to connect them to the MPPT.
As I understand it, if I connect 2 arrays of 4 panels to one MPPT, I can get a maximum of 130V and 30A from both.
According to the technical specifications of my MPPT, these are the allowed limits even at the maximum generation of both arrays, the only downside is the 1700W limit but as I said before, it is acceptable for me.
Please correct me if I’m wrong.

Thanks to everyone for your help.