Originally Posted by FatBoySTL
As I plan to start off small and grow my solar system, to what degree can I mismatch solar panels going forward? With a proper MPPT controller, can I run panels with different output voltages/ranges? Different amperages? Different chemistry (mono vs poly)?
Not sure about the specifics, of this question. Its a best practice to use matched panels, but I think you can use different panels in some circumstances. Intuitively it seems like you would want all the voltages to be the same if wiring in parallel and the current to be the same if wiring in series, but that's just a guess.
Here are some videos to get you started:
What's Worse? Mismatched Solar Panels with Different Amps in Series or Parallel?
How to wire mismatched solar cells
With an MPPT controller rated at "100 amps", is that the amperage of the input? Output? Both? If just input, it seems I could run more panels in series to boost volts while keeping amps low, but if it also applies to the charging side, that 100 amp controller would be limited to 1300-ish watts regardless of panel wiring configuration.
The 'nominal current' (amps mentioned in the title) refer to output current. So regardless of what you do on the Charge Controller Input/PV Array side, the max it will be able to output is 100A.
There will usually be a separate max input current rating, and more importantly max input voltage rating. Because panels are rarely operating at 100%, it often makes sense to oversize your PV array a little bit as long as you stay within the input specs.
Through the course of the day, panel output goes fluctuates, but is that mostly a change in volts or amps?
This is something I'm still trying to wrap my head around. What I've gathered so far:
- Cell/panel temperature will affect volts
- Solar Irradiance (i.e. light intensity) will affect amps
- Angle will affect amps
- Partial Shade will mostly effect amps