PV : Power vs Efficiency & Performance

[Bob Smith]

Hello

I am struggling to figure out what I should prioritize.
Both mono crystalline , half-cell

Panel 1
400W, 22.2% Efficiency , linear degradation +90% after 30year


Panel 2
470W, 21.2% Efficiency, linear degradation 84.8% after 25year

What do you think would prevail the Power of the efficiency and performance?

 

[binky]

with solar, I've always said size matters. Assuming you can get the same number of panels on the roof, go for the higher wattage, you don't need the efficiency if you have a larger array.

 

[Bob Smith]

Hi Binky,

I have done some sketches!!!

I have tried different layouts. That is I have played with different panels sizes (from the same brand), therefore different power.

Using the panels originally quoted:
1st quote 24 x 400W = 9600W
2nd quote 20 X 470W = 9400W

With trying different sizes based on availability on ITS website for the JA Solar brand (which was used for the 2nd quote)
15 x 545W + 4 x 405W + 2 x 460W = 9885W

As the second quote is already more expensive than the 1st quote, if I propose to use a mix of panels it will be even more expensive. I am talking about between 2 to 3kGBP. I think I better stick with the 24 X 400W scenario.

The first quote use a 2 String MPPT inverter + Tigo Optimizer, while the second quote is with micro inverters. I believe micro inverters are significantly more expensive than the Tigo Optimizer but there is no need of an inverter.

The drawback you explained about having more connections point with micro inverters is surely the same with Tigo optimizer.