question

zeroco2 avatar image
zeroco2 asked

How far to oversize the PV part versus the MPPTs ?

Hi there. I would like to install two MPPTs 250/60, each with a string of 5 bifacial modules of 660 W (3300 W of installed power), one of the string oriented to the 120° (S-SE) and the other 300° (W-NW), non optimal orientations with 25° of roof slopes. The datasheet of the Smart solar 250/60 states that the "Nominal PV power, 48 V 1a,b)" is 3440 W. Till there, I feel nice.

If I paint my roof with a cool roof coating (a highly reflective paint), the PV efficiency of the bifacial modules can gain up to 25% according to the datasheet of the modules, meaning up to 4125 W of installed power per string (versus 3440 W of nominal PV power, or 48x60 = 2880 W of MPPTs output power): will my MPPTs eventually smoke in summer ?

MPPT Controllers
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Alexandra avatar image
Alexandra answered ·

@ZeroCO2

As long as you have not exceeded

1. the input voltage at min temps

2. The short circuit ability of the MPPT (60A input)

You will be fine. You will get power limiting but thats ok as well. PS they will get hot so make sure they have plenty of space.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.