Number of panels

[Jason Dunkin]

I have a 7ft by 14ft area on my shed. I can go with a 100W panel and fit about 8 panels, 8 x 24.3Voc = 194.4V. Or I can go with 550W panel and fit about 4 panels, 4 x 49.95Voc = 199.8V. Is it better to go with small watt panel but increase the number of panels or go with a bigger watt panel and decrease the number of panels ?

 

[robby]

Your basically asking is 800W better than 2200W of panels in the same space.
Of course the 2200W is better, almost three times better.

 

[Jason Dunkin]

I was just looking at the Volts and not taking into consideration Amps (Isc). The 550W panel has much higher Isc (14.05 A) so makes sense to go with the 550W panels. This will be a series connection. Thanks for answering me.

 

[42OhmsPA]

Don't forget to account for cold temperature compensation.
What's your MPPT rated to handle?

 

[Jason Dunkin]

Thinking about getting the EG4 6K Off-Grid Split Phase Inverter or EG4 3K. The manual for the 6K units says 120 VDC~480 VDC and Max. DC Input current 27A. The panels will be in series.

 

[42OhmsPA]

You'll be fine, I'm running ~360voc ~15a on my TP6048 with no issues.
The 120v is minimum you need to get it to run, mine didn't like 3s during testing but 4s worked fine.

 

[Jason Dunkin]

Thanks.

 

[MichaelK]

A good rule of thumb I could mention here is that once the application needs more then approximately 300W, you always get better results, watt/$, ect. with bigger grid-tie panels. The only valid reason for going with 100W panels over ~300W total is either special spacing or weight issues.

 

[Jason Dunkin]

A good rule of thumb I could mention here is that once the application needs more then approximately 300W, you always get better results, watt/$, ect. with bigger grid-tie panels. The only valid reason for going with 100W panels over ~300W total is either special spacing or weight issues.

Makes sense, thanks.