Solar Panel feedback

[DavidS]

Hi,

I am interested in using these panels on my RV solar build:

https://www.greatsolarpanels.com/wp-content/uploads/2019/08/Datasheet-SPR-230-WHT-U.pdf

The mechanical characteristics are advantageous for my build, but I am curious about how they would behave in an SBMS0 system with DSSR20's as they are 72 cell panels with, it seems, somewhat odd electrical characteristics.  I know they'll work, perhaps with some inefficiency but, thoughts?  

DC Electrical Characteristics

• STC Power Rating 230W 
• PTC Power Rating 212.3W 1
• STC Power per unit of area 17.2W/ft2 (184.8W/m2) 
• Peak Efficiency 18.5% 
• Power Tolerances -5%/+5% 
• Number of Cells 72 
• Nominal Voltage not applicable 
• Imp 5.61A 
• Vmp 41V 
• Isc 5.99A 
• Voc 48.7V 
• NOCT 45°C 
• Temp. Coefficient of Power -0.38%/K 
• Temp. Coefficient of Voltage -0.133V/K 
• Series Fuse Rating 20A 
• Maximum System Voltage 600V

[Nils]

David,

assuming that you are running a 8S / 24 V system, the added 12 cells (compared to 60 cell panels) will not add any benefit. Except that you could allow higher voltage drop on your solar cables.

The panel will act as a current source. As soon as DSSR20 connects the panel to the battery, the voltage will be limited to battery voltage (actually slightly above). The panel then will deliver the rated current (around 5 to 7 amps depending on conditions, I would guess). If every watt counts, you would have to work with an MPPT charge controller, I guess. Usually it's not worth the effort and extra money.

I personally would research if you can find any 60 cell / 120 half cell panels with same mechanical specs. That would match the system pretty nicely (assuming 8S).

Best,

Nils

[Dacian Todea]

David,

As Nils already mentioned assumption is that you will have an 8s system so 24V.

You can likely find similar size panels that are 60 cells and those will perform much better as the extra 12 cells are just that extra and will not help with anything.

 Such a panel will push probably around 6A in to battery and size is about 80cm x 155cm while a 60 cell panel with 6" cells is not that much larger around 100cm x 165cm and will push about 11A in to battery.  Is almost that you will need two of this 72 cell panels to do the same as a single slightly larger 60 cell panel.

[DavidS]

Dacian, Nils' response was very helpful to drive my understanding.  Ideally, I'd love to find some 31.5" wide 60 cell panels, unfortunately, it seems to be very difficult to search for solar panels by specs.  So, I'll keep digging.  There are lots of 60 cell 39.5" wide panels in the market.  Might have to figure out how to use those instead :). 

As always, thank you for your efforts, product and time.