Largest single 12v panel and maximum voltage

[kitling89]

When I upgraded my boat's electrical system I installed a Renogy DCC50S 12V 50A DC-DC Charger that regrettably has a maximum solar input voltage of 25V.

I understand this to mean the open circuit voltage (Voc) of the panel must be less than 25V? Or just the optimum voltage (Vmp) must be under 25V?

Either way, due to mounting constraints I would like to only install two panels but still get close to the maximum 660W this MPPT can handle. So far the largest single panel with voltage under 25V I can find is a Perlight Black 200w.

Any recommendations for larger panels with a max voltage of 25V?
Bonus points for being ready for a marine environment.

 

[snoobler]

Voc <=25V

Most larger panels have more cells in series than that, so I'll be surprised if you can find them. 200W is the biggest I've heard.

Why does it matter, 2 vs. 3?

 

[kitling89]

Thanks for the info.

Quantity 2 vs 3 (or more) is simply down to mounting configuration.

I decided to go with Victron 175w x2 for now as I found a good deal on them in the UK.

 

[snoobler]

I asked because it doesn't matter how many panels - it matters how much surface area they have. If you have 200W of panels, and you want 600W of power, you need to use 3X the area. If you're limited by physical size, then that's the limit on your power as well.

In other words, that 660W is going to take about the same surface area whether it's 2X 330W panels (HUGE) or 3X 220W panels. Actually, the 220W panels will take a little more space because you have a few inches more in panel frames.

 

[kitling89]

Sure. I have virtually unlimited area as it is off the back of a boat. On the other hand it would be easier to utilize the mounting location for 2 large panels rather than having to construct additional subframe for many smaller panels.
Hopefully you understand it is down to convenience of mounting rather than an attempt to reduce total surface area.

That being said I can guess in the real world where additional area is added by the panel's borders, there is some small advantage to reducing total area by going with fewer, larger panels.