Solar panel connection setup.

[Mattcia123]

Hi all,
I installed one solar panel a little while ago and would like to add another. My question is how do I connect the solar panels together? Do I need those Mc4 coupling adapters? Or can I just wire them together somehow? Right now my solar panel is just wired to the controller and then to the battery. Thank you and sorry for the amateur question.

Matt

 

[Will Gilmore]

Can you describe your panels and controller? What wattages are you dealing with, etc. What kind of controller?

I also don't know much about this subject, so I'm following along.

Sunny sailing.
-Will (Dragonfly)

 

[Sailm8]

This is what you need but you also need to correctly size your controller. https://www.amazon.com/BougeRV-Conn...id=1582456053&sprefix=solar+connector,aps,171

 

[JK_Boston_Catalina310]

The MC4 connectors are really the best option because they are waterproof and give flexibility for series and parallel connections.

As far as what is going to work on your boat: are the panels identical? what are the panel specs? what are the controller specs? what is the physical layout of the panels?

For your current setup, I would personally add a breaker between the panel and the controller. You should also have a breaker or fuse between the controller and the batteries.

 

[AaronD]

For your current setup, I would personally add a breaker between the panel and the controller. You should also have a breaker or fuse between the controller and the batteries.

Definitely a breaker or fuse between the controller and batteries (on the battery end). That's mandatory to protect the wires from burning up in the case of a short circuit (Note that breakers and fuses are specifically to protect the wires).

Solar panels are current limited. I.e., even in full sun, a solar panel can't put out enough current to fry the wiring between the panel and the controller (presuming you didn't do that run in stupidly small wire, like 24 AWG). At least that's my reading of @Maine Sail's advice in Thoughts on my Solar Plan and Fusing question.

So I might be corrected by someone more knowledgeable, but I think a breaker between panel(s) and controller is optional - only if you want the ability to switch off the panels without unplugging them (and for that, a simple switch would work fine too, you don't need a breaker). The only way to see dangerous current levels in the solar panel wiring would be a short in the controller (letting battery current flow through the controller to the panel wiring). And since the panels only connection to the battery is via the controller, which we've already protected with a fuse/breaker on the battery end, we're safe there.

And to reiterate: Definitely include a breaker or fuse between the battery and the controller, within 7" of the battery.

 

[jssailem]

I think a breaker between panel(s) and controller is optional - only if you want the ability to switch off the panels without unplugging them

Or, you could put a cover on the panel and effect the same result.

 

[JK_Boston_Catalina310]

Definitely a breaker or fuse between the controller and batteries (on the battery end). That's mandatory to protect the wires from burning up in the case of a short circuit (Note that breakers and fuses are specifically to protect the wires).

Solar panels are current limited. I.e., even in full sun, a solar panel can't put out enough current to fry the wiring between the panel and the controller (presuming you didn't do that run in stupidly small wire, like 24 AWG). At least that's my reading of @Maine Sail's advice in Thoughts on my Solar Plan and Fusing question.

So I might be corrected by someone more knowledgeable, but I think a breaker between panel(s) and controller is optional - only if you want the ability to switch off the panels without unplugging them (and for that, a simple switch would work fine too, you don't need a breaker). The only way to see dangerous current levels in the solar panel wiring would be a short in the controller (letting battery current flow through the controller to the panel wiring). And since the panels only connection to the battery is via the controller, which we've already protected with a fuse/breaker on the battery end, we're safe there.

And to reiterate: Definitely include a breaker or fuse between the battery and the controller, within 7" of the battery.

The reason for the breaker is to depower correctly without damaging the controller.