Blocking Diodes on solar panels

[Dunx]

I am looking to instal 2 solar panels on our boat. One is 120W the other 80W. The sizing and semi flexibility is due to fitting them on the garage and pilot house roof. I intend to use a Victron 75/15 charge controller.

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

The panels operate at the same voltage and I understand that due to their differing output they should be installed in parallel for best efficiency. Due to location some shading is also inevitable. Each panels will likely have their MC4 connectors removed and the cables brought through glands to a fuse (10amp?) for each panel and then on to an adaptable box for connection before the charge controller. Should any further switch option be installed ?

I have read loads of posts on here but remain confused as to whether it is necessary to instal a blocking diode on each panel. If so is it best to re-terminate the cables with MC4‘s and use MC4 propriety diode connectors or to use a “Schottky diode” on a termination block inside the adaptable box? I know little about electronics so could anyone recommend suitable diodes if they are needed?

 

[emmalina]

they will already be installed on the panels normally/ Or your controler will sort it out

 

[noelex]

Blocking diodes are not necessary or benificial for your proposed installation.

A switch between the controller and the solar panels is nice, but it not essential.

When disconnecting the controller from the batteries, the connection between the controller and the solar panels should be disconnected first. So if you are planning to regularly disconnect the controller (for example by turning off the main battery switch when leaving the boat), then I would install a switch between the controller and solar panels to make this sequence easier. However, if you intend to keep the solar controller normally permanently connected to the batteries, then for the occasional service you can simply disconnect the wires leading from the solar panel to the controller (or cover the panels with a towel) and save the complication of a switch.

 

[Graham376]

they will already be installed on the panels normally/ Or your controler will sort it out

Don't count on the controller sorting it out, some don't as I found out with a previous one. I've kept the MC4 connectors and used diodes.

 

[noelex]

Nearly all (but there are exceptions) modern solar controllers will disconnect the panels at night.

The Victron 75/15 will do this and is better without blocking diodes.

 

[AntarcticPilot]

Don't count on the controller sorting it out, some don't as I found out with a previous one. I've kept the MC4 connectors and used diodes.

I only have a single panel, but I found a blocking diode necessary with the Photonics Universe controller.

 

[emmalina]

OK I will rephrase that to "Any decent controller"as I have a box full of chepo controllers I have changed over the years !