Solar set up

[Adam1991]

Hi, we’re researching setting up our solar panels - we will be installing 2 x 200w panels. 
 

At the moment we have a victron mppt 100 / 30 with 6mm cables fitted from mppt to panels side.
 

We’re wondering how to connect up to the batteries which are roughly 2metres away in the engine bay. 

What thickness cable mppt to batteries? 
 

Fuse in line between mppt and batteries? Also, how big of a fuse?
 

Any fuses elsewhere required? 
 

Thanks and apologies for so many questions. Total noobs to Solar. 
 

thanks, 

Adam 

 

[GUMPY]

3 hours ago, Adam Mc Gowan said:

What thickness cable mppt to batteries? 
 

Fuse in line between mppt and batteries? Also, how big of a fuse?
 

Cable thickness should be the largest that will fit in the controller probably 16mm

Fuse should be as close to the battery as practicable and of a rating to match the cable.  

[Tony1]

2 minutes ago, Loddon said:

Cable thickness should be the largest that will fit in the controller probably 16mm

Fuse should be as close to the battery as practicable and of a rating to match the cable.  

 

Apologies, not meaning to contradict, as I know you've forgotten more about electrics than I'll ever know, but I seem to remember reading advice somewhere that it was normal to use a fuse rated at about 50% more than the charger/MPPT? 

So that would mean a 45 or 50amp fuse in this case? 

 

 

[GUMPY]

22 minutes ago, Tony1 said:

 

Apologies, not meaning to contradict, as I know you've forgotten more about electrics than I'll ever know, but I seem to remember reading advice somewhere that it was normal to use a fuse rated at about 50% more than the charger/MPPT? 

So that would mean a 45 or 50amp fuse in this case? 

 

 

Fuses are there to protect the cable and for no other reason unless of course they are built into a unit in which case they are there to protect the unit. 

[blackrose]

I've got 6mm2 solar cable from the panels to the controller and 40mm2 cable from the controller to the batteries. I think the max specified battery cable for my Epever 60A controller was 35mm2 but I had 40mm2 available and managed to squeeze it into the controller terminals. 

Edited March 11, 2023 by blackrose

[Jen-in-Wellies]

3 hours ago, Loddon said:

Cable thickness should be the largest that will fit in the controller probably 16mm

It is indeed 16mm^2. As it is only 2m from controller to batteries, that size will be fine and make fitting a fuse easier too.

[LadyG]

I bought a kit from Bimble Solar they have several kits , that will help to match up items. I also spoke to them as I wanted to match kit to battery bank

[Adam1991]

Thanks folks for your advice. We’ll go for 16+ mm sq for the cable and rate fuse accordingly. 
 

Cheers!