Solar cabling... can i just double double check my thinking?

[robtheplod]

Hi All

 

I'm now putting together my shopping list for the structure so i can wire up a MPPT controller - connections to battery etc and i just wanted to check something. I'm as yet undecided on panels (will be max of 1000w in total) or the actual MPPT controller but it will be a Victron 100/50 or 150/70, so max 70 amp @ 12v. The 100/50 can physically take 16mm cable and the 150/70 can physically take 35mm. As the very max output will be 70amps I'm thinking 16mm cable should be fine at a rating of 110amp (all fused appropriately) for either controller. Have i missed anything with the cable sizing - i keep thinking the two models have different sized cable connections for a reason???

 

thanks!!!

rob

[Tony Brooks]

9 minutes ago, robtheplod said:

Hi All

 

I'm now putting together my shopping list for the structure so i can wire up a MPPT controller - connections to battery etc and i just wanted to check something. I'm as yet undecided on panels (will be max of 1000w in total) or the actual MPPT controller but it will be a Victron 100/50 or 150/70, so max 70 amp @ 12v. The 100/50 can physically take 16mm cable and the 150/70 can physically take 35mm. As the very max output will be 70amps I'm thinking 16mm cable should be fine at a rating of 110amp (all fused appropriately) for either controller. Have i missed anything with the cable sizing - i keep thinking the two models have different sized cable connections for a reason???

 

thanks!!!

rob

 

Yes - cable run length. Always ignore the stated currant capacities for runs 9out and back) of more that (say) four meters. Do the volt drop calculation to find the cable size needed for your runs of cable.

[magnetman]

I've got 4 victron MPPT controllers (20/100, 30/100 and 50/150). I dislike the choc block screw terminal connectors on these. They could have done better specially with the spacing between wire inputs. 

 

As for the output wires to the battery if you find the wires are getting hot you can reduce the max amps via the app as long as you get a "Smartsolar" rather than a "Bluesolar". 

 

For some unknown reason the "Bluesolar" is the one which does not have Bluetooth connectivity. 

 

 

Edited January 9, 2023 by magnetman
Edit to correct weight units

[robtheplod]

There's probably 2 metres between the battery and MPPT location so hopefully this might not be too much of an issue?

[BEngo]

12 V Planet's voltage drop calculator says both are OK for a 4m round trip. (max current, max cable size)  Even 70 A through a 16 mm2 cable produces an acceptable voltage drop at that length. 

 

N

[Sea Dog]

On 09/01/2023 at 16:22, magnetman said:

For some unknown reason the "Bluesolar" is the one which does not have Bluetooth connectivity. 

A glimpse into the unknown...

 

The casing of practically everything Victron make is coloured blue. They have long referenced this in the name of some items (e.g. bluepower, bluesolar). When they added Bluetooth to some of this blue coloured kit, so it could send data to their App and hence make it "smart", they used they word 'smart' to make it easy to identify which bits of kit have this facility.