Resistance is futile

[Mrjmegson]

Hey guys, most of you are going to think this is a little OTT, but please indulge me.

I obviously want to get the most out of my solar system, especially with the naff weather we have over her (UK), so I want every bit of my system to be as efficient as it can be.

So, wire resistance. Binky said that the wires on the back of the panels (not looked) will be 4mm², and all the wire I'm bringing down through the house will be 6mm². Now the resistance of 4mm² is more than double that of 6mm², so I obviously want all 6mm² in the system.

In light of this, I'm thinking of chopping the wires off the panels as close to the panel as I can get and replacing it with 6mm².

Am I to assume that this will reduce the resistance, as the length of a wire will also increase the resistance, so the shorter the 4mm² the better? Or will the 4mm² set the resistance for the whole line, like having a resister in the line?

Sorry, I've tried to read up on this, but can't find an answer to this.

Be kind with your replies.

Jay

 

[SPECIAL LOCATION]

Do you have any physics or electrical science knowledge?

As from your post it sounds as though you probably need to be googling information about the electrical theory aspects of physics, to gain some understanding of resistance in electrical circuits.

Why do you consider that a 4.0mm CSA will be more than double a 6.0mm CSA conductor? (I am assuming the same material of construction?)

 

[Mrjmegson]

I have very basic Physics and electrical science knowledge, which from you're question, I think you can tell.

I could spend hours reading up on things that I probably won't understand, or I could use that time more productively and ask someone more knowledgeable than myself for a simplified answer that I will understand.

I don't even understand your question in your last paragraph, I don't know if you're asking me why the resistance is double, or why "I think" it is double.

 

[binky]

Hey guys, most of you are going to think this is a little OTT, but please indulge me.

I obviously want to get the most out of my solar system, especially with the naff weather we have over her (UK), so I want every bit of my system to be as efficient as it can be.

So, wire resistance. Binky said that the wires on the back of the panels (not looked) will be 4mm², and all the wire I'm bringing down through the house will be 6mm². Now the resistance of 4mm² is more than double that of 6mm², so I obviously want all 6mm² in the system.

In light of this, I'm thinking of chopping the wires off the panels as close to the panel as I can get and replacing it with 6mm².

Am I to assume that this will reduce the resistance, as the length of a wire will also increase the resistance, so the shorter the 4mm² the better? Or will the 4mm² set the resistance for the whole line, like having a resister in the line?

Sorry, I've tried to read up on this, but can't find an answer to this.

Be kind with your replies.

Jay

And how are you going to join the cables in a reliable for 30 years sort of way?

Apart from invalidating any warranty, this really is a bad idea, try calculating energy lost rather than just looking at cable resistance. Last time I did that on an AC cable run of over 120m losses were in the order of 60watts, or ****** all in layman's language

 

[johnb2713]

I have very basic Physics and electrical science knowledge, which from you're question, I think you can tell.

I could spend hours reading up on things that I probably won't understand, or I could use that time more productively and ask someone more knowledgeable than myself for a simplified answer that I will understand.

I don't even understand your question in your last paragraph, I don't know if you're asking me why the resistance is double, or why "I think" it is double.

Example
6 kW array running around 300v. The difference between the losses in 4mm2 and 6mm2 is 64w IF the cable run was 100 metres.

 

[Mrjmegson]

Oh wow, that's really not worth it at all then for my 20m cable run.

Lovely, thanks for the clear answers guys, I obviously won't bother now.