How far can panels be from inverters in a 48v setup.

[Visionguild]

Hi there, I have 20 48v panels I'm wiring up in two groups of 5S2P to go to two inverters. So ten panels to each inverter. The panel set up is a little funky as the roof space I have is separated a tiny bit. I included a drawing of how they're going to be installed. Hopefully that helps. Do the main positive and negative parallel lead going from each group need to be the same length? Appreciate any help. Thanks so much.

 

[MisterSandals]

Are there any shading scenarios? Left to right, top to bottom?

Groups should be made with similarly shaded panels as much as possible.

Are the 6 panels on the right facing a different direction (slightly)?

 

[Visionguild]

Are there any shading scenarios? Left to right, top to bottom?

Groups should be made with similarly shaded panels as much as possible.

Are the 6 panels on the right facing a different direction (slightly)?

they are slightly. Not much I can do about it but it's not that much of a difference. otherwise they're all pretty much the same as far as shading goes. Nothing over them really. Open all around. Thank you.

 

[MichaelK]

What's the actual voltage specification on the back of the panels? Most likely it is NOT actually 48V? That being said, there's an easy voltage drop calculator you can use to determine your power loss at various distances.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

Just as an example, wiring 5 panels with an output of 48.0V each, you won't reach 2% voltage loss till you go out further then 250 feet when using standard 10 gauge solar cable.

 

[timselectric]

You can go as far as you want. As long as you run large enough wires.

 

[pvdude]

My PV panels Voc is 44vdc, so I wired 8S to get about 350vdc going to the charge controller/inverter.
Cable is about 250ft, so there is some small voltage drop.

 

[timselectric]

Sorry, didn't realize that you were not the OP.

 

[Visionguild]

So the panels are 315W and the open circuit voltage is 41.49 at 9.48 amps. I'm going for 207VDC at 19amps with the 5S2P setup. This is to fit with the controller. So can the + - wires be different lengths?

 

[Visionguild]

What's the actual voltage specification on the back of the panels? Most likely it is NOT actually 48V? That being said, there's an easy voltage drop calculator you can use to determine your power loss at various distances.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

Just as an example, wiring 5 panels with an output of 48.0V each, you won't reach 2% voltage loss till you go out further then 250 feet when using standard 10 gauge solar cable.
View attachment 94425

So the panels are 315W and the open circuit voltage is 41.49 at 9.48 amps. I'm going for 207VDC at 19amps with the 5S2P setup. This is to fit with the controller. So can the + - wires be different lengths? considering how I have to position the panels, one end is going to be farther away from the other.

 

[timselectric]

So the panels are 315W and the open circuit voltage is 41.49 at 9.48 amps. I'm going for 207VDC at 19amps with the 5S2P setup. This is to fit with the controller. So can the + - wires be different lengths?

6 gauge wire.
And yes, positive and negative can be different lengths.

 

[timselectric]

I'm counting 34 panels, in the picture.
That doesn't work out to strings of 5.

 

[Visionguild]

I'm counting 34 panels, in the picture.
That doesn't work out to strings of 5.

the bottom is an alternative way to group them, didn't know which would be best as I didn't know if the + - could be different lengths, see what I mean?

 

[timselectric]

the bottom is an alternative way to group them, didn't know which would be best as I didn't know if the + - could be different lengths, see what I mean?

Got it.

 

[Visionguild]

6 gauge wire.
And yes, positive and negative can be different lengths.

So someone else posted that if I just use 10g regular solar wire the loss would be minor, you think I need 6g? I'll have to order that I guess with the solar connectors already added.

 

[Visionguild]

What's the actual voltage specification on the back of the panels? Most likely it is NOT actually 48V? That being said, there's an easy voltage drop calculator you can use to determine your power loss at various distances.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

Just as an example, wiring 5 panels with an output of 48.0V each, you won't reach 2% voltage loss till you go out further then 250 feet when using standard 10 gauge solar cable.
View attachment 94425

This is wonderful. Thank you.

 

[timselectric]

So someone else posted that if I just use 10g regular solar wire the loss would be minor, you think I need 6g? I'll have to order that I guess with the solar connectors already added.

6 gauge gives a 2.13% voltage drop.
It's always recommended to keep the voltage drop below 3%.
10 gauge will have a 5.37% voltage drop.
All calculated at 250 ft.

 

[Visionguild]

6 gauge gives a 2.13% voltage drop.
It's always recommended to keep the voltage drop below 3%.
10 gauge will have a 5.37% voltage drop.
All calculated at 250 ft.

Oh, It's only a 30 foot at most distance. I used that calculator and got .65 with 10G. If I put in the right data

 

[timselectric]

Oh, It's only a 30 foot at most distance. I used that calculator and got .65 with 10G. If I put in the right data

Sorry, I think that I got 250 ft, from another post.
Yes, 10 gauge should be more than fine.

 

[timselectric]

You could actually use 14 gauge. At 1.63 % voltage drop. But, i would recommend at least 12 gauge.

 

[Visionguild]

Sorry, I think that I got 250 ft, from another post.
Yes, 10 gauge should be more than fine.

Wonderful. Thank you for your help. I appreciate it. I'm not sure if I'll need a combiner box or not. That's the next step after I get these panels up. I'm using 2 3000k LVM Growatts. Learning about all of this as I go. Thank god for this forum.