Photovoltaic PV connection ???

[Remundo]

panels and rails probably already touch and are at the same potential.

If you want to play it fine, make a connection to the earth with copper ... but copper is expensive ...

Against lightning, it is important to see if your curls have a minimal surface. For that we must bring together the + and - wires,

because the risk of lightning is more by induction.

if the lightning falls directly on the panels, it is not the link to the earth that will save much ...

on the other hand induction loops are dangerous for the panels.

[chris34]

OK !
Thank you Remundo, yes I had already treated enough aspect induction loop ...

thanks.

[chris34]

Hello !!
I come back after X years of good functioning of my install' ;-)
(Big thanks to Gaston and Remundo!!! :-))

Today I want to change my panels.
I would like to put Alma Solar 410 Wp (ISC = 13,8 A) and VOC = 37,5V)
I think to put X 8. (=> about 3,2 KWp)

Currently, I have 4 independent strings, due to my inhomogeneous hardware configuration (roofs, ground, etc.)
So I would like to use these 4 strings for the following config:
4 X 2 PV in series each connected to Victron 75V / 15A or 100V / 15A chargers.

My question: do you think this solution is correct .. and above all not dangerous ;-) ???
Many thanks in advance!!
Chris.

[Christophe]

Er, you're reviving a topic from 2015 here...

A small updated diagram to refresh our memory and show the existing and the project would not hurt...

[Remundo]

on the voltages, the wires can take X00 V without any problem.

On the intensities, let's say that 15A is not the sea to drink. In general, PV cables are 4 mm² and take 20A without heating at all.

As usual you will have to check that the currents and voltages of the different strings are compatible with the converters where they are connected.

In parallel, the currents add and the voltage is common
In series, the voltages add and the current is common.

[Christophe]

The max PV DC input voltages of the major brand inverters are generally 600V, I believe I have seen some at 1000V…

600 V is a good fifteen panel at 35-40 V DC each in series...

On my string series of 10 PV poly, I capped at 360V big max… for 3000 W max… that's not too many amps…

ps: it's 6 mm2 Remundo...

[phil59]

Distance also plays a role here.

Between 5 and 100m, the section will not support the same at all.

In my case, floor panels, I have 6mm2, but given the distance, in AC, I can't transport much more than 3000W, in 220V.

But I was switching from DC to 600V, I could put more.

[sicetaitsimple]

I come back after X years of good functioning of my install' ;-) (
Today I want to change my panels.
I would like to put Alma Solar 410 Wp (ISC = 13,8 A) and VOC = 37,5V)
I think to put X 8. (=> about 3,2 KWp)

Out of pure curiosity, why change after 8 years of good operation? I thought that a PV installation lasted well over 20 years, excluding inverters?
So, add some panels to increase the power, why not? But change?

[Christophe]

It is possible to increase the peak power for the same size with more efficient panels.

By putting the last mono at 24% yield instead of poly at 16%, you still gain 50% annual production! It's nothing.

Afterwards, the best thing is to add a thong, but you have to have the space and the right orientation...

[Forhorse]

Between 5 and 100m, the section will not support the same at all.

The section supports the same whatever the length of the cable...
It's just that the losses by Joule effect end up making that over too great a distance there is nothing left at the end.