Where is the best place to parallel identical panels?
Warren-Pat_01 said
11:31 PM Jul 22, 2022
I've recently purchased another panel that is as close in specification as the original as possible. Connecting them in parallel, I'm thinking the best place to do this is just before the controller, using the same cable as before. A friend suggested using those "Y" connector cords but I see issues with them, particularly if the panels aren't side by side. I have a plug just before where it goes to the controller so that if required (camping in hot locations), I can plug a portable panels in.
What are the thoughts of the experts here? Will I need blocking diodes?
TimTim said
06:34 AM Jul 23, 2022
I use a Y connector with a short extension just to be able to provide separation between the panel. That way I only have one long extension cable to pack.
You do not need a blocking diode as your solar controller prevents any back flow of current flow from your battery back to the panels.
Whenarewethere said
08:14 AM Jul 23, 2022
Just knock up some short extension leads between panels & have one oversized cable from the "solar farm" back to the battery. I have modified my jumper leads to use them otherwise it is the best unused resource. Multipurpose your cables.
Mike Harding said
08:41 AM Jul 23, 2022
I have four panels and each has a cable of about 6m length, the four cables are connected together at the MPPT controller, no joiners or Y pieces just four cables stuffed into the MPPT connectors. Doing it this way give me maximum flexibility in placing the panels. As my panels are identical and each 38V, 5.3A I can get away with light cable.
Warren-Pat_01 said
10:08 AM Jul 23, 2022
Sorry everyone, I forgot to mention that this panel is going to join its mate on the roof of my poptop van.
Dick0 said
11:16 AM Jul 23, 2022
Warren-Pat_01 wrote:
Sorry everyone, I forgot to mention that this panel is going to join its mate on the roof of my poptop van.
Clear now.
Run cable from solar controller input to an Anderson plug. Then plug the portable panel to the Anderson plug when needed. This connection will keep panels in parallel.
Mike Harding said
12:52 PM Jul 23, 2022
It doesn't really matter where you connect them providing your're mindful of power loss, not much point in buying a new panel only to lose 25% of its output in the cables:
G'day Dick0,
What I have at the moment is the one rooftop panel connected to the controller via a DC "T" plug, socket enabling me to connect/disconnect the fixed panel or portable panels. The portables are 3x20w, the roof top is 55w. The new panel is again 55w.
Why didn't I add more to the roof? Weight for one (I'm getting weaker now. The original panel weighs 6kg, the new one 4) & two, our drain on the battery is minimal (a couple of LED lights, tv for a couple of hours & very occasionally, the pump. Since having the roof lifters regassed, the roof goes up easier.
It appears that putting both panels into a suitable weather proof junction box on the roof might be the best.
Thanks Mike for the calculator.
Jonathan, my few cables are multi-tasking, connecting almost anything to anything!The only thing they don't fit is the tv input (lol)
Aus-Kiwi said
06:56 PM Jul 27, 2022
I have two links on other side of regulator then one large wire ( 200mm long) to reg as all the wires wont fit in reg !
unusedname said
10:07 PM Nov 12, 2022
I have 3 similar panels and run individual cables until they get to the hot water service and then I join then in series, to give about 105 volts to the HWS. I also use it to power an electric drill, it will even boil the kettle if you are patient.
I've recently purchased another panel that is as close in specification as the original as possible. Connecting them in parallel, I'm thinking the best place to do this is just before the controller, using the same cable as before. A friend suggested using those "Y" connector cords but I see issues with them, particularly if the panels aren't side by side. I have a plug just before where it goes to the controller so that if required (camping in hot locations), I can plug a portable panels in.
What are the thoughts of the experts here? Will I need blocking diodes?
I use a Y connector with a short extension just to be able to provide separation between the panel. That way I only have one long extension cable to pack.
You do not need a blocking diode as your solar controller prevents any back flow of current flow from your battery back to the panels.
Just knock up some short extension leads between panels & have one oversized cable from the "solar farm" back to the battery. I have modified my jumper leads to use them otherwise it is the best unused resource. Multipurpose your cables.
I have four panels and each has a cable of about 6m length, the four cables are connected together at the MPPT controller, no joiners or Y pieces just four cables stuffed into the MPPT connectors. Doing it this way give me maximum flexibility in placing the panels. As my panels are identical and each 38V, 5.3A I can get away with light cable.
Clear now.
Run cable from solar controller input to an Anderson plug. Then plug the portable panel to the Anderson plug when needed. This connection will keep panels in parallel.
It doesn't really matter where you connect them providing your're mindful of power loss, not much point in buying a new panel only to lose 25% of its output in the cables:
Cable loss calculator
What I have at the moment is the one rooftop panel connected to the controller via a DC "T" plug, socket enabling me to connect/disconnect the fixed panel or portable panels. The portables are 3x20w, the roof top is 55w. The new panel is again 55w.
Why didn't I add more to the roof? Weight for one (I'm getting weaker now. The original panel weighs 6kg, the new one 4) & two, our drain on the battery is minimal (a couple of LED lights, tv for a couple of hours & very occasionally, the pump. Since having the roof lifters regassed, the roof goes up easier.
It appears that putting both panels into a suitable weather proof junction box on the roof might be the best.
Thanks Mike for the calculator.
Jonathan, my few cables are multi-tasking, connecting almost anything to anything!The only thing they don't fit is the tv input (lol)
I have 3 similar panels and run individual cables until they get to the hot water service and then I join then in series, to give about 105 volts to the HWS. I also use it to power an electric drill, it will even boil the kettle if you are patient.