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  • #61
    Does it matter where I combine a string? I wouldn't think so, but would it matter if I interconnect the 2 panels in the combiner box? or does that have to be done close to the 2 panels?

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    • #62
      Originally posted by -TX- View Post
      Does it matter where I combine a string? I wouldn't think so, but would it matter if I interconnect the 2 panels in the combiner box? or does that have to be done close to the 2 panels?
      To keep the voltage drop as low as possible you usually combine the panels as close to each other as possible. Then you can use smaller wire size for the longer runs because you have now "doubled" or increased the string voltage and minimized the 2% VD on that wire. That doesn't mean you couldn't combine them farther apart.

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      • #63
        Yes it matters. As SE elluded to it is about controlling Voltage losses and keeping them low as possible. This is why you use MPPT controllers so you can wire the panels in series to get the voltage up and current down. When you wire the panels in series, you keep the factory panels wire short, and if you plan it right and keep parallel strings to 2, you eliminate the need for a combiner and fuses.

        With an RV life is fairly simple as no wire runs are really long. Your goal is to keep the voltage loss to 2 to 3% or less between panels/controller, controller to battery, and battery to Inverter or load devices. .
        Last edited by Sunking; 03-17-2017, 04:30 PM.
        MSEE, PE

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        • #64
          Runs are 10 and 15'. 16awg well within those limits. I'll take your answers as a yes. Thank you for answering.

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          • #65
            16 AWG wire?

            [ Mod note - this flagged post is rude ?
            16 AWG wire?
            My only response as a moderator is stay far north in the permafrost zone so your precious snowflake self won't melt. The [S] fun [/S] hazing here never stops ]
            Last edited by Mike90250; 03-18-2017, 11:37 AM.
            MSEE, PE

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            • #66
              Yup, short run I cut up an old 25' extension cord for. God forbid!

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              • #67
                Sunking, as long as you don't say YES, Go Ahead, your butt is covered.

                TX, - seriously? cutting up old ext cords for your premises wiring ? So you have checked the 2 way run length against a voltage drop calculator. and 16 ga passes at less than 3% drop. You are well out of established practice here, and maybe just jerking SK''s chain. Ext cord has no thermal rating, 1 little hotspot will burn through, along with any pressure points pushing through the insulation over a years time. All appearances aside, we really don't want to read about another solar induced fire and fatality in the news.
                Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                solar: http://tinyurl.com/LMR-Solar
                gen: http://tinyurl.com/LMR-Lister

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                • #68
                  Dude, it's a 10' run that is all inside and will support voltages 1/5th of its AC rating, and fused. It's fine. All the other wiring is premium stuff.

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                  • #69
                    Rude? How was that rude?

                    If I had to guess the panel factory wires are 14 AWG and ought to tell you something. What is the panel Isc and Imp ratings and how many parallel strings are you using?

                    Tell you what, I have a few reels of what Teloco's call Cross Connect wire, 24 AWG, color coded, 2-pair wire I will let you have and you can use it between the battery and Inverter. You can use a pair of pliers to crimp terminals on if you want or no terminals at all. Just wrap the wire around the set screws.
                    Last edited by Sunking; 03-18-2017, 12:16 PM.
                    MSEE, PE

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                    • #70
                      Originally posted by -TX- View Post
                      Runs are 10 and 15'. 16awg well within those limits. I'll take your answers as a yes. Thank you for answering.
                      And look, there is a 100 A fuse protecting that 16 awg. This is one of this most ridiculous posts I've seen in a while... I hope you've just decided now that your system is done, it would be fun to troll some of the other members.

                      For those who might be taking the post seriously... How do you put 20+ A (Topoint 190's are 5.8 A Isc) though 16 awg and get an acceptable voltage drop, let alone comply with the ampacity tables? Care you show your work?
                      Last edited by sensij; 03-18-2017, 12:55 PM. Reason: looked up panel specs
                      CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

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                      • #71
                        Originally posted by sensij View Post

                        And look, there is a 100 A fuse protecting that 16 awg. This is one of this most ridiculous posts I've seen in a while... I hope you've just decided now that your system is done, it would be fun to troll some of the other members.

                        For those who might be taking the post seriously... How do you put 20+ A (Topoint 190's are 5.8 A Isc) though 16 awg and get an acceptable voltage drop, let alone comply with the ampacity tables? Care you show your work?
                        See Sensij we agree more than we disagree. You know as well as I do there is no configuration he could possible come up with stay within acceptable and safe limits with 1900 watts of panels. He just does not understand or wants to understand. I agree this is just plain ignorant and you cannot protects people from themselves. I have been very patient with TX. I have gone over the math with him a dozen times and it is not getting through to him.

                        MODS you know darn good and well this guy is building a Fire Trap. Might I suggest you shut his threads down in the interest of public safety. He is just not getting it after being told and shown a dozen times. We just cannot help this snowflake playing with fire
                        Last edited by Sunking; 03-18-2017, 04:42 PM.
                        MSEE, PE

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                        • #72
                          Yeah, I just don't get what he's doing with wire, terminations, and OCPD. That is usually the most important thing to get right, for safety.

                          At least the charge controller is a good match for the panels.

                          tx.JPG
                          CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

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                          • #73
                            Originally posted by sensij View Post
                            Yeah, I just don't get what he's doing with wire, terminations, and OCPD. That is usually the most important thing to get right, for safety.
                            I am certain you will also agree for performance. Not like it is hard either. Only two conditions need to be met and with this chart makes it super simple.

                            1. The wire must be large enough, with the proper temp rated insulation to OCPD it is connected to. That takes care of safety side of things.
                            2. To meet performance requires controlling voltage drop to 3% or less. Once you get more than say 5 to 6 feet means the wire will has to be larger than the minimum safety requirement.

                            So if you use this Chart makes it fool proof and simple. The smallest wire for 20 amp breaker is 14 AWG with 105 degree insulation, but that only goes ott to 6-feet one-way distance to met 3% or less voltage drop. 7 to 10 feet requires 12 AWG, and 11 to 15 feet is 10 AWG. That is what the chart is there for, to make it easy to KISS

                            So at 20 amp OCPD with 16 AWG does not even meet minimum safety requirement. At 15 feet one-way is laughable performance. It meets no objective.
                            Last edited by Sunking; 03-18-2017, 07:35 PM.
                            MSEE, PE

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                            • #74
                              OK then, seems like this thread has run its course and I think its an example of "you can lead a horse to water but you cant make him drink" some folks dont take safety and doing things to code seriously and that is well just stupid, ignorant and selfish. Electricity can and will KILL you if you are stupid enough, if your lucky it might just burn down your house with no fatalities. So anyone unfortunate enough to read this thread take it as an example of what NOT to do. Closed, goodbye TX

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                              • #75
                                Originally posted by -TX- View Post
                                Dude, it's a 10' run that is all inside and will support voltages 1/5th of its AC rating, and fused. It's fine. All the other wiring is premium stuff.
                                Why would anyone in their right mind be so foolish to insist on using 16 gauge wire for this? Cant be a money saving move. I think TX was either looking for an argument or too dense to get it.
                                2.2kw Suntech mono, Classic 200, NEW Trace SW4024

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