Too much cable
- Thread starter Poolboy
- Start date
MisterSandals
Participation Medalist
I'd do anything else before having to put new, possibly problematic/incompatible MC4 connectors on.
SunDave
Solar Wizard
Fully agree with Mr.Sandals here. I coiled them. Used a combo of stainless steel clips, zip ties, and stainless steel zip ties. All UL listed. I would rather have a little extra cable than take the chance of all the new terminations without an issue.
fortunately, the panels I got only have 250-350mm of cable length, just enough to connect the next string in series with almost no slack.
DPC
Canada, Great already
Can you show some picture of incompatible MC4 connectors?
I thought they are all the same?
MC3
MisterSandals
Participation Medalist
dustyPanels
New Member
My REC panels had reusable zip ties on the cables. So I reused them.
Yes, coil them up and tuck them so they are not dangling. I only have 3 x 100W panels so it's not too bad.
SunDave
Solar Wizard
There are stainless steel clips that attach to the bottom lip of the panel frame and hold wiring. Those were nice.
I used a combination of attachments so that the sun doesn't destroy them all in a year or two. They are on the non-sun side, but I'm hoping the clips, the UV resistant plastic zip ties, and the stainless zip ties used on the ground wires hang in there for the long term. I think having more than you need will be key if you don't want to be messing with it in a couple years.
I used a combination of attachments so that the sun doesn't destroy them all in a year or two. They are on the non-sun side, but I'm hoping the clips, the UV resistant plastic zip ties, and the stainless zip ties used on the ground wires hang in there for the long term. I think having more than you need will be key if you don't want to be messing with it in a couple years.
Koyaanisqatsi
Electron addict
NO COILS IN YOUR DC WIRES!
No circles or loops at all! (collectively referred to as loops). Run the wires straight out and then back to where you want them, making sure that they are kept parallel, "S" shaped or "U" shaped. Keep your positive wires as close to your negative wires as possible - bundle them together. And make sure you do not create a giant loop by running your positive to one end of the array, and your negative around the other side of the array to the other end. Pos and neg should always be bundled together. And interconnects must be un-looped and run out and back in a "T" shape. Use frame clips and/or zip ties to keep wires close to each other.
Loops are inductors that can act like a transformer or antenna and pick up stray electrical noise. It can introduce high voltage spikes into your DC system. It can burn out MPPT inputs and/or make your charge output unstable. If lightning strikes a few miles away, it can induce huge voltage in your PV wires if there are loops in it, and blow things up in a jiffy
Uncoil all wires and lay them out straight, then fold them back to where you want. If you can handle the work, clip the connectors and extra wire off and crimp new connectors to the shortened leads.
The PV wires running back to the house should always remain bundled together. And whichever one runs out to the far end of the array should follow the path of the wires and MC4 connectors between the panels. Literally zip tie it to them.
This is also true for your battery and inverter DC cables. Pos and Neg should be bundled together and kept parallel wherever possible. It improves surge handling and reduces noise from your own wires that gets created by the inverter. Never loop the extra wire, if your battery cables are long on some of your batteries. Lay (stuff, cram, jam) them into a "S" shape.
No circles or loops at all! (collectively referred to as loops). Run the wires straight out and then back to where you want them, making sure that they are kept parallel, "S" shaped or "U" shaped. Keep your positive wires as close to your negative wires as possible - bundle them together. And make sure you do not create a giant loop by running your positive to one end of the array, and your negative around the other side of the array to the other end. Pos and neg should always be bundled together. And interconnects must be un-looped and run out and back in a "T" shape. Use frame clips and/or zip ties to keep wires close to each other.
Loops are inductors that can act like a transformer or antenna and pick up stray electrical noise. It can introduce high voltage spikes into your DC system. It can burn out MPPT inputs and/or make your charge output unstable. If lightning strikes a few miles away, it can induce huge voltage in your PV wires if there are loops in it, and blow things up in a jiffy
Uncoil all wires and lay them out straight, then fold them back to where you want. If you can handle the work, clip the connectors and extra wire off and crimp new connectors to the shortened leads.
The PV wires running back to the house should always remain bundled together. And whichever one runs out to the far end of the array should follow the path of the wires and MC4 connectors between the panels. Literally zip tie it to them.
This is also true for your battery and inverter DC cables. Pos and Neg should be bundled together and kept parallel wherever possible. It improves surge handling and reduces noise from your own wires that gets created by the inverter. Never loop the extra wire, if your battery cables are long on some of your batteries. Lay (stuff, cram, jam) them into a "S" shape.
Koyaanisqatsi
Electron addict
Another discussion on the issue of loops: https://diysolarforum.com/threads/i...s-why-havent-i-heard-about-this-before.91643/
SunDave
Solar Wizard
I believe this is one of those times that theory is one thing, and the reality of a situation is another.
In theory, solar panels shouldn't be outside because they are degraded over time by UV. In reality, if they were not outside, we wouldn't make power from them. I know it is an extreme example, but just an illustration of how far it can go. I personally don't worry about a couple loops on the back of a panel.
Oh, wow. I did not know this. Thanks!
Three cheers for being lazy and strewing them about randomly on the roof!
I find creative ways to take up the slack. I would rather have some slack now in case something changes later and I need the cable longer.
I use the clips that attach to the underside of the panel frame. They can be a PITA to install on the frame, but that's a good thing.
I use the clips that attach to the underside of the panel frame. They can be a PITA to install on the frame, but that's a good thing.
DPC
Canada, Great already
I want to say shorten the cables.
I suspect some people are concerned they can't make a new connection as good as the factory produced wires harness.
I suspect some people are concerned they can't make a new connection as good as the factory produced wires harness.
DPC
Canada, Great already
Bigger the transformer the fewer the turns.
One of the reasons we prefer the Delta connection on large 600 volt motors is to get more turns in the coil groups, and we can put a finer point on the core flux density than sometimes a Y connection.
I had to think about this one.
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