About to install my Solar system... I have a few questions.

[One Awesome Inch]

Thanks Chip!

 

[One Awesome Inch]

I just bought a renogy 100w flexible solar panel. I am unfamiliar with the connections on the panel itself... the connecting cables that feed into the charge controller. Is there a specific name for them? Where do I buy the respective connectors?

They look like this...

 

[SternWake]

I just bought a renogy 100w flexible solar panel. I am unfamiliar with the connections on the panel itself... the connecting cables that feed into the charge controller. Is there a specific name for them? Where do I buy the respective connectors?

They look like this...

Those are Mc4 connectors.  I have yet to fondle such a connector.  My PVL-68 came with mc3 connectors.  My Kyocera came with a junction box.

 

[blars]

To avoid buying a special tool to install the connectors, just buy an mc4 extention cable and cut it in half.

 

[One Awesome Inch]

Thanks guys.

So if I buy the extension cable and I cut it in half I can just strip it down to bare wire and plug directly into my charge controller?

 

[akrvbob]

Yes, that is exactly what you do. The MC4 connectors go together and you strip and crimp on a connector to the other end to go to the controller.

Use red electrical tape to mark all the ends of the positive wire or you can easily get confused later.
Bob

 

[One Awesome Inch]

Good idea Bob!

 

[One Awesome Inch]

I have an idea....

Instead of spending close to $50cdn on the needed mc4 extension cable I could omit it. I measured the cables coming off the solar panel itself and they are about 8.5 inches long. Conceivably I could drill holes into the roof of the van in the exact spot, okay over a bit, of the cables and feed them thru the roof/ceiling.

I think 8.5 inches should be long enough. I have 2 inches of insulation in the ceiling and probably a bit more empty space up there. Even if I gave it another 2 inches just to be safe, I would still have about 4 inches left. Since I am stripping the wires anyway I could just do that to the cables on the panel itself once they are in the van.

It would save me about $50 (I have to order it off amazon.ca... more expensive) and I would not have to wait 5 business days for shipping.

Thoughts?

 

[Optimistic Paranoid]

You have to drill a hole in your roof big enough to pass the MC4 connectors through.  How were you planning to waterproof it then?  There ARE ways - see Blue Sea Marine Cable clams - but I'm not sure you will end up saving any money.

And once you have the MC4 connectors inside, how were you going to hook them up to your charge controller?

Remember, if you cut them off, you void the warranty on your panel.  And if you're going to do that anyway, why not just crimp regular wires to it on the roof?

Regards
John

 

[One Awesome Inch]

Not sure if those Blue Sea Marine Cable clams will work for me because of the 4 inches (or so) of material between the outside of the van on the roof and the inside on the ceiling. Plus I'd need two of them and thats close to $60 cdn when all is said and done. I think I'm just going to stick with rubber grommets and dicor. Its cheaper and I found an RV shop locally that sells dicor for a reasonable price.

The idea here is I would cut the ends of the cables off *before* entry in the van, therefore keeping the holes in the van's roof smaller in circumference. Then once in the van, I'd strip 1/2 to 1/4 inch off to expose bare wire, grab some 10 gage wire and crimp or solder together. The other end of the 10 gage wire goes into the charge controller.

Crimping on the inside of the roof means that I'd be able to keep the exposed wire away from rain and weather easier. What I could do is drill the holes and take a 8.5 inch wire piece or even a piece of string and see how that measures out. If its good, I could *then* cut the mc4 connectors off and proceed. Good info on the warranty. I hadn't thought of that.

 

[akrvbob]

There are two warranties on solar panels, I don't know that cutting off the MC4 would void the warranty on power production, but it might. It would NOT be worth $50 to me to find out the hard way!!

No way would I ever cut the end off it's MC4.
Bob

 

[highdesertranger]

what brand of panels? call them and ask if cutting the ends off voids the warranty. however if it was me I would leave the mc4 and get an extension for them you can buy them with the connectors only on one end. highdesertranger

 

[BigT]

And if you are trying to use your alternator as well as the solar, that wire will end up being the third wire on your hot post.  It too needs protection with inline fuses, one close to the house battery and one out under the hood where it ties into the charging system.

No kidding?  Two fuses?  I'm glad I read this.  I'm about to run a 17' battery cable from my fuse box's main power terminal (I couldn't reach the alternator) to the rear of the van and connect it to the (+) terminal of the battery.  I didn't realize I needed to run two fuses. 

Any tips on what size wire and fuses to run to a single, Group 27 AGM?  

Forgive me if this has already been answered.  It's late and I'm tired, but I wanted to ask before I forgot where I saw this. 

 

[Optimistic Paranoid]

No kidding?  Two fuses?  I'm glad I read this.  I'm about to run a 17' battery cable from my fuse box's main power terminal (I couldn't reach the alternator) to the rear of the van and connect it to the (+) terminal of the battery.  I didn't realize I needed to run two fuses. 

Any tips on what size wire and fuses to run to a single, Group 27 AGM?  

Most circuits only have one fuse because most circuits only have one power source.  When you hook two batteries together, you now have TWO potential power sources, both of which need protecting.  Using your example, if you only had a fuse on the engine battery, and a short circuit developed 10 ' back, the fuse would pop and protect the first 10' of wire, BUT THE HOUSE BATTERY WOULD SEND CURRENT THROUGH THE LAST 7' OF WIRE TO THE POINT WHERE IT'S SHORTING AND HEAT THAT LAST 7' ENOUGH TO CAUSE A FIRE.   Thus, you have to protect each battery with it's own fuse.

There's a sticky called wire sizes and fuses (or something like that) which has the table of what size fuse to use with each size wire.  For tying two batteries together, I would use not less than 4 gauge wire.  2 gauge would not be overkill, but going up into the "O" gauges (1/0, 2/0, 3/0, etc.) probably would be.  I doubt that most alternators could supply the kind of amperage that needs "O" gauge wire.

Regards
John

 

[Almost There]

OP, thank you for the explanation - I'd often seen the 2 fuse recommendation but never figured out the why of it. It makes perfect sense the way you explained it!