Full solar system install with pictures, tears and all :)

[Dano]

Now when looking at the roof, the antenna is well over to the left. Inside the upper cabinet there is a mounting flange that bolts the cabinet to the roof and is a few inches wide. The distance from side to side between the middle of the crank handle and the edge of this board is 5”-5.5” inches. When you take into consideration the diameter of your hole cutting tool, it gets reduced to about 5” plus or minus so that is the approximate width over I can go towards the middle IF I want my entry gland to be centered on the flat section of the roof.

We know that out top flat panel is right at about 18” wide so if the antenna is 4.25” over and the inner cabinet has about 5” of available width, then 9” over puts us right in the middle of the flat panel for our hole in a perfect world and the wires should come down right behind the front panel on our overhead cabinets.

It will be close but the gland should be centered from side plus or minus and inch or two at the outside. These are just preliminary measurements to get my head around where the hole will eventually will go. It just dawned on me that the angled front of the cabinets will prevent your drill from being 90 degrees perpendicular when drilling from the inside out. You will need to keep the drill away from the edge and in towards the middle in order to keep it square. If you drill down from the roof, then I guess it’s a non issue but I think I’d rather drill up and know I was safely inside the cabinet rather than hoping I was or hitting an edge of the moulding or something like that.

[Dano]

I don't think it will be perfectly centered but I guess that's okay. It might be off by an inch or so but there isn't a ton I can do at this point until super accurate measurements can be taken when the snow is gone! This at least shows reasonably close to where it will be. The 90 degree angle shows the drill potentially touching the angled face of the cabinet and how it is in relation to where the hole can be cut or if it has to be moved outwards so the drill can fit in there. The length of the drill bit will also impact it's ability to get tight to the cabinet.

I've already got a headache

***These are rough estimates only, not to be used as accurate cutting guides for putting holes in your roof just yet!!

Blue's sketch shows a length front to back of 80" total. Both my panels are 66" in total length and with a gap of 3-4" between panels so I can access the edges if I need to, that only leaves about 10" of length to situate the gland up front so the hole had better be accurate!

[Dano]

Here come the salty tears as predicted!

After looking at my panels and their connectors it makes no sense whatsoever to start cutting into the roof!

Photo attached of our original connector on the roof now...

The wiring and connectors out of the panels is 12AWG and the connector on the roof is 12AWG. All I have to do is wire my 3 panels into this connector and I am done. If it’s good enough for the manufacturer to spec 12AWG for the panels, then the same thickness wire to the charge controller will have no appreciable loss or downside. 12AWG is good up to 20 amps with less than 25 feet of length and I am only going 5 feet so feel safe there. My system will only make up to about 12 amps. This does mean leaving the charge controller and wiring in the same place though. I will still look into the wiring upgrade to 8AWG from the controller to the batteries when I get the side panel open and see what’s inside. Will report back on this shortly...

Sorry for all the photos and drawings only to stick what I have but I think simpler is better in this instance and it is certainly easier and less complicated!

[Blue~Go]

Couple of thoughts:

1) Why is it important to have the hole centered on the panels? I usually try to make mine a bit off center, which makes for a neater run of the wiring coming from the panel junction box (it's kind of awkward if that is right above the hole). It also allows the extra wire to lay nicer around the edges of the panel when the panel is down (that is, the extra wire you leave there so you can tilt the panel up for servicing, cleaning, re-bedding gland, or whatever).

If you aren't sure exactly where to drill, but are close, what I would do is drill a very small hole (1/8"). Then when you see where that comes out on both sides, you can adjust the location a bit if necessary since your ultimate hole will be larger.

Another thought is that for mine, I'm placing the hole near the forward edge of the cabinet. Then the wire can come in and run down that forward "wall" of the cabinet. Basically this copies the small hole left over from the TV antenna wire on the other side. That way you don't have to be up against the edge of the cabinet that is angled and is up against the visible living room ceiling.

2) I haven't completely followed what you are doing, but I think you are talking about 300 watts? (2 x 100 and 2 x 50?). With solar it's not about how much amperage the wire can safely carry (i.e. "12 AWG is good for X number of amps") but rather it is all about voltage drop. Voltage drop means you are leaving power on the roof (or in the wires). To my mind, roof space is precious and limited, as are sun hours. I can't see leaving power on the roof just to save using a bit of wire.

Saying the wire was good enough for the manufacturer's slightly misses the point (IMO). They ran plenty of wire that was severely undersized (like, say, the 30' 8AWG wire from the charger to the batteries - woefully undersized). And too, they were talking about a 50 watt panel. Plus they probably had no idea about the very low voltage drop that's good to strive for with solar. Kind of like "well, a Mercury filling was good enough for my dentist in 1998, so let's just re-use it now."

I'm not sure how many panels you are running in to the controller with this wire. Is it 200 watts? (One 100w and two 50w?). So I can't run any of it through a calculator yet.

Will it work if you have voltage drop? Sure. Will you be getting all your power? That requires running a calculation with incoming power plus length of wire plus size of wire.

Last note: If you do re-use that 12AWG fitting from Chinook, I would at least remove and re-bed it. Mine was not leaking, but there's no way I would have re-used it without re-bedding it at 15 years of age, and just a basic plastic fitting. (Instead I removed it and epoxied the opening closed, as it was in an awkward location and undersized for 200 watts.)

There are much better glands you can use nowadays. They also allow you to use whatever wire size you want. Look at the ones from Scanstrut (my personal faves), Newmar, or Blue Sea if you want to see what I mean.

[chin_k]

I think Dano wants to avoid cutting the roof, and use the existing connector there. It is doable, as he explained, if I understand him correctly, to use 12 AWG for 5 feet, with acceptable voltage drop. I would check the assertion on a table, or use the BlueSea Circuit Wizard.

I understand Dano's view, since cutting the roof is a pretty significant thing to do with the rig, and we have to worry about leak and figure out how to seal each hole off. I would prefer not to add more hole to the rig whenever possible, if we can get away with it with a reasonable solution.

There are actually two separate voltage losses here, and I think we need to take both into account. One is from the panel to the charger, and the other is from the charger to the batteries. We can move the charger location between the panel and the battery, and find a spot that minimize the voltage loss combined. Dano try to compensate the avoidance of cutting a new hole by using the existing wiring, and use bigger wires from the charger to the batteries. As long as it is not a fire hazard, and the voltage loss is not that big (combined loss, that is), I think it is a good solution. I would like to see the actual calculation before I say it is a good/bad idea.

[Dano]

Couple of thoughts:

1) Why is it important to have the hole centered on the panels? I usually try to make mine a bit off center, which makes for a neater run of the wiring coming from the panel junction box (it's kind of awkward if that is right above the hole). It also allows the extra wire to lay nicer around the edges of the panel when the panel is down (that is, the extra wire you leave there so you can tilt the panel up for servicing, cleaning, re-bedding gland, or whatever).

It's not, only aesthetically pleasing

If you aren't sure exactly where to drill, but are close, what I would do is drill a very small hole (1/8"). Then when you see where that comes out on both sides, you can adjust the location a bit if necessary since your ultimate hole will be larger.

This would have been my approach

Another thought is that for mine, I'm placing the hole near the forward edge of the cabinet. Then the wire can come in and run down that forward "wall" of the cabinet. Basically this copies the small hole left over from the TV antenna wire on the other side. That way you don't have to be up against the edge of the cabinet that is angled and is up against the visible living room ceiling.

Agreed

2) I haven't completely followed what you are doing, but I think you are talking about 300 watts? (2 x 100 and 2 x 50?). With solar it's not about how much amperage the wire can safely carry (i.e. "12 AWG is good for X number of amps") but rather it is all about voltage drop. Voltage drop means you are leaving power on the roof (or in the wires). To my mind, roof space is precious and limited, as are sun hours. I can't see leaving power on the roof just to save using a bit of wire.

200 watts total (1x100, 2x50). 12 AWG wires from the original connector to the charge controller, 5 feet

Saying the wire was good enough for the manufacturer's slightly misses the point (IMO). They ran plenty of wire that was severely undersized (like, say, the 30' 8AWG wire from the charger to the batteries - woefully undersized). And too, they were talking about a 50 watt panel. Plus they probably had no idea about the very low voltage drop that's good to strive for with solar. Kind of like "well, a Mercury filling was good enough for my dentist in 1998, so let's just re-use it now."

I meant the wires installed by Renogy on the new panels, they too are 12AWG

I'm not sure how many panels you are running in to the controller with this wire. Is it 200 watts? (One 100w and two 50w?). So I can't run any of it through a calculator yet.

Will it work if you have voltage drop? Sure. Will you be getting all your power? That requires running a calculation with incoming power plus length of wire plus size of wire.

Will still try to run 8AWG from the controller to the batteries

Last note: If you do re-use that 12AWG fitting from Chinook, I would at least remove and re-bed it. Mine was not leaking, but there's no way I would have re-used it without re-bedding it at 15 years of age, and just a basic plastic fitting. (Instead I removed it and epoxied the opening closed, as it was in an awkward location and undersized for 200 watts.)

Will seal it thoroughly for sure

There are much better glands you can use nowadays. They also allow you to use whatever wire size you want. Look at the ones from Scanstrut (my personal faves), Newmar, or Blue Sea if you want to see what I mean.

[Dano]

I think Dano wants to avoid cutting the roof, and use the existing connector there. It is doable, as he explained, if I understand him correctly, to use 12 AWG for 5 feet, with acceptable voltage drop. I would check the assertion on a table, or use the BlueSea Circuit Wizard.

I understand Dano's view, since cutting the roof is a pretty significant thing to do with the rig, and we have to worry about leak and figure out how to seal each hole off. I would prefer not to add more hole to the rig whenever possible, if we can get away with it with a reasonable solution.

There are actually two separate voltage losses here, and I think we need to take both into account. One is from the panel to the charger, and the other is from the charger to the batteries. We can move the charger location between the panel and the battery, and find a spot that minimize the voltage loss combined. Dano try to compensate the avoidance of cutting a new hole by using the existing wiring, and use bigger wires from the charger to the batteries. As long as it is not a fire hazard, and the voltage loss is not that big (combined loss, that is), I think it is a good solution. I would like to see the actual calculation before I say it is a good/bad idea.

Exactly Chin. The only appreciable loss at this point is running the new panel wiring through the original connector, 5 feet to the charge controller. To do this necessitates leaving the charge controller in it's original location as Clay has so successfully done. Then, 8AWG round trip to the batteries and back. Any loss will be minimal and is acceptable to me all of a sudden considering the convenience of re-using what is there. I CAN see the logic of upping my wire to the batteries since I will have to take off the side panel which hides all the wiring anyways. This is the longest run and will be the one to benefit most from an upgrade.

[chin_k]

I am pretty much sold, but I think you should still do the calculation for the whole run and see if you can convince yourself (and Blue) that it is acceptable compromise.

(You can tell that I am just going to copy your homework )

[HoosierB]

I am pretty much sold, but I think you should still do the calculation for the whole run and see if you can convince yourself (and Blue) that it is acceptable compromise.

(You can tell that I am just going to copy your homework )

I'm looking over your shoulder as well.

[Dano]

Stalkers!