Chinook RV

Blue~Go wrote: March 16th, 2019, 10:53 am

HoosierB wrote: March 16th, 2019, 9:20 am Will I be able to use the old passenger side and antenna access holes for routing to an interior cable connection/junction box (in the overhead cab)... then on to the controller in the storage compartment next to the batteries?

Can you say this a different way? I'm not sure I understand what you are asking.

Something like this?....

Okay, I'm looking at this now. BTW, I added something to the last post (but now it looks like you had already read it) addressing mixed panel sizes in series. But let me look at this diagram and see if I understand the question now.

*******

Okay, back. The problem with the layout shown (if I'm seeing it correctly) is that you have a 100 watt panel in series with a 50 watt panel, and then that set in parallel with another set of the same construction. But you don't want panels of mismatching amperages in series with each other. If all four were 100 watt panels then it would look fine.

If you put the two 50's in series and the two 100's in series and then those two sets in parallel that would work, but that's a lot of extra wiring, some having to go across the ocean (middle of the roof). If you put the two 50's in parallel and then that pair in series with each of the 100's separately in series that would work, but then you get really high voltage which is a big pain because many switches and breakers (and some controllers) won't handle it. I like to stay below about 35 volts vmp, which will still be below a 48v rating even at open circuit on a cold morning (many things are rated to 48 volts).

So I guess you have to have 400 watts Or 200. Or change the wiring scheme.

Here are the two options I considered. I chose the one that adds a bit more wire and one more roof hole (with proper gland ) , but allows for a better roof layout. (Note that I still end up with fewer holes than original, and the disused ones are closed with epoxy (added cloth if size calls for it). Heck the stock TV antenna had like 12 holes into the roof! And don't even think about that railing around the perimeter...

I couldn't find any nice way to put a big ol' junction box on the roof, so my plans have always included a junction area inside the cabinets instead. That's okay though as I can have a shut off there as one of the posts.

1) Two 100's in series on the passenger side, and two 100's in series on the driver's side. All four resulting wires go down through a Newmar DX-5 gland through the old antenna rotator hole (the bigger hole). DX-5 gland was chosen because it works with that hole (most glands are too small for that), is good quality, and lets four wires through easily. You do have to make sure you have room for the vertical "shepherd's crook" of the wires above the gland and under the panel. Then on the forward inside "wall" of the cabinets over the couch, they have their junctionage, and one larger duplex wire runs out into the wire chase, behind that little patch of wall into the overcab, and down the pillar and to the controller under the couch.

What I didn't like about that was that if I had wires going over the roof inboard of the panels (to get from passenger side to driver's side), I had to space the whole panel further out (more overhang) just to accommodate one dang wire. If I ran the wire back and over the roof at the junction between the two panels (so they could again snug up to the roof) then that was right by the air conditioner hole so the wire would have to go way back and around the back of the AC and etc.. Ugh.

2) Is how I'm planning on doing it. Same panels and same series/parallel connection but run each set down through its own gland on its own side, and then the passenger side wire comes across hidden in the overcab and both that wire and the one from the driver's side go down the pillar and join by the controller.

Advantage is that both panels can snug up to the roof. No wires scraggling across the hump. I can use the right angle glands (Scanstrut DS-H10) which have no "shepherd's crook of wire." Ahhh. But of course nothing is perfect. Disadvantages: Wire run from passenger side is a little longer, and also the horizontal glands never take very large wire (like the DX-5 will). And they like round wire. I happen to have a bunch of 12AWG duplex round so that's fine. But it will be a little more fiddling as I will have a 10AWG joiner between the forward and aft panel MC4's, then 12AWG going through the roof (to use the round wire), then will transition in the cabinet to larger wire to go across the entertainment center and down the pillar. But that can incorporate my shutoff for each side at that inside junction, so not all bad. And there is a pre-cut round gland insert with the DS-H10 that just fits the round 12AWG Ancor duplex.

Blue~Go wrote: March 16th, 2019, 11:28 am 2) Is how I'm planning on doing it. Same panels and same series/parallel connection but run each set down through its own gland on its own side, and then the passenger side wire comes across hidden in the overcab and both that wire and the one from the driver's side go down the pillar and join by the controller.

Advantage is that both panels can snug up to the roof. No wires scraggling across the hump. I can use the right angle glands (Scanstrut DS-H10) which have no "shepherd's crook of wire." Ahhh. But of course nothing is perfect. Disadvantages: Wire run from passenger side is a little longer, and also the horizontal glands never take very large wire (like the DX-5 will). And they like round wire. I happen to have a bunch of 12AWG duplex round so that's fine. But it will be a little more fiddling as I will have a 10AWG joiner between the forward and aft panel MC4's, then 12AWG going through the roof (to use the round wire), then will transition in the cabinet to larger wire to go across the entertainment center and down the pillar. But that can incorporate my shutoff for each side at that inside junction, so not all bad. And there is a pre-cut round gland insert with the DS-H10 that just fits the round 12AWG Ancor duplex.

As soon as I posted that last diagram, I realized the mix-matched panels would be a no-no. Decided three identical 100W panels will fit and be cheaper than using the 50W'ers. However, I do lose my "symmetry points"
So, if I understand what you're saying in your second scenario, my new layout idea would be similar except for the "junction box" in the overhead cab... which may not be necessary?

So in your diagram, if I'm reading it correctly, you still have the two 100 watt panels on the driver's side in series. That won't work because it makes another mismatch: two 100 watt panels in series, parallel connected to one 100 watt panel. Same problem as before. I see a few logical choices:

1) Run all three 100 watt panels in parallel.

Advantage, all the same.
Advantage, shaded panels won't bother other ones (although it takes absolute blocking shade to do that, not little strings or branches in my experience).

Disadvantage you will need larger wires, and you almost do need a junction box on the roof because you will have six wires coming off the panels (one positive and one negative from each panel). I guess you could cram six wires into a DX-5 (maybe?)
Disadvantage, I think you then need fusing between the panels when more than two are in parallel (I used to know exactly why, but since I never have more than two panels in a unit, I was able to forget).
Disadvantage, perhaps a bit less early and late day power harvesting (not sure this is enough to be a solid disadvantage).

2) Go down to two panels, then run them in series or parallel, as it suits you. Put them both on the same side and you can have one "beauty side" with nothing
Advantage, less expensive
Advantage, only two panels to bracket and attach
Advantage, space for a patio up there where the other panels would have been.

Disadvantage: Only 200 watts, which when it is flat on the roof is not much during poor sun times (late fall/winter/early spring)(partly cloudy day).

3) Run all three in series
Big disadvantage, that's like 75 volts which will make you buy specific switches, breakers, and controller that can handle them.
Advantage: You could wire them with dental floss at that voltage

4) Go for four 100 watt panels, and do two series pairs (same plan as I outlined).
Disadvantage, you may not need or want 400 watts. I can already hear it "Less power, we want LESS power!" Ha, just kidding, because if you don't need it, you don't need it.

5) Two 100's on one side, and two 50's on the other side, then make each side a series pair.
Advantage, save some space over four 100's
Advantage, 300 watt sweet spot you already determined was good.
Advantage, series pairs are nice (only four wires coming in, two on each side of the hump, no need for exterior junction box).
Disadvantage, 50-watters are more expensive per watt, but you were already buying two anyway.

6) Mount two 100's on the roof, and then carry two 50's as ground panels (these will store between the driver's seat and the couch, at least in my Chinook with stock Flexsteel seat and stock couch frame - I don't drve with the seat way back but I could check if you would like (I carry two 100's there - 50's would tuck nicely down whereas the 100's stick up).

Advantage: Ground panels always face the sun, at the right angle, even when you are cooling the Chinook in the shade. This can be especially nice if you are not tilting roof panels. I think it's why my 200 watts have done so well for me (combination of very minimal voltage drop, good controller, and they are tilted to face the sun angle).

Disadvantage: you have to carry them inside and place them outside.
Disadvantage: A bit more wiring (but not on the roof, and less faddle on the roof with only two roof panels).
Disadvantage: You would either need to put the roof panels in parallel, and the ground panels in parallel (boo), or you would need two controllers. OTOH, some people feel that two controllers is good so that each panel or set of panels can do its best. Some of the small MPPT controllers are quite affordable now (example: Victron 75/15, which has a nice bluetooth reader, and can integrate with their battery monitors).

Blue~Go wrote: March 16th, 2019, 5:03 pm 4) Go for four 100 watt panels, and do two series pairs (same plan as I outlined).
Disadvantage, you may not need or want 400 watts. I can already hear it "Less power, we want LESS power!" Ha, just kidding, because if you don't need it, you don't need it.

This one is interesting, because of the additional power (primarily for my Virtrifrigo AC/DC fridge). How would four Renogy Compact Design 100W panels position on the roof?

HoosierB wrote: March 16th, 2019, 7:02 pm This one is interesting, because of the additional power (primarily for my Virtrifrigo AC/DC fridge). How would four Renogy Compact Design 100W panels position on the roof?

Very nicely, at least on my roof.

Width-wise, they are 19.5" wide (they say 19.6" IIRC, but mine actually measure 19.5"). The only narrower panels I have found are the ones that are 13" wide, and then you really use up a lot of space for fewer watts because you are not using the full cake tier width. Length is 42.5".

I placed two near the forward end of the tier, but with a couple-few inches just so they wouldn't be RIGHT at the edge. Then 3" or so between sets. The rear set easily clears the bathroom skylight with plenty of extra room so that lid being open won't throw shadows unless a very low sun angle. On the driver's side, the rear/outboard foot will overhang the forward end of the refrigerator vent. So that foot would need to be mounted further inboard. The vent (on mine anyway) does not stick up above the roofline. Since we are not burning fires in there, I don't think the slight obstruction matters (might not matter with an absorption fridge either for that matter).

The joint between the forward and aft panels is alongside the Air-con unit, which is why it's awkward to run the wire across the roof (unless you space the panel out from the upper tier to accommodate the wire, or run it way around the back or around the front of the main roof vent), so that's why I decided on running each side into the cabinets on its own. Plus I like those horizontal glands as the entry doesn't face upward.

There is a good 30" from the aft end of the passenger side panel to the place you get onto the roof from the ladder, so that's nice.

[Edited to add that one could put one across the back from the bathroom vent to the ladder area, although you'd have to have a really specific reason to do that as it would block easy ladder access. Also perhaps one aft of the air-con. If there were a reason to avoid one side. I think it'd be a titch awkward though.]

Possible issues:

-- If you still have the Air-con (and being in Indiana I hope you do!), then that can shade panels that are next to it, and that's a blocky sort of shade (not thin or filtered like a leaf or branch). It's not likely the sun would be coming from both sides at once, so I think you would be most likely to get shade on only the driver's or passenger side, but not both at the same time. So even with series pairs, you should always have two running at peak capacity. And one of the others may at least be helping.

-- Don't know what if anything else you have up there. The Fantastic lid could maybe throw shade on them, but that would probably be on the same panels as the AC.

The conventional wisdom says to do parallel panels if you might have some shading. I'm not saying that's wrong, but I think there may be a case for series/parallel. The idea is that if one of a series pair is shaded, they both go down. I did some experiments with two 135 watt matching panels in series lying flat on the ground (to simulate roof mount). This was in full sun, mid-day, in August. I had them hooked up to my known solar controller and display plus battery monitor. I ran some good-sized loads so that the panels would be asked to give their full possible output.

No shade at all, my controller was putting out the full 15 amps it is rated for (the panels could technically put out about 16 amps). Then I started putting up some branches (wispy shade) about five feet above them. They still maintained pretty well (I could go back and look for exact figures as I photographed my gauges throughout). One panel was reduced, but I never "lost" more than half (one panel is half) and not always that much. Same with shadows cast from leafy branches 75' over the campsite (I kept experimenting as the sun went behind some tall deciduous trees). The only time I saw output reduced more than half (i.e. the one shaded panel PLUS most of the other one that wasn't shaded) was when I covered some cells of one of the panels with cardboard, so they were 100% blacked out. That did some damage. Those the results would have been better in parallel.

So what does one gain by going in series, since you might be giving something up in certain partial shade situations?

Well, you get to run thinner/smaller wire for the same voltage drop. You only have two wires coming off of a set of two panels vs. four. It is said that they start producing better/earlier and keep going better/later in the day due to the higher voltage. I haven't done any experimenting with parallel to see if it is true or how much. If you have ground panels series is definitely best because you can have say a 35' wire to get the panels in the sun and it doesn't have to be a tree trunk (or heck, use a tree trunk and put them a half mile away ). Also there is something about having more than two panels in parallel that requires different fusing, but I forget what. Something about the power from two panels going into one of there is a problem, I think...?

With PWM controllers you really couldn't do series, so I think that may be part of the reason for the parallel habit. Not that parallel is bad. I'm doing a parallel installation on a boat that has SO MANY shade makers that the panels will nearly always be partially shaded with blocky type objects (waaah).

MPPT controllers can make use of the "head" of higher voltage. Some are most efficient at say 20 volts, some at 35, etc. But all of them can "down convert" to the battery voltage and make use of all the power (PWM doesn't do that in the same way as MPPT). MPPT have come down enough in price that it makes an easier decision as well, IMO.

So I can't say definitely one way or the other, but I will be hooking my four panels up as series pairs, and unless I see some major problem won't change to parallel. I hope I didn't forget anything here. Starving and waiting for pizza to be done

PS: Dano, just let us know if you want your thread back at any time

Alright, what a day and a full day at that! Started out as solar only but ended up re-doing one of the biggest jobs I had already done and I am so glad I did it!! In order to re-install the side panel, you will DEFINITELY need to have drivers seat out. Getting the edge behind the wall panel took a lot of effort and a lot of angles to get it to go but I eventually got it but having the seat out was a necessity.

To take a detour on the solar install for a second...I had originally done a tutorial on replacing the front carpet. Well it didn't match the new main Coach carpet and it irritated me so I went the extra mile and pulled out the passenger seat. Within 3 hours, I had removed the console, doghouse wheel well side trim step plastic covers and all the carpet. I had enough leftover from the Coach to cut an entirely new piece but had to rent a carpet seam iron to attach two small pieces which I did. After that was re-installed, I nailed down the front edge of the carpet where the Coach carpet meets the front cockpit carpet. Easy to do with the seats out, a bear to do with them in. Anyways, a huge job but now it all matches and is perfect.

Back to solar! Before re-installing the side panel, I drilled a hole through the floor right behind the low voltage disconnect but still hidden inside the side panel. I routed my two solar 8AWG wires up the side and into the bulkhead. The wires exit perfectly at the battery box and I will drill two holes into the box and will add rubber grommets around each wire. Trying to pull the wires through the original hole that has all the other wires was too tight, this will make my life so much simpler! Running it up top into the overhead cabinet was not much trouble at all.

So, net result? Solar panel access holes drilled, wires pulled through the cabin, side panel re-installed, new carpet cut and re-installed!

Next up will be fixing the solar wires across the top in the overhead cabinet, enlarging the charge controller opening so the new one fits and then getting rid of some snow so I can start the panel install up top. 3M VHB tape just arrived for the bracket install...getting CLOSE!

Blue~Go wrote: March 16th, 2019, 8:30 pm PS: Dano, just let us know if you want your thread back at any time

BG: Sent you a PM