Solar

[Blue~Go]

I don't have a tow car. In my previous rig (which had a compressor refrigerator) I had to keep a move on because I had no other way to charge. Thing is, unless you have some super-duper B2B type charger, an hour or two running errands doesn't help that much. Reason is the alternator is not a very good charger as applied to an RV house bank. It does work, and especially on a "road trip" where you are mostly driving at highway speed for hours on end with relatively short stops. But a short trip to town... not so much. (By B2B charger, I mean something like a Sterling battery-to-battery charger which is a thing that basically turns your alternator into a smart charger.)

I have a more "big, permanent" solar system in the works, but in the meantime, I put in a "mockup" system (by now you know I love my mockups ) and it's working really well! Basically, I have two 100-watt semi-flexible panels and a small (200-watt maximum) solar controller. When driving, the panels live in their original box right behind the driver's seat, between it and the end of the couch. Not too much in the way (although I'm not 6'4" or anything). I ran a ~30' #8 duplex wire from the charge controller into the compartment on the side of the rig where the shore power cord lives, and terminated it with MC-4 plugs. I filed down the prongs so they are a tight friction fit but don't need the tool to do/undo. If I'm driving a lot (road trip), the alternator plus the 50-watt panel pretty much take care of things. If I'm parked for more than a day, I put the panels out in the sun (tent stakes in the corner grommets) and plug them into the #8 cable. (I have them in series, so just connect one wire from each panel together, then the other two into the #8 cable.)

Of course this is a bit more hassle than having panels on the roof, but it's working great for now (and I already had the panels and controller from another project). If I'm stationary for more than a day I can put the panels out (in most locations); if on the move, no need. They take up no room on the roof and needed no mounting. Side bonus is I can park in the shade but put the panels in the sun.

I just spent 14 days in one place and had the panels out. They were in full sun after around 10 a.m., and granted it is right around mid-summer so best case scenario. I was running a small compressor cooler (52 liter, draws a bit under 4 amps) 24/7 plus charging laptop, phone, etc. Batteries were at 100% every day. I can't tell exactly how many amps I could have taken in (because if the batteries are full and there are no big loads, then the panels "hold back"; but the most I took in in one day was about 56 amp hours. Most days were in the 35 amp range.

I still think a roof system has a lot to recommend it, and I will likely go ahead with mine; but this was an interesting experiment and I think could be a good alternative for certain people/travel styles. One thing I wanted to find out was how I would do running the refrigerator with 200 watts. Reason is that if I go with panels that overhang the second roof tier I can easily fit 470 watts. However with panels that are completely "inboard" I can fit 350 watts without undue strain. I was interested to see how 200 watts will fare. That said, in some ways it was a "bad" experiment, because it was mid-summer and not cloudy. OTOH, it was hot (refrigerator). My "real" refrigerator will be larger, but maybe not use much more power due to better insulation than the cooler-shaped one.

These panels are already showing signs of cupping, which is one of the downsides of the semi-flexible panels, however you can't beat them for lightness if you are going to be moving them around. I simply accepted when I bought them that they were going to be much less long-lived than aluminum/glass panels. I imagine that will change as things continue to develop.

For anyone interested, the equipment I am using at the moment:

A) Two Grape Solar 100-watt semi-flexible panels, wired in series (@35 volts).
B) Morningstar Sunsaver 15 MPPT controller with RM-1 remote display.
C) Balmar Smart Gauge.
D) Lifeline AGM batteries with appropriate fusing/switch/fuse block/etc.

I have the above set up independently of the Chinook system for the experimental period. What I mean is that the Chinook system is still "as-built," with just one Group 27 flooded cell down in the battery compartment (although there is of course room for two).

For the "mockup system," in addition to the above items, I simply have two cigarette sockets, each on its own circuit with #12 wire. Into these I can plug the refrigerator (it has a cigarette lighter type end), or any of my personal electronics (computer/iPad/phone/AA battery charger, etc.). I used that when I had the solar panels out. On the road I switch those things over to the Chinook sockets, which are then charged by the alternator/50-watt panel. It's given me some interesting data, which was the point (also, I was going to be off-grid for a couple of weeks, and wanted some decent charging power).

[HoosierB]

Adding to my list is the solar upgrade. Being "electrically challenged", I'm researching as much as possible with this site being the most helpful, and a couple others (blogs) having done conversions as well. One issue for the Chinook seems to be the roof "overhang" of the much larger and more efficient panels that are available today. I came across this site because of the "slim width" of their panels... 13.5", which I believe is close to the original width of the Siemens panel installed by Chinook. The installation of the two panel kit at 160 watts seems doable with a 240 watt 3 panel kit being questionable due to the overall length of 116" with two panels together (58" each). They also offer a 40 x 20" panel which doesn't seen too bad overhang wise and may offer more options for install. I also plan on removing the TV antenna for my upgrade, but have not ventured up on the roof yet to take any measurements. Open to any opinions, comments, observations or alternative suggestions...

https://back-countrysolar.com/product/a ... 60-watt-l/

[Blue~Go]

I took a quick look at that kit. To me, the price seems a bit high considering that it's only 160 watts with a PWM controller. I agree that "no overhang" panels seem attractive. Along the same lines, I seriously considered the Solarland SLP-70. It's a 70 watt panel that's around 13" wide and 58" long, so would fit completely on the upper side tier of the roof. Without the TV antenna (which I removed as I'm not a TV watcher), I could fit three of them. Two in line on the passenger side, and one on the driver's side (can't fit two due to bathroom roof vent).

So why did I decide against them? They are rather inefficient for their size. By using "modern" panels I could fit 470 watts (if I wanted to) vs. the 210 watts of three of the 70 watt panels. That would be two 135 watt panels, and two 100 watt panels, one of each per side. Or two 100 watt panels for 200 watts, or two 135 watt panels for 270.

Although I'm not super keen on the slight overhang (they don't overhang the outside of the Chinook, just the one tier by about 3"), it galls me to buy expensive, inefficient panels. Another reason for me is that I like to run series pairs (higher voltage gives the controller a bit of headroom, and also allows smaller wiring for the same voltage drop). Two or four panels works well for that, giving a nice voltage of around 34. Three panels in series would require special fuses, switches, etc. (because of the higher voltage) and is up in the less efficient range for many controllers. I also run two 100-watt ground panels, so with the "normal type" roof panels I have the option of just running one controller vs. two.

Also, if anything ever happens to a panel, I like having one that is not an oddball only sold by a few vendors (a friend had this happen with the old AM100 panels that were something like 22-24 volts; one was damaged and he couldn't get a like replacement, bummer).

With two 100 watt panels, you can run them both on one side if desired (keeping the other side "clean"). Or, I considered one on the top tier just behind where the AC used to be (not sure if that would work if you still have the AC due to shadowing), and one crosswise on the roof at the rear just behind the top hump. No overhang at all but would intrude on the "landing pad" getting off the ladder, so I pretty much ruled that out.

I still haven't mounted my roof panels, but I'm pretty sure I'm going to tolerate the slight overhang and go for more efficient, common panels. I'll run them in series pair(s), and that will coordinate well with my series pair ground panels (great for parking in shade, and/or easy placement and tilting on those days you need to squeeze out every last amp - say it's been cloudy for some days).

if you do choose more "standard" panels, I'd recommend the Renogy Eclipse panels. These cost a bit more than their "baseline" 100 watt panels, but the cells are more efficient so they are 32 cell vs. 36 cell. This makes them a tidy 20.7" wide and ~41" long. They are only around 15#. They look to be clones of my Grape Solar 100 watt panels. They also have a voltage (17.x) that is close to that of many other panels (like say the lightweight panels if you choose to run those as ground panels). The cheaper 100 watt Renogy panels are a bit heavier, a bit larger in dimensions, and run in the high 18's for voltage. Nothing wrong with that, but it's nice to keep voltages closer if you are running other panels and the narrower width and length of the Eclipse panels is nice, I think.

I like to run an MPPT controller. First of all, I can run series pairs which has worked well for me (MPPT can down-convert the voltage to the nominal 12 volts our batteries want). And I have seen plenty of times where I was taking in more amperage that I would have with straight PWM. I also like a controller that can be customized to match the batteries, and for lead acid batteries (AMG in my case) temperature compensation on the controller is something I look for. I can see the temp of both my battery bank and the controller, and through most of the solar charging cycle (early morning to afternoon) the battery bank is much colder than the controller, even though they are mounted within 3/4" of each other (controller is mounted to the outside of my battery box, which is 3/4" thick). Since the whole point of a smart controller is to provide the correct voltage, and since voltage varies with any temperature over or under 77ºF, I couldn't see having a smart charger but then not having temp comp.

At the moment, with just my ground panels, here is a synopsis of my setup (in case this helps you vs. all the blathering above )

1) Two 100 watt solar panels set up in series (so around 35 volts)
2) 35' of 8AWG Ancor duplex wire
3) Morningstar Sunsaver MPPT 15 amp controller (with temp comp and RM-1 remote meter)
4) Short length (under 12") of 2AWG wire from controller to positive bus (could be 6AWG).

Working the opposite direction, I ran the wire from the controller along the couch wall into the box that holds the shore power cord. I put two MC-4 connectors on the free end of that wire (the 8AWG duplex). When the panels are not deployed, the wire is coiled up in that box. When I go to deploy the panels, I bring the wire out through the "mouse hole" and to the panels.

As with many of my systems, I start with a "mock up" setup and try it for awhile. In this case I'm glad I did as I've had ample power with just the 200 watts. I had planned to put 470 watts on the roof, but now see that would be overkill for my needs. I will put 200 watts or so on the roof just for those times I don't want to put the ground panels out (travel days, parking lot stays, etc.)

For the ground panels, ultimately I will make the cord detachable at both ends (now it's fixed in the mouse hold box, just like the stock shore power cord), and will likely make some sort of inlet that doesn't involve the mouse hole (will just store the loose cord in that compartment when not using it). And I'll add a switch accessible from outside at that inlet (it's not recommended to disconnect the panels when there is current running through - so for now I have to either do it at night, or put the panels face to face to eliminate current before connecting/disconnecting).

To me the main thing about solar power is that it's fairly weak to begin with, so I want to do everything I can to not "give any of it away" once I have it. In other words, eliminate any leaks in the "hose." Panels are much cheaper now, but you still have to carry them along somehow, so we can't just "kill them with volume (wattage)" on our smaller rigs. Therefore I keep voltage drop under 2% for the entire run (all legs of wire added together), and run a controller that I can set to precise voltages and has temperature compensation. Even the little Sunsaver can do all that easily. And there are many other good choices for controller as well.

As you can tell, I'm not a fan of the kit. I don't mind spending money on good equipment, but it seems like you could do better, specs-wise. If I were going to insist on no overhang, I would likely run the SLP-070 panels with a controller of my choice (vs. a kit). In my case, I just couldn't quite get over the relative inefficiency, and after looking at the panels up on my roof, decided that a few inches of overhang was okay because the function was so much better. One note is that if you put the inner brackets slightly inboard on the panels (vs. right on the ends where they typically go), you can save a couple of inches of overhang, and get the panels snugged up closer to the edge of the top tier.

And lastly, if you just want to try things out with minimal fuss (and/or you like to or have to park in the shade), you can pretty easily set up a pair of 100 watt ground panels as I did. I had basically one day to get it all ready for a trip to visit a friend in Wyoming where I would have no access to shorepower. It was easy to get things set up and gave me a great/easy way to see how 200 watts would work for me. As a result, my ideas of what I "needed" for the roof changed considerably, and even when I get my roof panels installed I will keep the ground setup, because it's so useful. (I don't have huge power needs, but I do run a compressor refrigerator 24/7, and do plenty of computer and associated devices charging).

As I'm sure you've noticed, there are many different setups, opinions, etc. when it comes to these things. The above are just my own thoughts and experiences.

I hope this wasn't just TL;DR

BG

[HoosierB]

I was hoping you would respond, Blu.
Thanks for your input!
Like I mentioned, just starting to look at this whole "solar upgrade/ Progressive Dynamics 55 amp retro-fit/ maybe eliminate LVD thing". Pretty daunting...
BTW: I saw the Renogy Eclipse panels and they appear to be a good product as well. The "Airstream kits" use Zamp panels which I thought were suppose to be good too (Monocrystalline).

I will need to contract this whole "electrical upgrade project" to an installer which is part of my search right now. It's surprising that even living in the "RV Capital of the World", solar installers for RVs are hard to find.

Like you, I will be running the compressor fridge (Vitrifrigo). We are mostly on road, and try to go from shore power to shore power. Should a 200 watt system be adequate for our needs?

[Skillet]

Are you on Facebook? This guy has a large following for installing solar on rv's. He travels around the country doing it. When I'm ready to add some, I'm seriously considering having him do it. He also has a webpage with solar products that are sold through Ebay. $1 a watt on panels made in the U.S.
https://www.facebook.com/brian.boone.12382

[Scott]

It's surprising that even living in the "RV Capital of the World", solar installers for RVs are hard to find.

Like you, I will be running the compressor fridge (Vitrifrigo). We are mostly on road, and try to go from shore power to shore power. Should a 200 watt system be adequate for our needs?

With the prices of current solar systems, I can't believe they're not more popular. I see solar systems on rigs while I'm boondocking, especially in the desert, but in the Midwest and Canada, it's surprisingly rare. I guess in the northern latitudes generators are the accepted norm. Depending on your bank and your consumption, if you go from pole to pole, I would think 200w would be more than ample.

As usual, BG's comments/suggestions are sound. I'll second his view on that kit; it's too expensive. In selecting solar panels, I was looking for units that were 1) modern/efficient, 2) dimensionally workable, and 3) popular/available. If these requirements were met, a bit of overhang from the second tier wasn't going to bother me. However I can certainly understand how it would be an aesthetic issue for some. Popularity usually results in lower price, and more importantly, popularity makes it easier to source replacements. If you can get an identical replacement panel, then installation is a breeze with regard to mounting and wires, and there are no issues with setup or system compatibility. Blue already mentioned the replacement factor, but it's well worth restating since solar panels have a finite life. I rarely hear people discussing this. Panels gradually deteriorate, plus they're subject to damage especially when roof-mounted. Hail and tree branches come to mind for some odd reason. Some even get ripped off by erratic gusts. These are rare situations, but they happen.
I have a PWM controller which came in a run-of-the-mill kit (panels, controller, MC4 connectors). I added a temperature compensation probe for $10. The panels are wired parallel with a 13 foot long 8awg marine drop line going through the upper fridge vent into the coach then into the generator bay. There's a 15 amp in-line waterproof fuse just after the panel pairing. There's a 30 amp fuse between the controller and bank; this run is about 10 inches, and I think I used 10awg. My original plan was to use the PWM controller until I became acquainted with the system, then upgrade to something more efficient like an MPPT. But since it's installed and serves my needs just fine, I'm going to leave it until it fails. Achieving ultimate efficiency is a noble goal, but if I have what I need, then I don't lose sleep. I mounted my panels with the brackets on the panels' ends to get them as close to tier 2 as possible (slight gap to allow water and debris to pass through). I haven't measured the overhang, but to me it's trivial.

Edited to add a picture. This is out of focus since the picture was taken from a hilltop with my phone, then zoomed/cropped, but you probably get the idea.

[HoosierB]

Scott, excellent advice and much appreciated!
Your points on being able to "service/replace" deteriorated parts is why I would prefer a pro-install with some sort of guarantee as opposed to a self-built kit or a traveling installer
(all based on my limited abilities in this area).
Nothing is easy...

[Scott]

Hoosier... just to clarify, when I wrote "deteriorate" I just meant a gradual reduction in power production. It happens over the course of 5 or 10 or more years. It's a slow drop in efficiency. I hope it didn't sound like I was saying that they start to fall apart or anything like that. The glass/aluminum Renogy panels are quite stout structurally. Mine weigh 16 lbs each and are very easy to anchor sufficiently (just to mention another factor). But regardless, if you're contracting this work, a warranty on workmanship would be mandatory (I've seen some frightful installations). Good luck!

[HoosierB]

Scott, what "kit" did you use (Renogy) ? Size of panels (dimensions) in your pic? Any issues?
Thanks!

[Scott]

Correct, I have a Renogy monocrystalline kit. 21 x 47 inches each, if memory serves. No issues so far. I've used them quite a lot, in many different environments and conditions. They're tough.