Two Options For Installing (2) 100w Solar Panels for my TM

[live4fun]

I have a 2020-2720 QS and have installed 2- 100ah of Lithium (LiPo) Batteries with Victron Monitor. I tested the battery install this year and everything is working perfect. We can easily rustic camp for 3-5 days on our loads with a 3 hr generator charge. Now, it's time to install the solar charge controller and panels. I have two good options on where to install (2 or 3) 100W Renogy panels.

1. Like most folks I had thought that on the rear roof above the battery compartment was best. PROs- Panels charge LiPo while driving. 16ft+ wire length to charge controller under sink. Easy place to install with space for 2 maybe 3 panels? Panels are invisible to most activities. CONs- Screwing or rivets, and glue through roof is always problematic. Clumsy looking wiring covers fastened to shell and arms of TM. I live on East Coast and travel a lot north and south, where >85% of the campgrounds are in shade when the TM is disconnected (no solar). Would require a portable solar for longer stays or more generator time. Adds an extra 50# of the weight of opening the roof.

2. I'm buying a new Honda Ridgeline TV with a Leer Cap and Thule rack above. My newest solar idea is to fabricate an aluminum frame for the solar panels which will mount atop the TV in the Thule rack in the rear. This frame will have locks and quick disconnect fasteners for easy lock in and removal.

PROs- Panels charge LiPo while driving. Solar rack is demountable from Thule and used as portable solar at campsite near TM (or left on TV). Additional solar power source stays with TV if power is need elsewhere. Can move panels to areas of campsite with sun and tilt them. No exposed wires on shell and all is underneath (easy wire install). No screws through roof. During at home parking, I have a cover for my TM where roof panels would be covered. Portable panel stays outside cover for constant charge on LiPo (and eliminates house extension cord plus TM 30a cord exposed on lawn). The charge controller can more easily be mounted in the front of the TM space and extended to batteries. Solar frame can be tilted if needed on roof or ground especially in winter season camping. Allows for easy expansion of a 3rd Renogy 100W panel (if controller is sized correctly). If I take my TV to the beach or a tailgate party, I would have AC power at my truck.

CONs- 24ft wire run from TM batteries to TV. Lose rack storage on Thule. Have to secure the wire leads well over the hitch to roof rack area.

Can anyone tell me that mounting the panels on the TM is a better idea than on the Thule rack on the TV? Did I miss something?? Other than the wire length, (which I could offset by using a thicker wire) the TV mounted solar panels appears to be a far better situation for someone living in shadier parts of the world and boondocking more. Any ideas on this mounting solution which is vastly different than most installs I have read on the forum would be very valuable to me. Please advise. I am grateful for all the constructive advice that you have. And I am very appreciative of all the great advice which is given about TMs here. thanks

[Bill]

You might get some ideas from this post.

https://www.trailmanorowners.com/forum/showthread.php?t=18799

Bill

[ShrimpBurrito]

I mounted three 100-watt Renogy Eclipse panels to the rear shell of my 2720SL (now called a QS), wired in series. Note that I bought both the Eclipse and "regular" Renogy panels to compare their performance, and the Eclipse panels, with the well regarded SunPower cells, outperformed by about 20% (max output 110W vs 90W, so I get 330W in direct sun). They're more expensive though, so that is a consideration. Coupled with 200 Ah of lithium batteries, we can camp indefinitely without regards to power consumption, even in the winter as long as I keep the snow off the panels. Also, there is enough sun that goes through my ADCO cover to provide more than enough power to keep the batteries charged. I used 3M VHB tape to attach the panels, so no holes in the roof.

I considered a portable setup, but I did not want the hassle of moving it around, setting it up and taking it down, having wires running all around the camper (trip hazard) or worrying about theft. With this setup, I don't even have to think about it.

Dave

[Wavery]

Here is our set-up on the rear shell. Z-brackets attached to roof with 3M VHB double sided tape (6x stronger than screws).

no exposed wiring.

Friends don't let friends buy Renogy.

I have 2x 100W solar panels (wired in series) mounted and 2x100W solar panels (in series) on 20' of 10G cable and wired in parallel to the other 2 panels.

As far as mounting the solar controller..... You want ti as close to the batteries as possible. I mounted mine on the lower back, outside the rear storage compartment door. It's protected at all times and stays much cooler.

Conduit for wiring.
https://www.amazon.com/gp/product/B07GPFDL1K/ref=ox_sc_saved_title_3?smid=A3MCRJA05CNKN2&psc=1

[live4fun]

I appreciate the dialogue and seeing the nice installations you’d done. Both of you guys are living in sunny CA with a lot fewer 80ft Oak, eastern pine, hemlock, and leafy trees around you at all the time. My acre lot alone only has a 1/5 of it in full sun a day and that’s not where my vehicles and TM are parked. Our southeastern campgrounds are no different mostly being close to water and a big beautiful over-story of trees. I am wondering if you were faced with not consistently having full sun morning to evening, you would have chosen the same fixed, rooftop location. I agree with you that its a hassle to move panels around, but its also not fun hauling out the 45# generator (and carrying throughout your trip) when the panels haven’t charged the batteries sufficiently when you thought they would).
I am glad to hear about the screwless application, and I haven’t totally written off having the panels located on the rear shell either, but once I fix them up there, I’m wondering how much sun I will receive when I’m off the road and into the shade? Even when I’m beaching camping in FL, the campsite vegetation can be thick or you swelter in the sun and high humidity. I thank you for your candidness and the discussion. Kurt

[ShrimpBurrito]

Hi Kurt,

While I live in SoCal, I am a shade seeker myself. We also mostly camp in this TM in the winter, where daylight hours are less. But, I just installed the panels earlier this year, and so have been out only a few times with them. At home though, I can readily test cloud performance. Yesterday we got epic rain here, and at least when I checked in between showers, when it was still very densely cloudy, I was still getting 20-30 watts. While that's approaching only ~10% of peak performance, it's still 2-3 amps, so even if it were like that all day, and only 8 hours of sunlight, that's still 16-24 Ah. I have no idea what your power consumption is, but that is not an insignificant amount of power, and that might be at or near worst-case performance. My peak performance is 330 watts.

That's another reason for more panels. Not because you need 300 watts, but because you need 30 watts (with a 300 watt array) instead of 20 (with a 200 watt array) when it's raining (or shaded).

Also worth considering is whether you wire the panels in series or parallel. If you wire them in parallel, the array voltage will not exceed the open circuit voltage of any one panel (probably around 20 volts). You need ~14 volts to charge a battery, so if it's cloudy you have very little buffer before the array voltage falls below the minimum voltage to charge. You'll also need thicker wire because the current to the solar controller will be higher.

If you wire in series, however, the array voltage is the sum of open circuit voltages of each panel (so, 3 panels @ 20 volts each = 60 volts). In this scenario, you can still be charging the battery when it's very cloudy, or the sun is coming in at a sharp angle (sunrise and sunset), because the voltage would have to fall far more to get below 14-volt charging voltage. Another advantage is that the wire from the panels from the array to the controller can be thinner, which is especially handy in making that bend from the roof down to the wall. The disadvantage with wiring in series is that if one of the panels is blocked entirely, the output of the entire array can be significantly degraded. There are "bypass diodes" built into each panel that bypass sections of the panel in case this happens to mitigate this effect, such that the panel can still produce output. For that reason, as I understand it, the more bypass diodes the better.

One approach you might consider is putting panels on the roof and trying it out. You know that alleviates the setup/tear down hassle, and it might be all you need. You could even do a test run, and simply lay the panels on the roof during a camping trip to do a sample test. But, if you find you need more, which may only be on certain trips, you can always add-on a portable or TV setup later. But with such remote setups, really think about how far you'd have to put the panels away from your TV so that the panels are in sun and the TM isn't. It doesn't take much to get to 30, 40, 50 feet, and your cable size is going to have to rapidly increase with such long runs.

We're going out this weekend and expect to be in shade (and freezing temps). I can report more details when we get back.

Also, note that HQST panels are made by Renogy. I think they're identical, actually, and quite a bit cheaper.

Dave

[rickst29]

The current is the current of only one panel, while the voltage increases with more panels (I have 4 panels, at more than 80 volts).

With only about 6A running through the long solar wires, even 12 AWG will have very little power loss. So, you can run from the front shell (down a lift arm, NO PIERCINGS!) and then clamp your solar wires to the underside of the TM, entering the battery compartment (where the MPPT controller is) from underneath. An actual entry box might be more waterproof than running just the cables and smearing them with 3M boat sealant.

2 panels is hardly worth the trouble, you should get at least a third.

[Wavery]

I have 4, 100W solar panels on my 2720SL.

I have 2, 100W panels on the rear shell (wired in series) and 2, 100W panels on the front shell (wired in series). I ran some 10G MC4 cable from the front shell to the rear shell panels and attached them in parallel. This gives me about 11A @ 35V to my MPPT charge controller (in full Sun) and the charge controller converts that to about 20A @ 19V to my 230AH LiFeP04 battery.

The solar wires from the front to back fold under the front shell, on top of the rear shell, when the trailer is folded down. The solar panels are mounted to the roof with 3M VHB tape. No holes in the roof.
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I only have to run our generator if I want to run the A/C or if it is a cloudy day. Otherwise, we are totally self-sufficient. We even have a 110V, 4,5cu ft dorm fridge instead of propane fridge.

We put our charge controller on the back of the lower shell, under the bed slide out, where it is protected from the weather and very close to the batteries.

[Padgett]

I put two on the back of my 2720SL. Was room for three but did not need. Was enough to keep two GC2 6v batteries charged and to make coffee in morning.

[jefflapoint]

I installed 2 100W Renogy black division flexible solar panels on the back shell of my TM 2922 and just secured them to the surface with EternaBond RoofSeal Tape. I've done this now on 2 RV's without issue. No screws, no worries about leaks, and solidly adhered.

[ShrimpBurrito]

Kurt,

I thought I'd follow-up with an experience we had camping a few weekends ago. We backed into a site that sounds similar to the ones you typically encounter: full shade at the back, sun in the front. In our case though, the only full sun was where we had the TV parked, and in fact, there was really no sun on any of the TV.

It was also in the winter of course, and so the sun was low on the horizon. Ultimately, we had virtually no power generation from our panels on the rear shell, but having them on the front wouldn't have helped either. We would have gotten a little sun if they were mounted on the TV, but the real spot was to the side of the TV, where we couldn't have parked but still within our site, and which was about 20 feet from the TM batteries. So in this instance, portable panels would have helped. We had more than enough power for 2-night stay, so it wasn't an issue, but it would have been if we stayed for a few days more.

Dave

[Kmikesell]

Jeff... Did your installation require the panels to go under the front shell when closed> If so were you not afraid of seal issues or scratching the panels?

[live4fun]

Okay, I’m ready to purchase my equipment for this TM solar install. I appreciate all the dialogue and I’ve incorporated most of it into my decision. I’ll put my solar equipment list below, and still have a couple undecided components. This reply is a request to give me some advice on the actual equipment that folks have installed. Thanks for helping for helping me out again. Kurt

1. Three ~22”x40” monocrystalline or flexible 100w panels- I heard folks say Renogy mono & flex, Windynation flex and HQST. I’m edging towards the flex panels since at least 1/2 of you have had good luck with them and ease of mounting, but the framed panels are okay too.

2. 12AWG wire in conduit from panels to controller in wiremold conduit down the lift arm. Use wiring provided by Controller to battery. I’ll mount this controller probably on the outside for heat dissipation and reducing clutter inside the compartment like Wavery. Do I need a fuse somewhere here?

3. 30A (40A?) 150v Solar Charge controller with Bluetooth. Victron ?, Renogy Rover?, Epever (not sure if they have BT).

4. Anything else I’m missing in this parts list.

[Wavery]

Okay, I’m ready to purchase my equipment for this TM solar install. I appreciate all the dialogue and I’ve incorporated most of it into my decision. I’ll put my solar equipment list below, and still have a couple undecided components. This reply is a request to give me some advice on the actual equipment that folks have installed. Thanks for helping for helping me out again. Kurt

1. Three ~22”x40” monocrystalline or flexible 100w panels- I heard folks say Renogy mono & flex, Windynation flex and HQST. I’m edging towards the flex panels since at least 1/2 of you have had good luck with them and ease of mounting, but the framed panels are okay too.

2. 12AWG wire in conduit from panels to controller in wiremold conduit down the lift arm. Use wiring provided by Controller to battery. I’ll mount this controller probably on the outside for heat dissipation and reducing clutter inside the compartment like Wavery. Do I need a fuse somewhere here?

3. 30A (40A?) 150v Solar Charge controller with Bluetooth. Victron ?, Renogy Rover?, Epever (not sure if they have BT).

4. Anything else I’m missing in this parts list.Running 3 panels can sometimes be an issue. You will need to run them in series in order to have adequate voltage for your MPPT charge controller to work. Lets assume that the open circuit voltage on each panel is 22V x 3= 66V. Be sure that your charge controller can handle whatever your open circuit voltage is x 3 + 10% for good measure.

Flex panels typically have a much shorter life span than any glass panels. Although the initial install may be easier (which has not been my experience) but you will have to remove and replace them more often. The initial cost is higher as well.

I personally recommend an even number of panels so that you have the ability to run pairs in series and wire the pairs in parallel.

On small systems (under 600W) it's not really necessary to fuse between the panels and controller unless the panels don't have their own fuses. Even then, the heat generated from a short would likely not be dangerous, just melted, stinky wires. Having said that, I put 30A inline fuse between my panels and my controller and 30A DC circuit breakers between my controller and my positive and negative busbars. That's because I am using a 230AH LiFeP04 battery.

[ShrimpBurrito]

I put 30A inline fuse between my panels and my controller and 30A DC circuit breakers between my controller and my positive and negative busbars. That's because I am using a 230AH LiFeP04 battery.

Take note of the voltage ratings on fuses when putting them inline between the solar panels and controller. The rating for many fuses is 36 or 48 volts, since a higher voltage could cause arcing that would defeat a blown fuse. There are inline fuses with higher voltage ratings, you just have to seek them out.

Dave