Any reason I should "not" install the physically largest panels on the roof of our travel trailer?

I have room to mount five of these Adani panels: Adani 650w bifacial

They seem like a good option vs the smaller/lighter panels with less output. I would not be able to place more panels (of any I've seen available) to equal the output of the five Adanis.

The free shipping makes it tempting.

Thanks
Chris

I see two issues…

(What battery voltage are you using?)

First five panels will need to be either 5p or 5s or two Solar charge controllers. With of VOC of 49.12 you will need about 300v of solar input if you are doing 5s - unless you are doing an AIO. Or two SCC - a 150v one for four panels in 2s2p and a single one on another SCC.

Second- that’s a lot of glass bouncing up and down as you hit all the potholes in our roads. It will probably be fine, but….

I would design the trailer mounts to support the whole frame. That way your trailer mounts don’t add any extra stress to the solar panel frame.

I went with 200w panels on my RV - cost much more.

Good Luck!

They also show a minimum order quantity of 10.

Funny i made a thread with a similar title. Asking if there is any reason to "not" buy bifacial panels for an RV.
Majority of responses was its not a good match. Im down in the hot desert though. Heat seemed to be one of the issues.
Are you planning to tilt the panels so the bottom side will see some light? Seems like youre doing a solid flat mount.

Rocketman said:

Second- that’s a lot of glass bouncing up and down as you hit all the potholes in our roads. It will probably be fine, but….

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I'd worry about this. If you look at all the warranties for panel manufacturers they usually exclude covering any warranty if mounted on something mobile. Logically smaller panels would make more sense since you wouldn't be out much if you lose one. I'd also be surprised if those panels are as structurally sound as the smaller ones. You'd have to look at the installation details to verify.

rhino said:

I'd worry about this. If you look at all the warranties for panel manufacturers they usually exclude covering any warranty if mounted on something mobile. Logically smaller panels would make more sense since you wouldn't be out much if you lose one. I'd also be surprised if those panels are as structurally sound as the smaller ones. You'd have to look at the installation details to verify.

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Interesting - I have 4 x 300w panels mounted flat on regular PV rails on top of my 7 x 14 cargo trailer -> camper. After 3 years, have gone down a few 'pretty rough' roads - gaps in pavement making huge bumps and wash-board gravel roads at 30mph (shake you're false teeth loose) and haven't had any trouble so far.

I have put 9,000+ miles, including a trip from NY to UT and back on my RV with 4x 415w (80"x40") panels and no issues so far. I did mount them with 8x z-brackets each. I could have fit a fifth but left it off so I would still have reasonable access for maintenance.

What voltage are you going to use for your battery bank?

If you ran a 24v battery bank I thought you might be able to use a Victron SmartSolar MPPT 150/100 with all five in parallel. Your Isc is 13.63amps so 13.63x5=68.15amps just under the 70amp max. That was until I looked at the detailed panel spec and the Isc of the 535w panel can increase a good bit with the bifacial gain but in a RV mount that should be low... Bifacials have an unknown gain that makes your V and I specs a little squishy.

You could run four panels in 2s2p on a 150/70. You could run two controllers and put 3 in parallel on a 150/60 and 2 on a 150/35 (or a 100/50 in parallel only). The fifth panel is going to drive up your overall $/watt vs just using four but that is mostly a budget decision.

If you want to run a 12v battery bank and not be clipping a lot of power you will need to spend a good bit more on larger mppt controllers then the above examples.








I am using four 415w panels in parallel to a 150/100 controller with at 12v battery bank. More info on my setup here

I have an EG4 EHV3000-48 and an EG4 -LL-S 48V battery on order. My roof layout allows for four (higher output, ~400 and up) panels easily, and five with some reconfiguring/removal (hdtv and radio antenna). I could fit 10 to 12 ~200 watt panels, which would be increase the complexity of everything. It seems maximizing panel size/output and having fewer panels that I could tilt is a better way to go. Buying ten isn't a problem since I have another project for any excess panels. Like carrying one or two on the back bumper for a ground array.

My main concern is robustness of the panels for travel-trailer life (being dragged around on rough roads).
So far, this seems to be a non issue as long as they are mounted well.

Chris

I had similar thoughts due to seeing the smaller panels on other installs. From my experience with my panels I would not worry about that with a good mounting solution. Less complexity, less holes in your roof, less wiring and connections, potentially less overall weight and cost per watt. I think part of the reason you dont see a ton of larger panels used on RV's relates to the type of RV folks are installing large solar arrays on. High-end and larger RVs generally have several air conditioners a bunch of powered roof vents and a few skylights and more. The roofs tend to be busy and require the flexibility of smaller panels to get the most out of the free space.

Take a look at the size of the panels that you are interested in - and cut out a similar size sheet of plywood.

Now take this and try to lift it up on top of your RV without risking damaging the vehicle, yourself or things around you.

This test only costs about $30 - 40 and will allow you to see exactly what is involved before committing to those large panels.

I build mobile electrical systems and put panels on top of vans and SUVs. Our default panel size is 26 x 59 inch and we sometimes go 1 - 2 inches larger - but not more. Try moving that big ply board around and you will understand why.

As far as mounting using z brackets - that really is not enough air flow under a panel and will result in heat coming into the vehicle from the roof vs the solar panel acting like a shade.

c473 said:

I have room to mount five of these Adani panels: Adani 650w bifacial

They seem like a good option vs the smaller/lighter panels with less output. I would not be able to place more panels (of any I've seen available) to equal the output of the five Adanis.

The free shipping makes it tempting.

Thanks
Chris

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As 400bird notes these ship as a pallet of 10, minimum, do you have plans for the other 5 already?

It’s also noted they don’t do residential delivery for these, only locations with a receiving dock, due to their size-so that may also be an issue.

HarryN said:

Now take this and try to lift it up on top of your RV without risking damaging the vehicle, yourself or things around you.

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This is a good point. I was fortunate to do my build in a pole barn with a loft that let me walk right out on my RVs roof. Placing the panels was still a two person operation. These panels are nearly the size and weight (60lb) of a full size sheet of 3/4" pine plywood.

I recently installed six 450W (82" x 41") on my 5th wheel. I used commercial roof racking (Tamarack) to mount them with 6 connection points per panel (3 rails). I could have gone with twelve 200W panels in the same area, but chose the larger ones because it reduced the roof penetrations and wiring, plus the Tamarack rails keep the panels 3" off the roof for better ventilation. Also I saved about $500 over the 200W panel price which paid for the racking. The 700 mile trip I took recently proved the concept was a good choice for my situation. The Tamarack rails & mounts are rated for 180 mph winds on a residential roof.

Good info in this thread!

I too went with large panels (62lbs each) for much the same reasons as everyone else. They were advertised for yacht marine use. I am hoping they will hold up when I finally get mine mounted.

Are people still moving about on wooden wagon wheels?
I keep seeing people mention rough roads and harsh rides. Just how stiff is your suspension?
No, a sprung vehicle is not a rough ride!
Springs on the suspension, air filled tires.... they do amazing things to smooth out the ride. Though your coffee drink might spill it still is not a rough ride. Stop with this. You will not break glass hitting a pot hole unless the item is poorly or improperly installed or misused or some user-error on his part, not the vehicles.

Big glass solar panels will be fine structurally on the roof, that is not at all the issue to discuss. The issue is asked if that many solar watts in one panel is a good choice or should he go with smaller panels with lesser watts each.

The cons to one or two big panels is that if one goes bad it is expensive to replace. They do go bad and not from driving around.
On mine I use multiple panels and split them into two sets of solar systems. One benefit is half the panels can be in the shade (basically useless) and the other half in the sun and I get 100% of the sunny panels available power at that tilt/etc.

I do not think there is any right answer. Many variable on your specific rig that might make sense for you and make nonsense for others, but do not think the sky is falling because a bumpy road. I have NEVER broken anything in my rig, any of my rigs, over 100,000 miles of driving all over the country, never. I have broken an axle, had blow outs, but anything above the springs has always been unharmed, never fallen down, never broken, nothing. Fine. No issues.

I put 6x 390w bifacials on my 24' trailer also. Fit perfect. No problems.


Now just know that any bifacial on a trailer isn't going to benefit from the bottom side. Those aren't 650w, they are 535w.

You don't need bifacial but if they are cheap, why not?

The panels will be fine unless hit by something which is no different than a busted window.

Just make sure your RV's roof trusses can hold the fasteners you'll be using to mount them.

Checkthisout said:

You don't need bifacial but if they are cheap, why not?

The panels will be fine unless hit by something which is no different than a busted window.

Just make sure your RV's roof trusses can hold the fasteners you'll be using to mount them.

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It's not about not needing them, just don't expect 650w out of them, because you won't get it. It's a 535w panel.

Lt.Dan said:

It's not about not needing them, just don't expect 650w out of them, because you won't get it. It's a

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Are the higher wattage panels the same physical size as "regular" panels?

I mean I guess I could look it up but,

Are they better at collecting energy in low light conditions?

Checkthisout said:

Are the higher wattage panels the same physical size as "regular" panels?

I mean I guess I could look it up but,

Are they better at collecting energy in low light conditions?

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The larger panels are typically going to have better watts per square foot, since you have less frame area etc.

There is also less weight because of reduced framing materials, less wiring, etc.

Collecting energy in low light would be dependent on the panel manufacture and quality, not size.