One or two panels

Alan57

Which is better, one single 200 watt flexible solar panel or two 100 watt solar panels? 

AnOldUR

There is no "better". In the right conditions, 200 watts is 200 watts. The only consideration is that with two 100W panels you have the option to wire them in series or parallel. Series allows for smaller gauge wire and less voltage drop due to lower current. Parallel is better for partial shade since the panel will operate independently. With series a MPPT controller is the best choice because it is more efficient at higher voltages, but is more expensive. With parallel, either MPPT or PWM controllers will be fine. Although my choice would be a Victron MPPT because it has networking advantages.

edit to add, that since you said flexible, I'm guessing that you mean panels mounted to the roof?

Sharon_is_SAM

I prefer 2 100 watt panels.  More options, lighter to carry and may give you more options to store.  

elbolillo

If you are talking about external panels, then I would definitely say a single 200w panel. No need to complicate things.

Horigan

Given you're asking about flexible panels, I assume you're referring to panels mounted on your T@b roof.  In that case, it depends on how much you want to chase the sun.  If you're willing to always point a single 200W towards the sun, whether it's on the front or back, then that's the best option.  If you want to just park randomly relative to the sun, then two 100W is better, one in front and one behind the fan.  Then at least one will be better positioned towards the sun.

Having just done a trip with limited sun, I just replaced our two 100W panels with two 200W panels.  To me that's the best option.

Alan57

Flexible panels fixed to camper is correct. Mostly want to catch sun while driving. Plan on traveling 4 hours to 5 hours per day, park in business that allow, most likely in sun, and do a little sight seeing. Two 200 watt panels would be great, just not sure I have the space with tire rack on back and what looks like bath vent to one side of center exhaust. Also unsure how to determine size of controller, wires, fuses, etc. for two 200’s. I was going to purchase kit from Sun Powered Yachts as suggested from a previous post and they did not have that option. Just replaced battery with lithium 100ah. Next issue is where/how to run wires. I was thinking under the moulding.  

Horigan

Got it.  Which T@b do you have?  400 or 320.  That would determine the routing. 

I should have mentioned that the latitude you're in plays a factor.  I'm in the PNW, so we don't get a lot of sun right above us compared to southern latitudes.  Having a rack in the back is a factor as solar panels reduce output greatly with some shade.  It's not linear with surface area in the shade.  

With 200W total you can do a 75V 15A charger.  Two 200W you need 100V 30A.  (At least for Victron products.)  Just divide the total wattage by 12V to get the amperage.

Alan57

It is a 2017 320 and I am in Southern Indiana. Does anyone know if the flexible solar panels able to bend along the short side enough to contour to the curvature of my 320 just above the tire rack? I would be interested in knowing if anyone has successfully mounted two 200 watt panels with a tire rack and how that was accomplished. 

RTWCTS

I think the big thing is to measure your intended roof area mounting location and shop the wattage you want by panel size. Manufacturers make different sizes of the same wattage panel. Other specs vary too, but size seems to be your biggest issue if you're looking for 400W on the back. 
Here is a pic of two 100W panels on a 2018 T@B 320 in the location you're talking about.  You can see they overlap the Yakima tracks. To be most effective the racks were removed during use. They were enough to keep up with the 3-way fridge demand in 12V mode while driving with only a modest drain on battery.  I believe they were HQST brand (shipped from same warehouse as Renogy products). They were selected because they were the shortest length 100W panel that could be found at the time. The top area of the roof where these are mounted was almost a perfect angle.

FishDoctor

I put a 200W panel on my 2017 T@B 320s earlier this year, but I don't have a rack. The bottom edge of my solar panel (not counting the pieces of tape) in the picture is 43 inches from the line of trim between the rear handles if that helps you. I don't think that it would be possible to change the orientation and fit a 200W panel to each side of the roof vent (maybe there are longer/narrower flexible panels). 2 100W panels could be arranged that way. The panel could probably be mounted another couple of inches higher, but I wanted to avoid possible shading from the roof vent. The panel is a BougeRV Arch 200W Fiberglass Flexible Solar Panel and there was no problem getting it to follow the curve of the roof. This setup easily replenished the depletion from a day or two of camping (2 100AH LifePO4 batteries, but I'm not using an inverter for heavier battery draws) on a relatively sunny day while camping or driving down the road. The panel is connected to a Victron 100V/30A charge controller. That would allow me to integrate an additional panel on the front of the roof, but right now I don't think I need it.

AnOldUR

@Alan57
To avoid any interference with the Yakima roof rack on the back of your 320, you can put a 310W panel in front of the roof vent.

FishDoctor

Sweet!!

AnOldUR: in the small-world department, my brother teaches at Stockton University! What brand of solar panel is the 310W in your photo?

AnOldUR

@FishDoctor
The panel is a Sunflare XPLOR. It's the one the nuCamp uses on some 400's. I bought it from nuCamp through our local dealer, Miller Trailer Sales. Miller no longer sells nuCamp, but still does a great job at service. 

Stockton is actually not the location of Stockton University. It's a small river town about 20 miles north of Trenton.

FishDoctor

AnOldUR said:

@FishDoctor
The panel is a Sunflare XPLOR. It's the one the nuCamp uses on some 400's. I bought it from nuCamp through our local dealer, Miller Trailer Sales. Miller no longer sells nuCamp, but still does a great job at service. 

Stockton is actually not the location of Stockton University. It's a small river town about 20 miles north of Trenton.

Thanks!

Horigan

I could not find a 310W Sunflare XPLOR flex panel on line anywhere.  Just a 240W, but it's spendy compared to a 200W Renogy, which is what I recently went with.

Alan57

Thanks to all for the information and especially for the pictures. I would like to know how you ran the wires. The front 310w would be simplistic. I will find a dealer and check the price.  I was hoping to avoid drilling into the roof, only because I will be doing the install and am not confident in my ability. I was hoping the wires could go under the trim. If they won’t easily fit under the trim and I don’t drill into the roof, I guess wire loom is the obvious choice. I zoomed in in the pictures but cold not see any wires. Again, thanks!

FishDoctor

For my install, I ran the cables from the solar panel to the drivers side of the roof and then placed them under the trim to run them to the front of the trailer. The cables emerged from under the trim below the trim covering the front driver's-side handle. I then routed them to the back of the tongue box, where I have the batteries. The exposed wires in the picture were placed inside a piece of electrical loom and then covered with Eternabond Roof Seal Tape.

AnOldUR

@Alan57
Our 2020 320S came with a smaller panel on the front so wiring was in place. The junction box on the new panel was in a different location, so another hole in the roof was necessary, but there was enough slack in the wire to reach the new location. 

That said, the location of the junction box is behind the cabinet above the sink. I only had to cut through the outer aluminum skin to connect to the existing wiring, but it would not have been difficult to also go through the inner panel and route the wires hidden inside the cabinet and drop down behind the wall in the bath.

Here's a picture of where the original hole was located and the marked out location for the new one.

 

RTWCTS

Our wires were run in the same fashion as @FishDoctor, except down the passenger side (no advantage, just how my mind worked at the time).  The only other difference is I continued the wires all the way under the trailer, beneath the trim and then through a loom to the tub. On the side of the tub, I had installed a port where we could attach our two 100W briefcase panels. The rooftop and ground panels met at a busbar before going into the Victron MPPT controller. I had mounted the controller on a panel that I installed in the back of the tub. 
The panel themselves were attached using 3M's VHB tape on the top and sides. I left the bottom open so any potential moisture could drain out. The exposed cables on the roof were held in place with cable ties on cable tie mounts. To strengthen the bond of the mounts I used Eternabond patches with a small cutout to allow the cable tie to attach. 

elbolillo

The wires from the original panel on our '23 Tab 400 were run externally so I just did the same for the additional panel that I installed.

Having the additional 180w panel keeps us charged up while traveling.

Alan57

Decided I will run wires under the trim. How is this removed on a 2017 320? Any sealant or glue needed?

Has anyone mounted a Renogy 200W flexible panel horizontally, length running side to side? The product pictures show it flexing in length. I want to know it will flex enough in width to contour to the camper? If it did, I could put one either fore or aft of the roof vent fan and have the ability to expand to two.

tphaggerty

I have 2 175w panels on my 400. They flex both ways, length and width. 

Horigan

Here's my recent installation of Renogy 200W panels.