Need to make a Solar Panel decision.

[Sportzfann]

Very nice job. I’m guessing you are full time?

We live in Oregon and I recently retired! We have gone to quartzite last January for the first time to see the Big Show and do some boondocking. I added the panels while we were in AZ. I added the Victron inverter 3000 watt 2x120 and 400 AH lithium so we can boondock without hookups.
We camp as half timers ��. For now anyway…

 

[Lance Glogowsky]

Just to share a bit of my experience. I can't climb ladders anymore, so I tried measuring from inside the trailer. My calculation said I could fit six panels. The guy I bought the Victron stuff from said he could install the panels, and we agreed that he would order a pallet of 10 panels and sell me the six I needed. When came time to install them, though, he said he could only fit one or maybe two panels on the roof, so I loaded all six panels into the back of the truck (moving all of that stuff to the back seat and inside the trailer). Superstition Solar thought they could do better because he uses a different mounting bracket. He looked and measured some and decided that he could fit four panels on, so I sold two panels while I was at Quartzsite. When it came time to actually put the panels on, only three would fit. The fourth one lacked about two inches of fitting. Tomorrow it will be installed on the roof of our casita here at The Ranch, where it will power a small security system.

One of our neighbors has a Class C with the roof completely covered in solar panels. They are mounted on a raised rail system and go over everything else. Of course, he also replaced the rooftop air conditioner with a minisplit mounted on the rear bumper....

Measure carefully and be sure to include room for the brackets. Also, you have to leave some room around air conditioners.

Good advice. I feel pretty confident I’m good for six panels without a lot of room around them. But enough to maneuver around the roof. I’ll find out this coming week.

 

[SolarPoweredRV]

There are two main benefits to "Residential" Solar panels vs "RV" Solar panels.

Residential Solar panel efficiency increases every year and, generally speaking, the price goes down every year. Consequently, you will get more wattage for less money.

Because of the increased efficiency of Residential panels, you also get more wattage per square foot of roof space.

Like others have said, installing Solar panels on your RV roof is like a game of Tetris, you want to maximize the wattage you can fit on your roof with as few panels as possible while also minimizing your costs, both purchase costs and installation costs.

As an example: I installed four, 305 Watt, Canadian Solar, panels on my roof for a total of 1,220 Watts. By contrast, I would have needed six, 200 Watt Renogy panels or twelve, 100 Watt "RV " type panels. In my case, my roof layout allowed for the larger Residential panels. Additionally, my Canadian Solar panels were technically superior to the RV type panels because they can generate 11% more energy in lower irradiance conditions (think cloudy days) than conventional Solar panels. This is especially useful since RV Solar panels are not mounted at the best angle relative to the Sun.

I Just read that grid scale Solar panels are going for $0.10 per Watt.

20 years ago that number would have been believed to have been impossible!!!!! At the time, it was believed that a price of $1.00 per Watt was needed to get everybody to install Solar panels on their roof. This has proven to be relatively true... in Australia the installed price is close to $1.00 per Watt and 60% of Australian households do have Solar installed. Unfortunately, the price of installed Solar in the USA is closer to $3.00 per Watt and we have a much lower percentage of Solar households.

Fortunately for RVers, the price for an affordable Solar system is well within our reach (especially for everyone who has read the thread "Affordable Solar..." linked above in post #4 ).

 

[Butcher]

My opinion is real estate is the main factor for installation. The larger the panel, the harder it will be to find the real estate to put them in. Residential panels might be the cheapest per watt, but if you can't get them installed, then you got panels you purchased that you probably have to unload at a loss.

I know RV manufacturers have enough design issues but if I designed an RV, I would do my best to organize a roof that you could maximize space. I am certain a solar manufacturer would jump on the opportunity to work with you on that. The additional sales would pay for the time invested. If I was a solar manufacturer, I would try and partner with an RV manufacturer to work with them to get my panels to fit. Like someone mentioned above, 2 inches prevented the panel to be installed.

It's a matter of looking at specs, space, and coming up with different ideas. I did see one person build an additional level to install all the panels above all the obstacles on his room. Good idea, but not something I would want.

It would suck if you cannot climb a ladder and take a peek. Even worst for me is if I had to sublet the entire job to someone else.

 

[SolarPoweredRV]

My opinion is real estate is the main factor for installation. The larger the panel, the harder it will be to find the real estate to put them in. Residential panels might be the cheapest per watt, but if you can't get them installed, then you got panels you purchased that you probably have to unload at a loss.

I know RV manufacturers have enough design issues but if I designed an RV, I would do my best to organize a roof that you could maximize space. I am certain a solar manufacturer would jump on the opportunity to work with you on that. The additional sales would pay for the time invested. If I was a solar manufacturer, I would try and partner with an RV manufacturer to work with them to get my panels to fit. Like someone mentioned above, 2 inches prevented the panel to be installed.

It's a matter of looking at specs, space, and coming up with different ideas. I did see one person build an additional level to install all the panels above all the obstacles on his room. Good idea, but not something I would want.

It would suck if you cannot climb a ladder and take a peek. Even worst for me is if I had to sublet the entire job to someone else.

I agree, Real Estate is the main factor, however, I feel that maximizing the use of that Real Estate with Solar panels that are more efficient (i.e.: Residential panels) is the metric to strive for, coincidentally, Residential panels are also more cost effective because of that efficiency difference.

Some may have noticed that I am recommending Solar panels in the 325 Watt range. These panels will be slightly smaller than a 400 to 450 Watt panel that is most common for Residential panels today. Similarly, panels in the 250 to 300 Watt range would be smaller than the 325 Watt panels. The key is to measure your roof and find panels that will fit, while giving you the maximum Wattage. You might determine that you can get two panels of one size and two panels of a different size to fit, in this case, you could wire the two same size panels together and feed a Solar Charge Controller for each pair of panels.

While Solar panel sizes are somewhat standardized, if you look at panels of different Wattages, you should be able to fit enough panels on your roof to charge your battery bank.

Like I said earlier, it is simply a game of Tetris.

 

[50ST8R]

We took advantage and put six Renogy 175 watt panels up with 400Ah Battleborn batteries. I have 3 panels in Series and then parallel them together. Simply watch what your voltage will be when you consider your panel isolation switch as the maximum voltage I can deliver exceeds the 48 volts many DC cut off switches max out at. We also added tilt mounts which makes cleaning and inspecting the roof much easier.

 

[Oldcow]

Like batteries, is it a no no to mix similar wattage panels from different manufacturers? I currently have 2 200W Rich panels and would like to add another 4 to 8 panels. I have just started looking and it seems the Rich panels are not inexpensive and I don't see any deals out there for them.

Oldcow

 

[huntindog]

For the benefit of someone who knows nothing about solar applications, what is different about residential panels, and what are the other panel options available? I assume the residential panels costs less per watt?

Residential panels are larger because it makes sense.
A house has a lot more space for panels, and it needs much more power. It also doesn't move. so the panels can be placed in the best solar locations.
An RV has a much smaller roof, and has a lot of things on it that need to be worked around. Sufficent room needs to be left empty to allow room to do maintence.. Most RVs will be used in many different locations, so it is best (IMO) to have panels evenly located across the roof. That way it has the best chance of harvesting some solar at many locations.
IMO, the only advantage of Residential panels is a lower cost per watt.
For RV use, smaller panels make more sense in most cases.

 

[SolarPoweredRV]

Like batteries, is it a no no to mix similar wattage panels from different manufacturers? I currently have 2 200W Rich panels and would like to add another 4 to 8 panels. I have just started looking and it seems the Rich panels are not inexpensive and I don't see any deals out there for them.

Oldcow

Instead of mixing Solar panels, I would simply create another string for the new panels and use a second Solar Charge Controller.

I am a big fan of Residential Solar panels. They are usually higher wattage per sq foot and they are much lower in price per Watt. The only issue is their size, you simply need to measure very carefully to ensure they will fit on your roof. I recommend looking at panels in the 325 Watt range, they will have a smaller footprint than the 450 and higher panels.

As far as mounting them on your roof, I recommend making a cardboard template the size of your prospective panels (be sure to allow for your mounting hardware) and getting on your roof to figure out the placement. Chances are that you have enough open space to accommodate the larger Residential panels.

PS: be sure to consider transverse mounting for some of your panels to make them fit, that is what I wound up doing. I used four, 305 Watt, panels, I mounted two on the passenger side rear, one on the driver's side middle, and one, transversely right behind the front cap. This configuration allowed me ample space to access the roof for maintenance.