Boondocking in Grand Tour

[Boxster1971]

Originally Posted by Eberheld

Mike, I have a 2016 Interstate Grand Tour Ext and want to do what you did. How did you find roof space for your four panels? Did you remove the TV antenna? Did you purchase the extra OEM battery tray from Airstream? What batteries did you purchase? My wife and I want to do mostly boondocking. Have you any experience with portable solar? Thank you for any help you can offer.

I had to flip the MaxxAir fan and relocated the TV antenna to the top of AC unit. I'm attaching a picture of my roof top with four 100 watt panels.

My 2013 Interstate had the batteries mounted inside under the lounge seat. Your 2016 has two battery trays under the van behind the LH rear wheels. I believe they are Lifeline 12V GPL-24T that Airstream has been using for years.

I had to build my own custom battery trays to mount four 6V Lifeline GPL-4CT, two on each side behind the rear wheels under the van. That gives me a total battery capacity of 440 AH. I also upgraded the inverter/charger with a Magnum 2000 watt unit that allows me to run the microwave off the inverter. That also required modifying the 120V AC wiring to add a sub panel for things powered by the inverter. I'm attaching photos of right and left side batteries installed. Also a photo of right side battery rack before it was painted and installed.

Edit: Just noticed the battery tray photo of left side is upside down.

- - Mike

[M and R]

Boxster 1971, your picture of the panels appears to have a rail


Mike

[M and R]

The panels appear to be rail mounted. Were the rails on when you purchased, or did you install? If you installed, what brand, how difficult?


Mike

[Mcrid]

If you do not want to mess with a rigid mount approach you can take a look at my variant (post) to Boxter's roof. The '16 has the benefit of not having the antenna in the way

Also, you can buy the undermount battery cases from AIrstream if you are going to stay with the 24Ts. If you go 6volt you'll need to take an approach more like Boxter

[Boxster1971]

Originally Posted by M and R

The panels appear to be rail mounted. Were the rails on when you purchased, or did you install? If you installed, what brand, how difficult?

Mike

Yes my Interstate came with Mercedes factory roof rails. I think Airstream dropped them from newer models, probably to save some cost. I used Rhino-Rack cross bars attached to the roof rails. I did it to raise the panels above the bath vent. I also replaced the gray tank vent with a lower profile version to the 360 Siphon vent cap.

But there are other ways to mount the solar panels on the roof. I'd use the AM Solar mounting accessories if I was doing this again. See link below for details:
http://amsolar.com/rv-solar-panel-ki...g-accessories/

[M and R]

Quote:

Yes my Interstate came with Mercedes factory roof rails. I think Airstream dropped them from newer models, probably to save some cost. I used Rhino-Rack cross bars attached to the roof rails. I did it to raise the panels above the bath vent. I also replaced the gray tank vent with a lower profile version to the 360 Siphon vent cap.



But there are other ways to mount the solar panels on the roof. I'd use the AM Solar mounting accessories if I was doing this again. See link below for details:

http://amsolar.com/rv-solar-panel-ki...ng-accessories

Thanks for the link. I am going to add panels. Looking at different methods to best utilize the limited real estate.

[Mcrid]

Finally got around to installing the Victron Controller and reorienting the Solar Panels to series connected. I immediately noticed improved charging behavior especially late in the day in complete shade. Updated the document capturing the finished product.

[FlyFishinRVr]

Originally Posted by Mcrider

Finally got around to installing the Victron Controller and reorienting the Solar Panels to series connected. I immediately noticed improved charging behavior especially late in the day in complete shade. Updated the document capturing the finished product.

Good stuff Mc, thanks very much for taking the time to put this together.

May I ask for a little more detail on what you mean by "improved charging behavior"? It seems to me that by switching all to series, you are reducing your max Ah by over 60%. Are you really getting that much more later in the day to make up for the loss? If so, when I make the same mod, I'll follow your lead and go series vs. taking the parallel approach like I had planned.

[Eberheld]

How many watts of solar do you have on your roof? How long can you Boondock without recharging?

[Mcrid]

Originally Posted by FlyFishinRVr

May I ask for a little more detail on what you mean by "improved charging behavior"?

The MPPT controller will adjust its input voltage to harvest the maximum power from the solar array and then transform this power to supply the varying voltage requirement, of the battery plus load. Thus, it essentially decouples the array and battery voltages so that there can be, for example, a 12 volt battery on one side of the MPPT charge controller and a large number of cells wired in series to produce 36 volts on the other. The MPPT controller will harvest more power from the solar array. The performance advantage is substantial (10% to 40%). So even in low light, the panel array voltage will be above 12 volts and contributing some charge to batteries.

[FlyFishinRVr]

Originally Posted by Mcrider

The performance advantage is substantial (10% to 40%). So even in low light, the panel array voltage will be above 12 volts and contributing some charge to batteries.

Thanks!

I think I may go with 4 panels (assuming they fit!), 2 parallel groups of 2 panels in series. This would give me roughly 36v (full sun) and about 11Ah. The 11Ah should continue well past when a single panel's voltage would drop too much to power the controller, so maybe this will be the best of both worlds.

[Njg]

On this topic, I was thinking about wiring my two new renogy panels in parallel and then wiring that in series with the existing gopower 100w panel. Trying to get the best of both worlds. Any possible issues with this? Also, I was thinking about putting the victron in the space below the drivers side cup holder between the jump seat and the lounge... any problems with butt splicing wires to make the run from the Atkinson current location to there?

[Mcrid]

Originally Posted by Njg

Any possible issues with this? . . .

.

Yes there are issues with mismatching panels. Read here https://itechworld.com.au/blogs/lear...e-solar-panels

[Njg]

Originally Posted by Mcrider

.



Yes there are issues with mismatching panels. Read here https://itechworld.com.au/blogs/lear...e-solar-panels

Agreed. My concept involves 2 100w panels in parallel and subsequently wiring those in series with a third 100w panel. This trying to double dip the voltage benefits of series and the shading and amp benefits of parallel.

[FlyFishinRVr]

Originally Posted by Njg

Agreed. My concept involves 2 100w panels in parallel and subsequently wiring those in series with a third 100w panel. This trying to double dip the voltage benefits of series and the shading and amp benefits of parallel.

Maybe Lew will chime in, but I don't see why that wouldn't work. You'll double your OC voltage with the series connection so it should keep your controller "on" longer, and you'll also double your current vs. just having all 3 in series (so maybe 10-11A).

I assume you're looking to go with 3 total because of the roof space for flex panels? I was just up on my roof this weekend mucking around with antennae placement for my new WeBoost Drive 4G-X and it looks like the only way I can fit 4 total panels on mine is if I move the XM Radio antennae. If I do that, then I can put one more panel up towards the front of the rig and 2 behind the AC unit.

One thing to note is AS used Dicor and screws to put my solar panel on the roof. When I get around to adding more, I'll be using SikaFlex and tape. As Lew says, NO HOLES! Oh, and the techs did a sh*t job of putting Dicor around my Fantastic fan, so next time I'm up there I'll do a proper job of getting those bolt heads sealed. It made it through a VERY rainy winter with no issues (wettest on record!), but I'd rather have the job done right vs. hoping there isn't a problem later.

[Njg]

Three panels because my 2 new ones fit behind the AC and utilizing the third that was OEM from Airstream. I with they hadn't laid it crosswise on the roof because 2 panels could have fit in that space.

[toskeysam]

Here's the arrangement Lew was able to put on top of my 2013 AI Lounge Ext. The WeBoost antenna is beside the AC and a new TV antenna moved forward to beside the vent.

[FlyFishinRVr]

Originally Posted by toskeysam

Here's the arrangement Lew was able to put on top of my 2013 AI Lounge Ext. The WeBoost antenna is beside the AC and a new TV antenna moved forward to beside the vent.

How did he get the WeBoost into the van? Did he make a new hole or use an existing one?

[toskeysam]

Won't have access to the van for a week....will go up and look then.

[FlyFishinRVr]

Originally Posted by toskeysam

Won't have access to the van for a week....will go up and look then.

No worries. I'm guessing he re-used an existing hole (maybe for the solar) and just re-sealed it vs. punching a new hole through the roof, but I thought I'd check in case he got "clever" and found another way.