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sailor323
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Joined: 11 Jun 2015
Location: S Central KY
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Posts: 281
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Topic: Solar on Roof Posted: 19 Jan 2016 at 3:00pm |
Originally posted by jato
Are you charging 2 deep cycle 6v or 1 or 2 marine 12v batteries? Also, how long do you estimate it will take to bring either of the above to full charge if you are say at 50% of full charge when you begin? I find this very interesting. Thanks.
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PV output depends entirely on ensolation. Under ideal conditions, the 2 panels should deliver about 23 amps. However, I would count on much less than ideal conditions. I guess I could count on about 15 amps. Over a 6 hour day, that would be about 90 amp hours, which represents a bit less than 50% SOC of the 2 6v golf cart batteries. I know from experience, running a refrigerator and a freezer, water pump, assorted lights and occasional appliances that 2 135 watt panels are sufficient to keep the 2 group 27 marine batteries (storage capacity about 200 amp hours, similar to 2 golf cart batteries) on my boat fully charged.
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M0tl3y
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Joined: 21 Sep 2014
Location: Utah
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Posts: 61
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Posted: 25 Jan 2016 at 12:07am |
Originally posted by snorris
Is there any way to mount panels on the roof? Yakama or Thule racks? |
I mounted fixed solar on my 178. See the attached install I put together.
It's not for everyone, I listed the various controversies with fixed solar panels. But it's up to the individual and their taste for portable panels, fixed, or none at all.
I'm sure that whatever you pick you'll make it work for you. Enjoy
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The 178 club
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funks
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Joined: 05 Nov 2014
Location: CALIF
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Posts: 98
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Posted: 25 Jan 2016 at 10:04am |
Nice Job Thank You for the Info
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TroutPod
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Joined: 23 Feb 2016
Location: Denver
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Posts: 2
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Posted: 24 Feb 2016 at 1:40pm |
sailor323 - Nice solar set up!
I have been on the fence about mounting panels on the roof of my 179 or just going with a portable system. My main hang up is that the portable system will allow me to get the panel in some direct sunlight pretty much wherever I camp. I don't want to feel like I have to position or camp in a certain spot to get roof mounted panels in decent sunlight.
If I went with a mounted system I would be looking at 300-360 watts on the roof, and probably doing the 24 volt wiring to the charge controller to help with voltage drop.
If I went with a portable set up I would probably be limited to 80-140 watts due to storage and transportation alone.
Can you tell me how your system handles in shady spots? Also, are your panels wired for 12 volt or 24 volt output to the charge controller?
Also, maybe it is a wash with 80-140 watts (portable) in direct sunlight versus 300-360 watts (mounted) in partial shade sometimes? What are your thoughts?
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M0tl3y
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Joined: 21 Sep 2014
Location: Utah
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Posted: 24 Feb 2016 at 3:08pm |
My opinion, with my fixed solar install, is that I'll still park in the best spot (shady or not) for my trailer and I'll deal with the lower sunlight levels. I believe it evens out, or is even better, in the long run to stick with fixed. My reasons are:
- Since I never put the panels away, they're always keeping the batteries charging, even if it's not optimal sunshine. I also don't have to hook up to shore power when I get home, or once-a-month in the off-season, to keep the batteries charged. - I've talked with people that use portable and they get nervous about theft, so unless they're in camp, they usually hide them. I am usually doing something away from camp (hiking, site seeing, whatever) by 10AM until late afternoon (optimal sunshine time). It doesn't make sense to put them away during this time but, as people note, if you leave them out, you risk theft. I don't want to have to worry about it. - To your point, most portable solar is in the 100W range because of size/weight convenience. With fixed solar you can easily have 200W, up to about 400W, on a R-pod roof, which compensates for indirect sunshine. - My number one reason:I'm generally lazy overall. I just don't want to bother/worry about optimal sunshine and I want to come/go without the hassle when I camp. When I'm home, I don't have to plug in just to "top off the batteries". After I did my install, the charger/panels take care of the batteries for me.
A lot of this really depends on personal preference. Some people really like optimizing the sun hitting their panels, and for them, fixed solar would drive them nuts. For me, it drives me nuts to have something else to drag around camp, or worry about theft. To each his own.
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The 178 club
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TroutPod
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Joined: 23 Feb 2016
Location: Denver
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Posted: 24 Feb 2016 at 3:21pm |
Those are good points, and I had forgotten about some of the stuff I've read about people worrying about theft - since I'm not in that position (yet) it hasn't really been a consideration.
How would you say your set up works when you are parked in a shady spot? Is it still charging sufficiently?
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sailor323
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Joined: 11 Jun 2015
Location: S Central KY
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Posted: 24 Feb 2016 at 6:28pm |
My set up is for 2 140 watt panels. Beware that larger panels cannot be shipped UPS and must be shipped truck freight $$$$$$. There is a good video about the effect of shade on voltage and current at this site https://www.altestore.com/store/solar-panels-c541/ Shading dramatically affects the current output of the panel while minimally affecting the voltage output. While a shaded panel might produce sufficient amps to keep a well charged battery topped up, it will not charge a discharged battery. Also, keep in mind that panels are made of multiple solar cells and the way those cells are wired has an impact on susceptibility to shading. BTW, the folks at altE are very good to deal with. I've bought several panels from them along with associated equipment. They have a 100 watt panel for $189. 2 of them could be hinged together to make a suitcase thing that compares favorably to thee Zamp 200 watt set up. Of course, you do have to add in the cost of a controller and wiring
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JandL
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Joined: 29 Mar 2014
Location: California
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Posts: 364
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Posted: 24 Feb 2016 at 9:51pm |
I posted pictures on my removable roof mounted solar panel. I have only one panel but there is enough room to get 2 up there. Podmods, Maintenance, Tips and Tricks - List Your Mods - Posted: 02 Aug 2015 (Page 39)
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JandL
2013 Honda Ridgeline
2012 177
2 Paynes in a Pod
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sailor323
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Joined: 11 Jun 2015
Location: S Central KY
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Posts: 281
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Posted: 25 Feb 2016 at 11:08am |
JandL, very nice idea for a non permanent installation
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M0tl3y
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Joined: 21 Sep 2014
Location: Utah
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Posted: 25 Feb 2016 at 5:39pm |
Originally posted by TroutPod
How would you say your set up works when you are parked in a shady spot? Is it still charging sufficiently? |
I agree with Sailor123 that shading has quite an effect on the panel output.
To add to the debate, you also need to consider the controller, length of wiring, and gauge of wiring. The PWM controller on most installations is, at best, 90% efficient. If using portable solar you're guaranteed to have a 30' minimum (if using the builtin connection), and as much as 50' of small-ish gauge wire. So plan on 200W of portable panel being effectively 160-ish Watts, at the battery, of value.
With a fixed install you can install quite heavy gauge or 10'-15' length and use an MPPT controller and get about 96% efficiency at the battery, or ~192W out of 200W panels.
As you can see, solar is finicky, and there's a lot of factors against getting the published rating of any given setup. My personal mantra, going into solar, was to be happy with half. I installed 200W because 100W is good enough to keep me happy.
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The 178 club
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