Solar, worth it in my case?

If you're worried about shading, get more smaller panels wired in parallel. If one is shaded, the rest will be producing power.

Regards,
Doug

C Schomer wrote:
I never used the luggage rack so I put a 120w poly panel on the rack and I used a mppt control. I also switched to LEDs. That one panel fully charged my two 6gc batteries by the end of every afternoon even if it wasn't parked at a good angle for the sun.

Yes. 120W or even 80W panel on a sunny day, even a flat panel, even in winter, will generate enough for LED lights, DC circuits of LP fridge, and small electronics like laptop or radio/TV/DVD. Basic necessities take very little energy.

But when you "have to" run a vacuum through some monstrous inverter, or a microwave because don't know how to re-heat the leftovers on stove top, or watch TV with satellite receiver for 5-6 hours, this is when things go downhill. All these things you can leave out and it wouldn't affect your health or physical comfort. But most people don't want to.

I can understand the "better safe than sorry" concept, especially with Cpap machine... But... There are 2 things to consider here.

1) It is very likely that generator is not needed in this scenario, i.e. the battery would still be +50% in the morning without that genny run. TV itself draws very little, a good energy efficient model will draw less than 10 AH in 4 hours. If yours is not efficient, it pays getting a better one. Satellite receiver and dish motor draw a bit more, though. Up to 30 AH more, in 4 hours. Your battery monitor can tell you the morning SOC.

2) Even if you need 30-40 AH from sunset to bed-time, and after checking with monitor you've estimated that without a generator this 40 AH would've brought you to below 50% in the morning, the generator run in the evening is very inefficient. It takes same amount of time, noise, fumes, and almost same amount of fuel, to put 40 AH into battery at +50% SOC as it would take take to put 80 (if it needed 80). Try running it same 1.5 hr in the morning. Or 0.5 hr in the evening and 1 hr in the morning.

Almot wrote:

Keith Haw wrote:
the 1 panel I have will charge my 4 gp24 batteries by 1-2pm on most days. If it wasn't for the need of a CPAP at night I could run without the generator. But I choose to run my genny about 1.5hrs before 10pm every night to make sure the batteries will last till dawn.

I wonder how much AH the generator can put into almost full battery in 1.5 hours. Unless there are substantial loads running between the sunset and 10pm - some heavy stuff that you didn't run during the day - the generator run doesn't look like necessary. Or you need one more panel.

After sundown is when we usually move indoors and watch TV for a few hours so heavier amp usage. I'm fairly sure we could make it all night without the genny but rather be safe than sorry. The genny running the PD9260 converter will usually bump the batteries up to full leaving them at 13v when I shut the generator off. But your right, I do need at least 1 more panel and would prefer 2 more. That along with swapping to gp27's or 4-6v would be even better.

This 5er already had it but I added solar to our previous unit. I never used the luggage rack so I put a 120w poly panel on the rack and I used a mppt control. I also switched to LEDs. That one panel fully charged my two 6gc batteries by the end of every afternoon even if it wasn't parked at a good angle for the sun. I got the stuff from AM Solar. Craig

Keith Haw wrote:
the 1 panel I have will charge my 4 gp24 batteries by 1-2pm on most days. If it wasn't for the need of a CPAP at night I could run without the generator. But I choose to run my genny about 1.5hrs before 10pm every night to make sure the batteries will last till dawn.

I wonder how much AH the generator can put into almost full battery in 1.5 hours. Unless there are substantial loads running between the sunset and 10pm - some heavy stuff that you didn't run during the day - the generator run doesn't look like necessary. Or you need one more panel.

sjturbo wrote:
Hope I am posting in the proper forum. DW and I tend to boondock or stay in parks with no electric. Although we have a generator I am reluctant to use it because of the smell and noise. I have a 2010 Laredo 316RL! I am considering solar but have some concerns based on my application. I have read much regarding the placement and pitch of the panels. Specifically that any shading by vents or other obstructions can reduce the panel output considerably or completely. And, With my physical limitations I am not able to venture up the ladder to "tilt" the panels. My concern is that the real estate of the roof of the 316RL is very broken up by various vents and the air conditioner. So my dilemma is since the panels will be laying flat and likely at any given time will be partially shaded by the various vents and obstructions, am I wasting time and money for little gain?

Money for gain, only you can answer that. Solar is only 1 part of a bigger setup to limit generator use. LED's, limited energy use and battery bank need to also be thought out.

As far as obstructions on the roof causing a problem, that's not that big a problem. Like others have said, proper placement will eliminate all but an occasional problem. With the physical limitations you have I'd be more worried about the panels being flat. But that to can be compensated for with the use of more panels. I to have the same physical limitation so with only 1 panel I choose to mount mine on the rear of the trailer so it can be tilted from the ground. When I get a couple more I will probably mount them on the roof. With that said, the 1 panel I have will charge my 4 gp24 batteries by 1-2pm on most days. If it wasn't for the need of a CPAP at night I could run without the generator. But I choose to run my genny about 1.5hrs before 10pm every night to make sure the batteries will last till dawn.

Hope this helps. I know how hard it is to decide on a solar system or not, then on which one. I read and read and ask a lot of questions for almost a year before I decided, then still second guessed myself. But in the end it made sense for me.

Hope this helps.

It's not just that experiences differ, it's that scenarios of use are different. Also, systems are different. Shading can be a problem, yes. If you expect a lot of shading and unsure of number of diodes in panels, it's better to wire panels in parallel. But this would complicate the installation - a thicker cable will be needed and very likely a roof junction box too.

I would've never got solar if were hesitating too much, but since solar was the only choice for me, solar I got. With trailer always in the open, and panels 12"-18" from the A/C, and lifted by 3"-4", it works well. One panel I actually had to lift because of 3" tall plumbing vent that was right under the panel, and a reduced shading came as an incidental effect. If possible, stay +18" from the A/C cover.

Keep in mind that shading from roof structures is a temporary effect that (with proper layout) would only occur on one panel out of 3 or 4, would affect only part of the total output, and would last an hour or less.

The first step, however, is not this, but sizing of the system. How many solar watts, how big battery bank. There were links on how to do this a few days ago, in the same DIY section, in a similar post. Don Pianotuna is always posting these links, and they are good. Mostly solar issues are discussed in Tech Issues, and I suspect that some "big guns" were not here because the topic was in DIY.

PS: the links:

Energy audit and sizing solar system, open XLSX file and click on the bottom tab "Solar Sizing" or "Battery Sizing": Solar Spread Sheet N8GS

Solar in simple terms:Golden rules of solar

No, I'm not shaking my head. As I said I have done much reading on the subject. Here is my take on things. Every one has their own opinion based on experience and what they believe of what they have read and been told. I am skeptical of posts that state no problems and unless I see data to back up claims I take it with a grain of salt. I do shake my head when posts go off topic or start dissing others for their opinions.
That said, I appreciate those who endeavor to understand my questions and relate their experience.

2oldman wrote:

Anyway, it's somewhat moot as my array is rarely shaded, and then only partially by my a/c hood.

Same here.

The OP is probably shaking his head and thinking "what the heck they are talking about, I just asked if I should get a solar" :)

OP: try and install your panels at least 1 ft from the A/C hood and 7"-8" from lower structures like vents. On a big 5-er with only 500-600W solar this should be possible.