solar powered fifth-wheel?

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mjfinn1964

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Mar 7, 2012
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Hi all. I am considering adding a solar power system to my fifth-wheel so it is independent of generator  (gasoline-driven power) when dry-camping. Has anyone done this and what kinds of unexpected issues did you encounter? How did you affix it to the top of the trailer so the panels could be repositioned? (Or did you just reposition the whole trailer?) Did you have to reinforce the roof? Thanks! ~Melinda
 
There are lots of threads on solar power on here, use the search button in the menu bar.

In short, you need more space than your roof allows to be self sufficient on solar alone. There are a lot of variables to consider. And to top it off the expense is tremendous.

It can be done if your expectations are reasonable, but you will not be living on an unlimited amount of power.

Steve
 
Being able to install solar panels and not use a generator is still years in the future. If it were possible then a huge amount of RVs would be doing it. CaptSteve is correct, your roof isn't big enough, solar power is way too inefficient and the cost is way too high with the current technology.
 
I generally agree with the others, with the caveat that it depends on your energy needs, what I call your "energy budget". If you want to use air conditioning, make extensive use of electric appliances (including a computer & tv), or use a lights for many hours daily, you will probably not have adequate power. Air conditioners in particular use huge amounts of power and are impractical to run except via shore power or generator.

Solar can produce only so much power, even if you cover the roof with top-quality panels. You also have to have a battery bank capable of storing that power for the many hours/day when the sun isn't shining directly on the panels. Then you need a large inverter to convert the stored DC power to 120vac for your household electric appliances, but an inverter is only about 90% efficient, so there is a substantial loss in the conversion.

Assuming your needs are within the capabilities of a solar + battery system you can afford, the technical problems are few. Modern RV roofs are easily capable of supporting the panels, which can be screwed or glued top the surface. Running the wiring down to the battery bank(s) sometimes requires a bit of creativity in the routing, but is seldom a big challenge. Finding space for enough batteries and carrying the extra battery weight may be the toughest part, but that depends on how much power storage you need. If 2-4 batteries will handle it, it should not be a problem.

As for orienting the panels, most people don't. If you are parking long term in an open area, you can orient the trailer to the optimum position. You probably wouldn't climb up on the roof to adjust panels anyway.
 
Run the air conditioner, not out of the question but unpractical. It takes a huge battery bank to store the energy to even run the AC short term and a lot of solar to recharge it. One person I know has the bank and inverter to do it but only 250w of solar an the recharge would take days. He does however heat his rv with electric heaters off of his bank and inverter.

Other than that I know of a few people that run their rigs off of solar. They have large banks and inverters that run residential refrigerators, microwaves, coffee pots, toasters, TVs and dishes... much more than I do with my solar which is just keep my battery bank up. I have a inverter but my TV, DVD, and various chargers (phone, laptop, other batteries etc) are all 12v.

The cost of solar has never been cheaper too. Buying kits or having a dealer install them is still outrageous but you can pick up the panels, wiring, controller and other bits for a fraction off of ebay and craigslist. I got lucky and found 450 watts of panels for $100 on craigslist and generally can find panels at under $1 a watt locally. Company's like solarblvd.com sell the panels cheap plus shipping. I think their last sale was a 250w panel for $150 plus shipping, two panels would be $130 for shipping meaning 500w for a total of $430.  Controller cost is controlled by the type of panel and the size of the installation. More watts = bigger more expensive controller.

I use a single 230w panel left portable, a 380ah battery bank and a 20a MPPT controller.  This allows me to have the rig in the shade and the panel in the sun. I can also start tracking the sun at dawn adjusting every so often to maintain the maximum exposure. With a bank big enough to hold us over for 4 or 5 days of rain and enough watts to recharge it in one day even if it's partially cloudy, I doubt I'll run the generator aside from exercising it and the need of AC.  BTW I have spent under $500 on my system. I can see 10-15 amps charging from dawn to dusk tracking and over 8 amps if mounted flat.

Most people mount flat, others hinge the panel so you can tilt for better mid day exposure to the south. Tilting and rotating on the roof would be complicated and require many trips on the roof for adjustments but it can be done.

So it boils down to how much do you want your system to do for you, how much power do you use and how much money are you willing to spend?

 
Read this entire site, should answer all your questions.  http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/
 
I can only tell what I have done, what I do and describe my system. I have 4 150 watt panels permanently mounted--no swivels- on my roof and room for at 3 more. I mounted them solid because I do not want to cclimb on the roof just for the extra 10-15% uotput. I have a 3 stage charger,4 225 amp-hour 6 volt batteries and a 1500 watt pure sine wave inverter. iI the summer in Montana, we did not hook up or run a generator for over a month. We watched TV, used 2 laptops, and used the microwave for short periods-less than 5 minutes just to warm something up, plus all the normal stuff--lights (non-LED), water pump and parasitic drain. This winter, the system could not keep up with demand, so we hooked up when possible. I think that if I had put up the other 3 panels that i have room for, it would work in the winter. So, when people tell you that you can not power a RV with only solar power, they are correct. You can not run air conditioners, electric heaters, or other long running heavy draw items. You have to choose where you park, with shade in mind. You need to keep power use in line with your system. And, in the winter, because of less sunlight, you might need to hook up oor run a generator once a week or so to keep a good charge (12.5+ volts) in your batteries. We have been using this system for only 8 months or so. If I had it to do over, I would put in 3 more panels. The reason I haven't is because I built the system when I was still working and drawing social security and had money available. Now that I have retired, I do not have the spare cash to buy the panels and upgrade the charger. The system has given us oppourtunites to boondock for extended periods, but we still need to hookup and go empty the holding tanks and get water.
 
Wow! Thanks everyone for the feedback, -and thanks for the link! Since our "camping weather" season is only about six weeks here, my family and I will be relying on the fifth-wheel more  ;Das an alternative living area when the power is out (often for more than a week at a time) or when the teen-age daughter has sleep-overs or guests. We have a large generator (and a wood stove) for the house, but one of the things we discovered after our Nisqually quake in 2001, and a few bad wind storms (70+ mph winds/freezing rain/snow) is that, once our 50 gallon supply of gasoline was used, we had to travel up to 50 miles to find more while the power was out. The same goes for potable water. (Our well water turned to mud for over a week after the quake.)

As far as a solar system goes, I don't have an air conditioner (don't need one) but will need the heater. I have converted the lights to LED so they use only tiny bits of power, and the only other power sucker may be a television or the microwave, and the pump for the water. The refrigerator, hot water heater, and furnace have propane or electric power options.  So, it looks like this may be doable! -Even if the little generator has to be used once in a while to recharge batteries or to run the furnace, it will still use less gas...Thanks for the feedback...Now off to research more...:)

 
There are two parts to this equation and conservation , use of LED's, in our case I used an Espar diesel heater and I use computer case fans (small trailer). The other half is solar and perhaps one of the bes sources is Handy Bob http://handybobsolar.wordpress.com/ and yes you can have enough solar area on a 5er, he did. 
 
Thank you so much for this link! Right now, I feel I cannot read/research enough as, since this will be a bit of an investment, I want to do it right the first time. If nothing else, I am learning how much I don't know... ;)
 
Handy Bob is a good resource. Yes you can use solar and there are two parts of the equation, current generation and current conservation. We have a large teardrop trailer with a 185W high voltage panel and Morningstar MPPT controller. All LED lights and when off grid use propane for cooking, water heater, grill. But we do have a 300W Morningstar Sursine inverter to power TV and charge laptop... We have never gotten below 73% depth of discharge.
 
:D Thank you, Shadow Catcher! I have just read up about inverters and how they work with the electrical system in my RV.  For the first time, I clearly understand the difference between AC and DC power, how DC is converted to AC, the importance of sine waves, and how to figure out how much "juice storage" I may need to run stuff when the generator or solar panels are not charging things. Very interesting stuff. -I can't quite build rockets yet, but I'm getting there! :)
 
RV isn't solar powered but my sticks and bricks are. I know technology has moved forward but 400watts of panels is quite a large area required.

http://i44.tinypic.com/j0g11j.jpg

I live comfortable with  a 4kw inverter with 120 VAC output. I do have a step up transformer for the 220 required for the well pump. But everything else is coverted to 120VAC. As for batteries I've got a 1,000 pounds of batteries 24 volt system 820 AmpHours worth of power.

http://i54.tinypic.com/2d8lsom.jpg

Devices that create heat typically are the tough ones. Like a 1,500w heater or coffee maker will draw 125 Amps DC (12 volt DC) or 62.5 Amps DC (24 volt DC). Being we are talking RV the idea of any large load or large battery banks are going to be out of the question I think. This why I think my 400w little inverter is excellent for the RV because even with my two 12V batteries I might have about 100-150 Amp/hours of battery with the 400w inverter load...

12 Volts DC x 33.3 Amps DC = 400w = 120 Volts AC x 3.33 Amps AC
 
I have two 125 watt panels and 4-6VDC golf cart batteries on my fiver.  The panels are bolted to the roof.  I simply don't worry about trying to gain maximum sun.  If I was that worried there are probably 99% of the places I like to camp that i could no longer go.with a proper setup, even on cloudy days you will still see gains.  Maybe not full power, but gains non the less.  Even with solar i still carry a generator with me.  One just never knows when it will be necessary.
 
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