new here and love solar for my RV

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jimindenver

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Hi I am new here and honestly only use the trailer in the summer months. I have enjoyed putting together inexpensive portable solar set ups with panels I find of craigslist for as little as $50 each. There are the larger 24v panels that I mate with 20a solar cables and a 20a MPPT controller and the 245w mono panels are good for 17a each at 12v.

I started out with a 230w poly panel first paired with a 25 ft set of 10 gauge cables and a Eco-worthy 20a MPPT controller. The whole set up cost under $200 due to the low cost of the panel and the controller being the least expensive functioning MPPT controller available. Left flat it provided more than we needed for basic trailer functions plus some TV/DVD/Sat. It gets cool at 10000 ft and freezing at night, so our biggest draw was setting the stat at 74 degrees and leaving it there.

Tracking is another story. I could aim at the rising sun and have the battery in float by 9 am. After that I could turn on the furnace, all of the LED lights, both fans and the TV but the battery would stay in float. never losing voltage. The panel was providing enough to run the trailer on it's own.

That was neat so I bought a pair of 245w Mono panels for $85 each and created two portables. One can go one the trailers battery and the other on a old 8-D I use as a inverter bank. Combined and tracking they put out 34a on one bank and I used them to offset larger loads on the inverter. We run a auto drip coffee maker, a hair dryer, vacuum and even a 1375w microwave this way. The voltage sags but not like it would without the solar. On a sunny day it takes 10 minutes running the microwave to sag the 8-Ds voltage to 12v. Afterwards the recovery to float is 20-30 minutes.

Since the solar has done so well and we don't camp in the monsoon season, we leave our generator home. That meant that for the one trip mid summer when we could need the air conditioning, it wasn't available. So I found a window air conditioner that uses less than 400w and combined all three of our portables for 720w/ 50a with a 3000w inverter on the 8-D. As long as the sun shines, the panels will run the air conditioner without draining the battery. Luckily at that altitude if the sun isn't shining, you don't need air conditioning.

I had intended to mount the 245w monos but hated their output in anything but intense light. So I am in the process of selling off the portables for a matching set of polys to mount. I may still keep a portable as the ability to aim the panel is addicting.

As for the rest of it, we exclusively boondock at altitude in the Rockies. We tried having hook ups once but couldn't stand being crammed into a noisy, smelly campground. We tried a dry campground and people ran their generators day and night. Where we go we don't have neighbors for miles. We see no one, hear no one and never have to worry about them seeing or hearing us either. We usually go for up to a few weeks at a time, by then we need water and food.
 
So interesting. I have a generator on my rv that is used in summer and the noise is not part of the peacefulness I am seeking. Very seldom turn it on. Have a solar panel to install when I get my van. The passiveness of free solar (after investment) is so sweet. Thanks for sharing this info.
 
I think we were just lucky that when we went from a tent to a trailer that we didn't get the popular red inverter generator in a few ways. First is we couldn't justify the expense not knowing if we were going to like the trailer so we bought a affordable Champion open frame. I thought that since we would be the only ones to hear it that it would be ok. It was as long as we were inside making breakfast or running the air with a TV on. Being outside however was intolerable unless you were a good 100 ft away. I had to find a better way and not buying the expensive generator meant we had the funds to do so. The other is I didn't find out until this spring when we replaced the old unit that had I bought it, I would have a very expensive battery charger and not much more.

I have to say reading some of the post that I like the forum already. It's a lot more down to earth than some of the RV forums with the retirees, massive motor homes staying in resorts and unlimited budgets. My solutions are usually pretty basic and inexpensive and I learn what I need from forums like this. I'm always willing to offer help with what limited knowledge I have but usually by explaining how I do it and why.

YOu could use your panel portable as I do. All I use to keep it tilted is a pair of pine slates and a pair of C-clamps. Like I said, simple and cheap.
 
Thanks for all that great info Jim, good stuff! I know several people who do what you do and carry their panels inside and when they make camp set them out in the sun. Great system!! And like you said, easy to tilt and track.

Did you get your panels off craigslist?

Do you have a link to the 400 watt air conditioner? People here have been looking for a very low draw unit.

We're really glad you're here!
Bob
 
Bob

I did get the panels off of craigslist. They were install left overs and you might even call the installers in your area. Single 24v panels can't be used with others so they are almost useless to a home installer. Normal prices are on craigslist are $1 watt or less, super cheap are rare but happen.

The AC is a Frigidaire energy star 5000 BTU here.

http://www.amazon.com/Frigidaire-Wi...=8-2&keywords=frigidaire+5000+btu+energy+star

It is rated at 446w on high, that's 39 amps at 12v plus losses and the solar was covering around 33-35a while it ran. I'll put it on a Killawatt just to be sure.

Portables are nice for the ability to track and be in the sun while the trailer is shaded. The big panels can be a pain to handle and store. Pretty much the same can be done with a 200w kit from Eco-worthy or windy nation for $300 or less with shipping. Plug in in the wires and connect your battery and you are charging. Not all solar has to cost a fortune.

Out here there is a lot of NSF and BLM land that can be camped on for free. I'd go up in the spring and come down in the fall but the drive to work would be a killer.
 
I ran a kill a watt test on the AC today. Depending on settings it pulled between 390 and 410w. Using the low fan setting only drops it maybe 10w. That means that my twin 245w systems could run it on their own with no loss to the bank or minimal loss if they didn't.
 
jimindenver said:
I ran a kill a watt test on the AC today. Depending on settings it pulled between 390 and 410w. Using the low fan setting only drops it maybe 10w. That means that my twin 245w systems could run it on their own with no loss to the bank or minimal loss if they didn't.

I dont see it happening, but I might be wrong...

At 390 watts, running through an inverter, you're going to need anot 39AH to run your AC. That's including inverter loss.

If you have a total of 490 watts in solar panels, it's probably only going to do 392 watts in ideal conditions. That's 32 AH under ideal conditions. That doesn't include resistance and other losses throughout the system.

How often are you even going to have ideal conditions?

Just my thoughts, but I'm no expert...


I contacted the manufacturers of my panels, because the specs on the controller stated it would not handle more than 360 watts. He company packaged it with a 400 watt system. The company advised the most the panels could do was 340 watts, so the appropriate controller was used. That's a 15% loss right off the top.


Don't forget the 10% extra for recharging: if you take 39AH out, you'll need to put about 42.9 AH back in.


So I'm guessing you'll lose about 10AH an hour, under ideal conditions...
 
Your total 720 watts would probably run the AC under ideal conditions...
 
One thing to consider is that Jim is high in the mountains of Colorado and you get much closer to the ideal conditions there. At 10,000 feet you have much less atmosphere to interfere with the sun and it's much cooler on a fully sunshiny day.

I had a friend who went over a 12,000 foot pass in the fall in Colorado and it blew his controller and he called Blue Sky about it and they asked the conditions. When he described them they said the conditions were perfect with the altitude and cold to over-volt the controller.

The controller was properly sized for normal conditions but not perfect conditions. They sent him a new controller the next size up at no charge.

That's one reason why I recommend Blue Sky controllers.

But, even if the panels don't fully cover the full draw of the AC, just being close to covering it is amazing and it would still be enough to make it useable with a properly sized battery bank.
Bob
 
High altitude is neat, it gives solar a boost. the system cruses along around 48a and peaks slightly above 50a on cool clear day. Each controller is recording 210-220w at those times. Even if they can't cover it all, they can easily replace what the bank has to absorb for the short time we will need it.
 
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