Starting a solar panel system?

[Mental72]

I've read on posts here that the Harbor Freight solar panel kit that I've been drooling over for a while is crud. I looked around and found I could get 2 75 watt solar panels for $160 on ebay, and get a very basic $20 charge controller. So basically 45 watts vs 150 watts for the same price. I'm not good at math, numbers make my eye twitch, but even I could get that math. So if I could dig that up I wondered if any of you had any suggestions for what I could start with. Eventually I'd like to have solar and a little wind turbine system. If I keep the gaucho bed that's where I"m going to put the battery bank. I figure I'd go at it in stages. First I want to keep my craptop running off solar, then add to it until it will run my larger computer, that takes way too much juice to run. I have a triple monitor set up, and while they're not huge, they take a lot of power, and the 6 core proccessor and video card keep the room the computer is in so warm that I shut off the vent and have to keep the window open in the winter.

Thanks in advance for all your suggestions and advice.

[Stripe]

I have the 45 watt solar kit from HF and so far so good. I have used my 2k inverter from HF to power my Macbook Air.  The solar recharges what I use relatively quickly. My first trip up for training I didn't hook up my power to the 15 amp and just used battery power. Even in the (NOT) so sunny area of Custer, WA I was still pulling over 19v off the panels and 14.6 at the charge controller.  I have three DC marine batteries instead of the two the RV comes with so that I can run things longer.  When I first got the Panels it took a total of three days to put the batteries up to 13V, after that it was a matter of maintaining them. And now I keep the panels up on my dash (yes my dash IS that big, Lol) while she is parked and it maintains the batts when not being used.

As of this writing, I don't full time it in the RV and when she is parked at home, she gets plugged in.
So as far as all the things you want to run at once, that will most likely be dependent on your amount of batteries and the watt rating of your inverter.

I have a Toshiba Qosmio 18' Gaming laptop (great for Flight Sims with the main screen in the middle and two on either side) that draws around 180 watts. This precludes me from having to use a desktop PC that has a PS that draws upwards of 1080w.
I know that one of my LED monitors draws 60 Watts, just an FYI.  Your monitors will be different I am sure.
Clydesdalekevin and DaveVA78Chieftain have posted some good write-ups on solar.  Heed their advice, Kevin has been fulltiming it for years and Dave knows data info like the back of his hand..

Now as to Wind?  Unless you plan on carrying a pylon that you can put together and take down, I would not recommend putting a wind generator on your RV, it will rattle it apart.  This is one of the main reasons you are going to see fewer folks mounting WG's to their homes and having a dedicated pylon that can reach higher than three meters.

[ibdilbert01]

In my opinion the HF panels are not crud, you just don't get a good bang for your buck.   First they are only rated at 45 watts, and the output seems to vary from box to box.  They are also physically large for only being 45 watts.  Also as with most Chinese solar panels, they rate them incorrectly.   All solar panels should have a higher output until seasoned in, usually after the first year of use.   A good quality panel will be rated at its expected seasoned output.  Most Chinese panels are rated at what they can produce right off the assemble line.   They do work, and on average seem to last 7 to 10 weathered years before the "adhered on glass" technology starts to deteriorate.

The first generation charge controller that came with the kits were pretty much junk, the second generation and now the third seem to be "ok".   No thrills, just a "dumb" charger with a nice LED voltage display and some plugs on the front.

When purchasing panels, keep in mind there are three major players in the field.   

Amorphous (or thin film technology)
multi-crystalline (sometimes called poly crystalline)
mono-crystalline

There are more types, but these are the three main players.  Amorphous panels are usually your cheaper Chinese panels, but they do have a positive, and that is if made correctly, they tolerate shade and do a little bit better in ambient light.  They tend to be physically larger in size vs ratio of output and their life expectancy is not nearly as long as a crystalline panel.  Multi-crystalline panels are made up of of lots of individual pieces of PV Cells. They are cheaper to make than a monocrystalline panel, however more expensive than an amorphous panel. Because they are made up of pieces, they have a shattered glass appearance sometime mistaken for tiny cracks.  I like to tell people they have a foil look too them.  Though cheaper than Mono-crystalline Panels, they are just as reliable.  Mono-crystalline panels are probably the most expensive and in my opinion the best.    They also have a better space to output ratio.   Because they use slices of very pure silicone, they tend to cost more.

As far as charge controllers are concerned,  theres a lot of junk coming out of china these days.  Don't expect much out of a 20 dollar charge controller. 

The heart of your solar system is going to be your charge controller, don't skimp out on a cheap one.   A high quality PWM charger or better yet a MPPT is a must.    And be careful, there are Chinese controllers being sold on ebay marked at MPPT and they are not!

More info on MPPT vs PWM here:
https://www.youtube.com/watch?v=6W-_pDeNetA

[Mental72]

You guys rock. I'm looking into everything everyone said, thanks so much for your input.

[ClydesdaleKevin]

If you want to look into what I wrote, remember, 700 watt minimum flat mounted with no pivot, for fulltiming it. 

Kev

[Mental72]

I read a few places that when you aim the panels with a pan and tilt, you can increase output of the panels by 60%. One of the things I've found in my looking over the years is a thing called a heliostat. It's basically a solar tracking mirror, that keeps the sun reflected on a point through out the day. They seem nice for back windows on houses that don't get much sun, but I was thinking about seeing how much one or so would add to a solar panel set up, if anything.

Here's a neat open source project for heliostats and sun trackers I've found

http://cerebralmeltdown.com/Sun_Tracking_and_Heliostats/

As far as wind power goes, I was thinking that if I put up a 10' truss or pole on my roof, that would be about 20' (I have to measure how tall my rig is...). I was just thinking, it'd be better to have even a little something going into the batteries than nothing at all. I've read that treadmill motors work pretty decent for wind generators. I've been looking at some VAT (vertical wind turbines). I need to get the solar going first, of course, the wind was just something I was playing with in my head.

[Stripe]

VATs were over hyped as the new "thing" in wind power, they only ever capture about 50% of the winds power at best because while wind pushes one half of the blades one way, the others are fighting the wind to get back and are maybe 30% efficient, if your lucky. They are expensive, do not last anywhere near as long as horizontal wind generators and the cost to Kilowatt Hour is not worth the investment. They will however mesmerize you(actual studies have proven this).

As to tilting your panels and increasing your output, that depends on the panel(s) you use. And it's not so much as increasing output as it is maintaining the amount of sunlight that strikes the panels by maintaining the right angle for the time of year and what latitude you live at. You can either do the solar tracker thing, or just do it yourself.

If you go the auto tracker route, make sure you get a system that will not need a lot of maintenance. But ask yourself, how much energy will you be using in a day? How often will I stay somewhere long enough to need an auto tracker? Will it make getting something like that cost worthy?

[ClydesdaleKevin]

I plan on adding a hinge and tilt rods to our panels to get the maximum watts out of them...flat mounted the best I've ever got out of them is 370 watts, and they are rated at over 705 watts.  Now granted, the 240 or so I see in the winter sky in Arizona every year is still more than enough to supply all our power needs unless it gets cloudy.  Then on comes the genny for a few hours every 3 days.

Kev

[moonlitcoyote]

I would want to know why I was only getting 370 watts out of a 705 watt setup. There's a couple of wasted panels there. And I just read something about that. I'll have to see if I can find it again.

[ibdilbert01]

I would want to know why I was only getting 370 watts out of a 705 watt setup.   ...     There's a couple of wasted panels there.

Its because he has them flat mounted and isn't tilting them towards the sun.   That is why he said he planned on tilting them.   

[ClydesdaleKevin]

Yep.  For maximum efficiency, they have to be aimed at the sun, so that the sun is hitting them dead on. 

Kev

[moonlitcoyote]

Hmm, from what I read there shouldn't be a problem with panels flat mounted as long as there is no shadow on them

[ClydesdaleKevin]

A solar panel is most efficient when the sun is hitting it dead on at a 90 degree angle.

And that is how a panel is rated...in full sun with the sun right over the panel.

I'm quite happy with the performance of my panels flat mounted.  They generate more than I thought they would.  And we use a lot of power and don't skimp too much.  In the winter sun, even if cloudy, I only have to run my genny for about 3 hours every 3 days to bring the batteries back to a full charge with my Powermax Boondocker converter/charger.  In the summer I rarely have to run the genny, unless I want to run the AC.

Its a complex interrelated system.  Batteries, converter/charger, solar panels, charge controller, generator, inverter, and how much power you draw (or just how spartan you want to be with your power usage).

Which is the reason I want to make tilts for the panels.  I'm pretty spartan.  Patti?  Not so much...lol!

Kev

[DaveVA78Chieftain]

Thanks for providing that update Kevin.  I had been wondering how your system was working out.  Based on all the research I had done a while ago, I suspected your results were something like you indicated.

Dave

[Mental72]

Even with a very basic system, like manual adjustment for your tilt depending on what time of year it is and a manual pan that you went out and turned every so often during the day would be worth it to me for the increased output. MORE POWER.