Very Basic Solar set-up question

[optionguru]

I have a 15x30 workshop / storage building I use for my garbage company.  I mostly store tools and recycled copper and aluminum.  The shop has no power to it and I have a 80 watt solar panel I had bought a few years ago for kicks.

I need a few lights in the shop, they would only be used for a few hours a week.  Is there an easy way to set something up with the solar panel?

Thanks in advance for any ideas.
Peter

[glenn-k]

Sure is.  Hook the panel up to a battery, Preferably a deep cycle such as a Marine battery.  Observe proper polarity, + to +, - to -.   I assume you are all 12v system.  Go to Walmart or some place that carries cheap inverters.  Get about a 150 to 350 watt inverter.  Hook it to the battery.  It will have an on /off switch which you can use for your light switch.  Get a couple of clamp lights.  Clamp them in a convenient location and hook them together with light extension cords, then plug them into the inverter 120v plug in.  Screw compact florescent bulbs into the clamp light sockets - 100 watt equivalent draws around 23 watts each.  If you don't have a regulator, monitor battery voltage with a voltmeter daily and disconnect a lead from the panel when it is fully charged.  A cheap meter will work fine.  You can parallel 2 batteries for more storage and better use of your power if you find you are overcharging one.


Turn the inverter on when you need power.  Off when you don't to keep from pulling current when the lights are off.  Just leave the lights plugged in and use it for the light switch so put it in a convenient location when you set it up.  Note that it takes about 5 minutes for the lights to come up to full brightness but they work great and make best use of your free energy.

[phalynx]

if you go the compact flourescent route, don't get concerned when they hum.  They will hum with the cheap inverters.  All of the cheap inverters use a modified sinewave pattern which plays havoc with the ballasts on the CF bulbs.  But they will work.  It's better to have hum and the lights last a long time then to have no hum and the lights will last only a couple of hours....

[optionguru]

The overcharging had been a concern.  Is there an inexpensive product that will regulate the charging so I don't have to check on it daily?

[hnash53]

http://www.rain.org/~philfear/how2solar.html

Copy and paste this link into your browser.  This link is the one I used to set up may first very small solar system at my cabin.

It worked for me.

Best wishes.

Hal

[glenn-k]

Here are some pretty cheap ones.  You would be about 7 amps with 80 watts.  Go a bit extra - also consider if you will be going larger later.

http://www.nextag.com/serv/main/buyer/OutPDir.jsp?search=solar+charge+controller&psort=1

This one from that list would do it for $30.

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200265524_200265524

[optionguru]

For about $40 there's a 10amp controller, it doesn't mention the wattage it can accept.  Should I pay up for this slightly larger one or stick with the 7amp?

http://www.earthtechproducts.com/p193.html

Thank you all for your advice.

[MountainDon]

It may be wise to get a controller that would allow you to grow your system without having to replace the controller. You might find other uses for the power and need another panel.   :-/  

[glenn-k]

I agree with Don but if you are pretty sure you aren't adding more the small one would do it.

Watts = Volts x amps ... but the rating on the smaller one must have left room for peak voltage as they spec'd more than 100 watts.

[glenn-k]

Northern said the little controller would handle 7 of their 15 watt panels so it is even actually higher than rated as it will handle full output from 105 watts of panels as advertised.

[optionguru]

One more question, I think.  I set up the panel with a deep cycle battery and a 7 amp charge controller.  The panel isn't in direct light for much of the day, will it still charge some with ambient light?  I've had it hooked up and charging for 2 days and it doesn't seem to have done anything.  The yellow charge light illuminates on the charge controller.

Any ideas?

[MountainDon]

Panels work best with nice direct sunlight falling on all the cells. Shadows cause big drop off. Indirect light means much less charge.

[glenn-k]

I have about 800 watts on one controller.  Yesterday with cloud cover I was getting 25 watts for a while.  Any shadow on any part of the panel will shut down the entire panel.  For maximum output the panel should be about 90 degrees to the sun in other words the suns rays should strike it straight on - not a glancing blow.  This best angle varies daily as the sun rises higher.  I haven't optimized mine but bought extras.  For one you could change the angle every few weeks - stay within about 15 degrees or so of square.

[youngins]

Don't they have mechanisms to keep the panel in line with the sun?

[glenn-k]

They do for tons of money or you can make a home brew one cheaper.  Quite a project from getting flat panels on the roof and going to a tracker.  Appx  20 to 30% gain.  Choice is go to the trouble or buy more panels.

[outhouse]

I forget where I came across it, but this link helped with some confusing issues for me.  http://www.solaronline.com.au/page/solar_system_basics.html   I think this site has pretty good info, products, and prices.  http://www.affordable-solar.com/  

[MountainDon]

I think this site has pretty good info, products, and prices.  http://www.affordable-solar.com/  

Good place. They're local to me. One of three solar enterprises places I've had dealings with and recommend.

[glenn-k]

Their prices come in at under $5.00 per watt on many models which is right where it should be as prices have been increasing lately.  I have seen others charge up to double that.

[hnash53]

Uni-solar panels, and maybe others, have built-in bypass diodes which allow the portion of the panel that is still in direct sunlight to keep producing electricity while part of the panel is in the shade.

[glenn-k]

Do they use multiple bypass diodes in separate portions of the panel as 1 diode in the connection box usually takes out the whole panel I think?

[MountainDon]

UniSolar US-64 panels have "Bypass diodes are connected across each cell, allowing the modules to produce power even when partially shaded." (lifted from affordable solar website.) They are non-glass panels with thin-film amorphous photovoltaic cell technology.

Thin film cells use much less material in their manufacture. They are apparently slightly less efficient (don't recall the figures).

Here's an article from 2003....     http://www.aip.org/tip/INPHFA/vol-9/iss-2/p16.html

There have been some questions as to the thin film longevity, but I haven't any data to back or counter that claim.

Some people like the idea of no glass because they fear breakage of the glass in a standard panel. That should not be a worry as in the fall of 2004 Socorro, NM was hit with a giant hailstorm. I've read reports of glass fronted solar panels standing up to the up to 2 inch hailstones with no damage. Automobiles did not fare so well; there were over 8000 auto insurance claims, many totalled from having all glass broken followed by water damage, not to mention the body damage.