# Bargain in a solar shed system



## genebo (Sep 12, 2004)

Harbor Freaight has their 45 watt solar kit on sale in the store only for $199.95. Comes with a regulator and two 5 watt flourescent lights. Add a 12 volt battery and you'll have lights for your shed.

I've had one for several years and like it, so I bought another one.

Genebo


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## wy_white_wolf (Oct 14, 2004)

Replace the charge controller with a Morningstar SL10-12 and you'll be able to add lighting a couple of hours a day to your chicken coop to up the egg production in the winter.


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## cowboy joe (Sep 14, 2003)

I bought one of these over the summer and hope to finish the homemade charge controller this winter. If you sign up for their "Specials" they sometimes send discount coupons. I received one for 15% off a single item and waited until the panel went on sale so I only pair ~$170 + tax. Either way, not a bad price especially to experiment a little.


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## Windy in Kansas (Jun 16, 2002)

A 45 watt panel set for 6 hours per day should yield 270 watt hours if used to charge a battery.

Seems like such a set up should run a little more than two 5 watt bulbs full time, 8 hours per day much more.

Do the panels perform at approximately the rated output? I have looked at them in the retail store but was never very impressed.


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## wy_white_wolf (Oct 14, 2004)

National average is 4 hours per day insolation. Many areas receive less than 2 in the winter so the oversize you see is just trying to cover everyone. You also need to figure about a 30 to 35% ineffiecency factor with the cheap controller and batteries.

So for 4 hours that would be 180 watts production and about 130 usable. Half that in the winter for many areas.


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## Windy in Kansas (Jun 16, 2002)

Thanks. I had figured a 10 day would net about 6. Guess I can understand why a tracker used on the larger systems is justified.


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## CarlieHedges (Oct 8, 2008)

I use this for my ag building! We've gone through two of their controllers though. The first made a horrible screeching noise and I took it back to the store and they just swapped it out from another kit. The second one lasted about 6 months. To be honest I'm not sure when it stopped working since I didn't really need it during the summer months except after dark if I was in the barn. I needed a bigger controller anyhow since I plan to purchase another of their kits this weekend.


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## genebo (Sep 12, 2004)

I've had mine for several years, and I got a screeching sound whenever the controller kicked out for "overcharge" at 13.5 volts. This happened a lot during the summer and I got tired of listening to it, so I replaced the controller with another brand. End of problem.

I quit using the flourescent lights that came with the kit, because they didn't want to start in really cold weather. I now have two 3W 36 LED flood lights in the hen house, a 5w halogen in the barn, and 2 65W tractor work lights facing out over the barnyard. I turn the tractor lights on each night for about 20-30 minutes.

I get a lot of light from the LED lights, a dim light from the halogen, and the tractor lights are just like car headlamps, except with a wider pattern. They're bright.

I have one Exide 12v 720ah marine battery that everything operates from. The solar panel keeps it charged all year round. We're supposed to get 5 hours of good sun here in Virginia, minimum. However much we get, it's enough.

Oh, I also have a 1200w inverter that will run a 1/4" drill motor or a skil saw, a small fan or a TV set. I don't use it much, and I've never seen where it made any appreciable drain on the battery. Mostly it's turned off.

Genebo


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## cowboy joe (Sep 14, 2003)

Windy in Kansas said:


> Do the panels perform at approximately the rated output? I have looked at them in the retail store but was never very impressed.


According to the test I did, the panels are closer to 35W in full sun during the summer. They might perform a touch better during cooler weather.

The controller supplied with the unit appears to be very basic with only one mode for bulk charge. I've noticed that the unit I have exhibits some odd behaviors so I'm designing a switchmode charger with trickle, bulk and float modes to prevent damage to the batteries.


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## wy_white_wolf (Oct 14, 2004)

> I have one Exide 12v 720ah marine battery


That has to be a typo. A 12v 720ah battery would wiegh close to 500 pounds and 45 watts of solar wouldn't even handle the self discharge rate. Maybe 720cca which has no useful purpose when talking solar. 

All of Virgina is in the 2-3 range average for January.

http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/Table.html
click "view the map" at bottom of page.

Glad to here it is working for you.


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## genebo (Sep 12, 2004)

You're right about the typo, except it wasn't a typo, it was a mistake on my part. I stated the cranking amps instead of the amp hours. The battery is marked as 100ah.

Genebo


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## CarlieHedges (Oct 8, 2008)

What about the Morningstar SS10-L? Would that do okay for two of these systems combined? I'm not necessarily concerned about having lights go on/off at specific times. This being a controller only while the SL model being a lighting controller?


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## wy_white_wolf (Oct 14, 2004)

CarlieHedges said:


> What about the Morningstar SS10-L? Would that do okay for two of these systems combined? I'm not necessarily concerned about having lights go on/off at specific times. This being a controller only while the SL model being a lighting controller?


There's 3 methods for figuring controller size. One quick and dirty and one that is more accurate as it accounts for the charactoristics of the panel and one used by code.

Quick and dirty is you figure at least 1 amp of controller for every 10 watts of array on a 12 volt system. 2 kits would be 90 watts divided by 10 would be 9 amps. So the SS10-12 should work.

Now the better way. You need at least 125% of the STC (short circut current). I don't have one of these panels so I don't have the STC rating. I did find they are rated at 850ma so will use that. 2 kits would be 6 panels. so .85a times 6 times 1.25 = 6.375amps. The SS10-12 will handle that.

The 3 method is way to complicated to get into here but it also compinsates (sp?) for cold temperatures.

WWW


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