simple yard system for newb

System · August 2007

hey all. I am new to the site and alittle new to the solar stuff. What I have is solar lights in the yard. The little panels they give me are too small for what I'd like. I bought a 15w panel awhile back and I have a nice deep cell batt. already. I went online today and bought a charge controller, and I already own a small 750w inverter. Now, I have 12 lights. These are the ones I got,

http://www.lowes.com/lowes/lkn?action=productDetail&productId=9091-251-LZ635RPL4&lpage=none.

My question is this: How do I hook all this stuff up to work right? Do I put the panel onthe roof, run wire to the charge controller and then to the battery. Then what? Can I just get a small transformer for yard lights like this,

http://www.lowes.com/lowes/lkn?action=productDetail&productId=72830-251-ML200T&lpage=none

and then hook up the 12 lights to it. Now, I prob need atleast 2 more panels, which is not a big deal. But I just need an understanding of how this works. I am reading all that I can to understand and so far, this site is really informative. Thanks for the help.

System2 · August 2007

Re: simple yard system for newb

i see 17 people have read my post, and none have left a comment. I have read around this forum and haven't found nothing yet. Someone please clarify if I know what I am doing or is it more involved than what I think it is.

BB. · August 2007

Re: simple yard system for newb

I read your post--but I was not quite sure how to address it...

The first link you posted is to a "stand a lone" solar power lighting system. It appears that (guessing here) the solar panel has some batteries (probably NiCAD) and you wire it up to the for lights (probably LED). So, there is nothing else to do with this set.

The second link is to a 200 watt transformer with timer. Normally, this would connect to your house wiring as you need 24/7 power to keep the timer accurate and it takes 120 VAC and drops it down to (around) 12 VAC. I kind of doubt that this would properly run the lights in the first link (probably 2-3 VDC LED lights).

While you could rig a solar PV system + inverter and make it run--it would probably cost (in solar panels, charge controller, inverter, and batteries) more than you would really want to spend.

Now, the "typical" LED + Solar panel yard light sets are very dim--because the panels are small, they can't have bright lights. Also, these systems are built inexpensive--typically, they don't have charge controllers and such--but just a pair of NiCAD cells in series (to generate ~2-3 VDC), charged with the small solar panel(s). The NiCADs and panels will charge fine--but NiCADs can also be (pretty safely) discharged 100% and still have good life (1-3 years in your yard lights).

Now, with a Lead Acid battery, it cannot be overcharged, or discharged beyond about 50% capacity or you will quickly kill it (few weeks or months). So the charger/controller electronics need to be fairly sophisticated.

You would probably need something like this (see bottom of page for Solar lighting charge controllers)--if you want unified solution (recommended for your small system). All you would need is the solar panel(s) and the light(s).

Sizing--depending on where you life and how much sun you get (Illinois?), you can look up how much sun you get--Let's guess at around 3-5 hours per day (winter-summer).

Now, while you can run any bulb you want--the controllers I listed are either 12 or 24 VDC, and generally, you want to run LED as they can be much more efficient than incandescent lamps. Disadvantage to LED's, is white LED need around 3-3.5 VDC whereas incandescent can be purchased to run at 12 Volts AC or DC.

We can further discuss where/what LED lamps you want--but for this discussion lets pick 3 watt LEDs (at 12 VDC) and 12 of them.

Now, just to make things easy, lets assume all of the various efficiencies work out that the system is about 50% efficient (could be 60-70% efficient too--but I am going to over size the system a bit so that you get something that will, for sure, better meet your needs).

To calculate the size of the solar panel (in watts) you will need. Let's assume that you want to work in Winter for 5 hours per night and you average 3 hours of sun per day (from 2nd link).

PV Watts = 3w*12 lights * 5 hours of light / (50% eff * 3 hours of sun) = 120 watt panel

Size of battery--Assuming that this is a lead acid battery, we only want to drain it to 50% capacity on a regular basis and you want to "survive" 3 days without sun (to give long battery life). Also, it would be best if the battery is kept in the house/garage/basement--well ventilated--as you don't want it to freeze, plus lead/acid batteries don't do real well in the cold. Batteries are rated in Amp*Hours:

Battery=3w*12Lights*5hours/day*3days/(50% cap*12volts)=90 Amp*Hours

This sort of addresses the basic issues, and you can change the numbers to suit your needs.

There are still the details of what type of battery (an AGM may be a better choice here), and what LED lamps to use (some types are much more efficient than others).

Mounting the solar panel? Mount it in full sun, facing south. Tilt it up to about 50-60 degrees so that it collects the winter sun and better sheds snow (if you get much were you live).

Does this give you a better start? I have not used the solar controllers in the 2nd link--but I believe that they would be a good place to start (find the manual for one of them and download it to read for the details on installation of the system).

-Bill

niel · August 2007

Re: simple yard system for newb

bbsccr01,
bill is right in that we didn't exactly know how to address this. you make mention of the small systems that are a few volts and then wish to expand on them with a 12v 15w pv and, a name and model # unknown to us, controller. then you tell us you have purchased a 750w inverter for high voltage ac.
this is a case that i believe that you should've looked before you leaped by asking us advice before you bought. i know that i still don't know what to tell you seeing as how you've made purchases that go in 3 different directions.

System2 · August 2007

Re: simple yard system for newb

well, this is alittle more complicated than I thought. I bought the inverter along time ago. it was bought for another use, and I thought I could use it for this application. Now I know I can't. Now, along with the batt. its a gel cell that was purchased about 2 years ago and again, I thought that i could use it for this application. I did however buy a charge controller. I will link the site when I get home to show what I bought. I am at work now and can't remember what I did actually buy. I have really no understanding of the difference between the "stand alone" that I have and turning it into a network of lights. I thought solar power was, well solar. And now I see that its not that easy. after reading what was posted by me and others, I can see where I didnt give enough info for you to really help me. But I thank those who did try to point me into the right direction.

Now, let me start over. With the lights that I have, what can I do with them to make them more effecient? The are rechargable batts. The Nicad, I think. But, Is there anything that can be done to make my yard have lights for atleast 5 hours. If feasable. I live in FL by the way. Any help is really appreciated.

System2 · August 2007

Re: simple yard system for newb

or start over from scratch. what kind of lighting system could I get for my yard? It don't matter what I got or not. what would I have to buy. and then what kind of lights. when I can find more time, I will read more into solar and how it all goes together. is there alink that can be posted or sent my way for me to get abetter understanding of this?

BB. · August 2007

Re: simple yard system for newb

Generally, with solar power, your first efforts would be to find(or build) the most efficient lights you can. Normally, that would beLED's designed to run at your system's voltage... Ideally, you would want the best light to watt ratio you can get.

And, there are several ways you can get 12 vdc LED's... 1. you find an efficient 12 vdc LED fixture that meets your needs. 2. you purchase 12vdc LEDs (or even florescent assembles). 3. you build your own with LEDs and DC to DC type converters (or several LEDs in series with a resistor) designed to take 12 vdc in and power your LED's with ~3.5 vdc or so (the details do matter--don't know if you want to go there for this project).

Once you know what lights you want (numbers and power requirements),then figuring out the battery, charge controller, and solar panel size(based on where you live) is next. And those formulas I posted earlier,will do that well enough for a first cut to predict costs and hardware requirements.

Generally, solar lighting is going to be the most cost effective whenit costs more to run the power to the location than it would cost tobuild a stand-a-lone solar system.

I would still recommend, as a start, if you are going to use 12 VDC lighting, that you look at the Morning Star controller I referenced earlier... Here is the Morning Star web site with operator's manual:

http://www.morningstarcorp.com/products/SunLight/index.shtml

It seems that it is a great way to start if you want to have a turn-key controller for solar powered landscape lighting.

The system you linked to it not designed to be expanded--and generally, uses the smallest LED's they can so that they can keep the expensive components cheap (solar panel and batteries).

I think there are a couple people here that have solar powered landscape lighting--perhaps they can point you to some useful solar capable outdoor fixtures.

Wind-Sun has a few florescent outdoor fixtures--and perhaps they can point you to other fixtures they may have that I did not find.

http://store.solar-electric.com/thinlites.html

-Bill

niel · August 2007

Re: simple yard system for newb

i'm going to comment somewhat on the initial solar lights that you have. in general i have seen in my general part of the neighborhood that others are copying me in getting solar lights. good i say, but they can't put them on the northern side of their property with their homes shading the lights and expect them to work like mine for that part of the property does not receive much sunlight and as such receives little power to keep their batteries charged. (especially in winter) they soon start to dieoff and this shows up initially as a shortened timespan of lightgiving. i see that yours is at 5hrs and they generally should last at least 7-8hrs that they were designed for. (do note that the nights in and adjacent to winter are longer than this meaning shorter charge times and longer operation times. why they would under rate them, i don't know.) if you just bought these lights and this is the performance you are getting during the longer summer days, then i'll advise you to take them back as being defective providing you didn't place them into a more shaded area of your property such as the northern side or even under trees and bushes(yes, i've seen people do this with solar lights).

simple yard system for newb

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