Energy storage for Landscape lighting

[merkurmaniac]

I have two smallish solar panels that I bought to try out some ideas.  Now, I am thinking about adding some landscape lighting to my house and powering it with the solar panels on its own independant circuit from my house.  I like the idea of gathering solar power and storing it in DC and then running the lamps when the sun goes down (also in DC) without any transformers, etc...  Since the landscape lighting is not critical by any means, and could be dimmed or peter out by morning altogether and not be missed, it might be an easier introduction into solar power controls and storage.

THe problem is, I have read enough to realize that partially charging (or fully charging) and then totally depleting batteries once a day would be tremendously hard on them, is there another energy storage means, perhaps a capacitor, that would handle this kind of service ??  In other words, a smarter solution that ruining a lead acid battery as it charges and discharges on a daily basis.

I was planning on jsut using a photocell as a switch to run a relay, I guess.  The system would store energy when the sun was out, and discharge all available energy when the sun went down.  If the lights only lasted a couple of hours before the jiuce was all used up, then no big deal.

I just like the idea of using my solar power to power my "frivoulous" exterior lighting .

Thanks,

First post from a long time lurker,

Richard

[skravlinge]

If your aim is to experiment in storing solar, this may not be of any help, but if you want to light up the landscape I know of small lamps wich collect the solar on daytime and not light then, and shine when its dark. They are not very expency.

[wooferhound]

You could modify the outdoore light fixtures to use LEDs

Not really a lot of light but it could possably run all night.

[merkurmaniac]

I was kind of thinking about dabbling in LEDs, but I would like to get some of the basics figured out before I do that.  A guy down the street has some of the solar powered lawn lights.  There are many problems with them.  First, each has its own small collector that sits on top of the light, maybe in the shade during the day.  Each unit also has its own small battery, so I need X number of batteries.  I would rather have one large battery and one large solar collector in a sunny spot.  The lamps down the street are quite dim, I might shoot for something a little more powerfull.

Anyone know what kind of batteries these stand-alone commercially available ones have ?  What kind of energy storage would be best suited for this kind of lifestyle of daily cahrge and then total drain ?

R.T.

[hvirtane]

Anyone know what kind of batteries these stand-alone commercially available ones have?  What kind of energy storage would be best suited for this kind of lifestyle of daily charge and then total drain?

I've seen such led garden lights

with AA size batteries.

I think that they are

made so that they don't drain

the batteries completely.

You can probably modify them

so that you could

use a bigger common

battery for many lights.

- Hannu

[jtbartlett]

Won't an electric timer take care of your problems? If you set the on/off cycle appropriately you will not run the risk of fully depleting the batteries. Just trying to help.

[test lab guy]

I have to agree with jtb.  Do not totally drain the battery, although it's a very good way to make battery door stops.  The 12 volt to 110 vac inverters that are everywhere on ebay for 10 cents a watt shut down at 10 volts, or approximately 84% depletion. This is even in the safe operating range of AGM batteries.

$.02

TLG

[Mentally Moribund]

Ni-Cad batteries will take the torcher for about a year before going down hill in performance.  This is also what the commercial solar lights use.  Partsexpress.com carries many types and sizes of batteries with decent pricing.

[merkurmaniac]

I don't want to do an inverter, if it comes to that, I'll just run off the grid.  I want to do it with the native current of the solar panels.

Perhaps what I will shoot for is a timer that would kick the lights on for several (say three or four hours) after sundown, and then stop the circuit until the next charging cycle is over.  Perhaps if I use LEDs I might be able to get by with some relaviely small Ni-Cad batteries.  If I used an old car battery and had a timer that shut down when the voltage dropped by say...30%, perhaps it would last a while.

My solar panels were bought on eBay a while back and are about 14"x14" qty 2.  12V is probably ambitious for these two panels anyways,... I guess that I should start by measuring the volage that they put out.

[nothing to lose]

Well I have about a 6" X 13" 6volt pannel from an electric fence charger that put out over 10volts open when in direct sun on a bright day. I forget what the max was and such, It runs a 12v computer fan directly from the pannel but it wasn't full speed. Useable though, it's going into a solar heater, when sun shines I get heat and the fan move it along slowly and when the sun quits I have no heat and the fan stops too. Couldn't ask for more

The post on it here.

http://www.fieldlines.com/story/2004/11/5/104215/348

Anyway if yours work as good as mine you should be able to double them up, and if each is supposed to be 12V you shouldn't need to anyway.

Just an idea, maybe use a motion senser on them, then they only turn on when something is moving around after dark, like a dog or cat walks by.

Make flashing lights. Not sure what he did exactly, but a friend once made a couple lights flash by using light sensors. During the day they were off, at night they tried to turn on, but....

No light they turned on, then they either saw their own light or the light next to them and turned back off. This caused several lights to flash on and off independantly as they wanted. Was kinda neat effect and attention getter too.

Also being as most the time only half the lights were on he used alittle more than half the power, so maybe your lights would burn twice as long if you don't mind the random flashing.