Outdoor Solar Lights

Alright, my buddy is going off to college, and I’d like to make something for him.

Here’s my idea: I’m hollow out a cheap harmonica, put a solar cell and photoresistor on top, and place a 10 LED’s in the holes that will glow when the lights are turned off.

Here’s how I plan to set this up: I’m going to take 3 of these: http://www.radioshack.com/product/index.jsp?productId=2062564 solar cells (totaling 1.5V together) and hardwire them to a 1.2V rechargable AAA battery.

The I will have another wire going into a photoresistor cell in front of the LED’s and back into the the 1.5V battery.

If you are confused: there are two loops going into the battery – one with the solar cell, one with the LED’s.

So, I have a couple questions:

1) – will the AAA battery charge with the solar cells – his dorm will be in Seattle, so direct sunlight is doubtful.

2)-If the solar cell can charge the battery, will it be enough to light 10 LED’s for a few hours?

3)-If the solar cell can charge the battery, will the photoresistor cell and the LED’s drain the battery before there is enough charge to hold the lights in the dark?
Will the LED’s drain it to the point that it doesn’t work if I were to take out the photoresistor cell?

No, such a system cannot store enough power to light 10 LEDs for any length of time. The solar accent lights sold for dotting the garden do not collect enough charge even in the tropics in direct sunlight to keep the single LED burning for more than four to five hours.

Its for a solar panel with really low voltage that can only produce about 30 to on a sunny day 50 micro amps. Im looking for a led light that would prove that is working besides an amp meter.

Lowest you are going to find is 1-2 mA.

You may be able to use a capacitor discharge method, and there may be IC’s that do that. That is, you store charge in a cap and use that to blink the LED every few seconds.

here is a circuit i found.

http://www.discovercircuits.com/PDF-FILES/3vledfs1.pdf

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I have two garden solar LED light systems. Each one is powered by one AA battery. I plan on using the bulbs for an RC car project, but i seem to be having problems. Im not a tech guy or nothin so im kinda lost when it comes to this stuff. Here is my problem. I want both bulbs to run off of the same battery, without one loosing power or getting dim. So far what ive done is just , taken off the curcuit board and attached the two wires from one LED to the other LED’s connections. I know there is something im missing, just dont know what. I really want to avoid using another battery as it adds weight to my rc car. Any tips or suggestions would be greatly appreciated.

thanks

First, LEDs are polarity sensitive, meaning they have a + and – side. If you look at the LED from the side you’ll notice a flat spot at the base of the LED. This is the negative side or the bigger metal part inside the LED is also negative.

You also must have a current limiting resister in most cases. In your case you may find it difficult to get the LED to light up from 1.5 volts as the voltage to light one is typically 3 volts.

This will help http://led.linear1.org/led.wiz

I’ve looked on packaging of several models of solar LED lighting, and can’t find any kind of information on brightness. How is that determined?

Good question. I bought a small solar powered spot to illuminate my house numbers a few years ago and it was so dim, I had to buy another. Even if they labeled them dim, dimmer and dimmest it would be of some help. RScott

My friend owns a store here in Minneapolis called The Green Goober.
Her sign does not light up at night very well, and she needs more light… Shes looking to put up LED lights and solar panels strictly to power them.

Does anyone know where to find such a think/how much wattage LED lights need?

Any help is greatly appreciated

Of course, night lights can only be powered by solar by having batteries to hold the power from day to night. Practically, that means using standard 12 volt panels with a charging regulator. The solar panel is rated in watts, but the amount of sun in Minneapolis in winter is rather low, so a store selling them is going to have to provide data on output there. The nights are long, which means more batteries for storage and more charging each day. LED floods and area lights are not that common, so no real answer is possible – unless she plans on outlining the sign parts with individual LED’s Power of those can range from a few watts way, way, down.

I have been looking at solar cells. I am having a hard time to find out how much power a solar cell uses from a car battery. I was just wondering if you could create a cycle where the system can just recharge it self for a long period of time.

No

Led bright is not enough to get power from solar cell

You Can’t get high Energy from low Energy

I have a dozen very nice solar lawn lights that I’d like to convert to
AC power. The conditions, both solar exposure and temperature here in
Wisconsin mean that these things run out of juice before the morning.
Sure seems like it shouldn’t be rocket science to convert to AC power.

solution:

You burry a cable connecting (in parallel) all lamps to a one spot, preferably
inside the house or in a sheltered spot. At that spot they will be connected to
a 3 V DC power.

This is basicaly inventorbob-ga’s solution 1). I discourage
solution 2) since it is not a ‘low voltage’ solution. There are safety
and code problems with solution 2).

The cable which can be burried is sold in an Home Depo and similar
stores (which carry automatic sprinklers). They can be used for 120V
and of course for any lover voltage. There are however some local
ordonances (if I remember correctly, there is a minimal depth (about
10") )

Make and keep drawing of the curcuit (for case of future digging ..)

You can add a central recharchable battery and a simple regulator
circuit which will charge it (from your power supply) only when
needed.

You can add such regularor to each local battery in circuit
circuit in From: inventorbob-ga on 11 Oct 2006 08:28 PDT case 1)

With such regulator you can have several branches connected to your power supply
or central batery.
Regulators prevent the local batteries from discharching by any other
path than to their local LED light (eliminating possible local loops).

Regulator can be just a diode (allowing the current to flow only one way) or
a slightly more complex circuit which will enable charging only when the
voltage of local battey drops to certan level.

There are codes which cover outside wiring. Your 120V AC to 12V DC converter
and eventual central battery should be inside or conform.
I would let a local electrician or garden landscape contractor to install
it, since they know the local codes.