Introduction: Everlasting Solar Camping Night Lite

http://www.ledlights.greenwatts.info/ This simple project converts two solar garden lites and some PVC thin walled central vacume pipe into a pocket sized LED solar powered lamp that can be used as a night/comfort light or reading lamp. The finished lamp is water proof, will float and will last virtually forever and cost under $10 to make.

The circuit uses two NiCd AA batteries in series which under-drives the LED array giving off enough lite to be usable but consuming very little power. The batteries will last for thousands of recharges, the LEDs are rated for over 100,000 hours and the solar cells last over 20 years.

Step 1: Materials and Components

Disasemble the solar garden lites we are going to use the solar cells, the NiCd AA baterries and one of the Schottky diodes that you will find on the little circuit board. The solar cells may be glued into place but you should be able to carefuly free them. We will also need some wire, a small resistor and 12" of central vacume pipe. For tools you will need a utility knife, 20watt soldering iron, and small screw driver. You will also need clear silicone, PVC cement and super glue. http://www.ledlights.greenwatts.info/

Step 2: Step 1

Cut two 150mm/ 6inch sections of the PVC pipe using a fine toothed saw then make a deep score along each length of pipe with a utility knife. If you compress the pipe the plastic will break at the score mark down the length of each pipe section. http://www.ledlights.greenwatts.info/

Step 3: STEP 2

Heat each section of pipe in an oven at about c/f - 125/225 degrees until the plastic becomes pliable. It will be fairly hot so gloves are recommended. Remove from the oven and press between two flat surfaces. If the plastic curls after pressing and cooling repeat the process. Be careful not to over heat the plastic. http://www.ledlights.greenwatts.info/

Step 4: STEP 3

Referring to the dimensions on the plans (goto http://ledlights.greenwatts.info/led_light_lamp_plans.htm for the Camp Lite plans) layout and cut all the required plastic pieces. The plastic is very easy to score and break to produce very accurate and strait edges. Use pliers to break away smaller peices.

Step 5: STEP 4

To make the cutouts for the solar cells we need to heat the plastic as in step 2. Use a sharp pencil to mark the cut outs which will be 48mm x 48mm spaced 5mm apart and 5mm from each edge. Heat the plastic and first cut each corner then using a strait edge cut out the two openings. You may have to reheat the plastic for each cut depending on how quick you are. When finished cutting reheat the plastic and press flat. The resulting frame should overlap each edge of the 50mm x 50mm solar cells by 1mm. An alternative method is to first cut the two openings in a larger piece of plastic then trim the outside to the final dimensions...

Step 6: STEP 5

Mark guide lines onto the bottom of the plastic frame and mount each solar cell using silicone. A good method is to align and tack the cell let it dry then finish applying the silicone and set aside to dry. When cured the silicone should provide a water tight seal.

Step 7: STEP 6

Layout and drill the holes for the twelve LEDs on the front panel piece. Following the dimensions on the plans. Center punch each hole with a punch or nail. First drill a small pilot hole at each punch mark then drill out to the final 5mm size. Also drill out two holes on each end of the 10mm overhangs.

Step 8: STEP 7

Drill a 5mm hole in the center of an end panel for the switch. Cement the 5mm spacers to the inside of the end panel then secure the switch with silicone and let dry. Do not cover the electrical contacts with silicone.

Step 9: STEP 8

Cement the rest of the spacers on all of the panels removing any globs of cement and also checking for a good bond when dried. Applied properly PVC cement melts the plastic and creates a very strong bond when cured.

Step 10: STEP 9

Assemble the two side, bottom and back panels using cement and let dry. Make sure the panels are square to each other by using a square wood block and a flat surface. Place the larger panel on the flat surface, apply cement to the smaller panel and place into position hold the smaller panel square against the wood block. PVC cement dries fairly quickly and will hold after about 60 seconds. Cement small spacers into each corner.

Step 11: STEP 10

Insert the 12 LEDs into the front panel paying attention to proper polarity. If the LEDs are new the leads should be cut to about 8mm and bent outward at the ends. Place a small dab of super glue around the base of each LED on the inner surface of the front panel.

Step 12: STEP 11

Solder the negative and positive leads to the LEDs. First cut the positive wire a few inches longer then the row of LEDs, strip the plastic off the wire and give the wire a quick sanding. Tin each positive LED lead and solder the positive lead wire to all of the positive LED leads.

Step 13: STEP 12

Make the negative lead wire twice as long as the row of LEDs and strip half of the plastic off of the wire. Lightly sand the bare wire, tin all of the negative LED leads and solder the negative lead wire to all of the LEDs.

Step 14: STEP 13

Trim the positive lead and solder the resistor into place, (I used four 10ohm 1/4 watt resistors in parallel to give me a 2.5ohm but I do not think the exact value is critical so anything from 2 to 6 ohms should do fine) connect a lead to the other side of the resistor. Solder a short lead and the Schottky diode onto one side of the switch making sure of the correct polarity. See picture. Make sure to place shrink tubing onto the leads to cover the connections.

Step 15: STEP 14

Cement the front panel assembly into place and add the small spacers to reinforce the corners.

Step 16: STEP 15

Using a 3" piece of bare 12 or 14 gauge copper wire we are going to attach the two NiCd batteries. First using a fine sandpaper clean off both the positive and negative battery contacts and clean the ends of the copper wire. Tin both the battery contacts and the wire ends as shown then bend the wire into a half circle and solder to the positive terminal of one battery and the negative terminal of the other. Let the solder harden and then twist the batteries into alignment.

Step 17: STEP 16

Seal all the seams between all the assembled panels of the bottom assembly using silicone. We want to create a water tight seal.

Step 18: STEP 17

Add a positive and negative lead to the two batteries as shown. Place the batteries into position and tack with silicone. Solder the positive battery lead to the center lead on the switch, solder the lead from the resistor to the last lead on the switch and protect all the connections with shrink tube.

Step 19: STEP 18

Cover the entire switch body with silicone and seal the back of each LED with silicone. Carefully seal the switch hole in the side panel from the outside with a light coat of silicone making sure the switch can still operate.

Step 20: STEP 19

Connect the two solar cells in series by soldering the negative lead of one cell to the positive lead of the other cell and protecting with shrink tube. Tape the wires to the back of the cells or tack them with silicone. Attach the positive lead of the two cells to the diode lead and protect with shrink tube. Connect the negative lead of the two solar cells to the negative lead of the batteries and the LEDs and protect with shrink tube.

Step 21: STEP 20

Before cementing and sealing the top panel into place we need to test the circuit. Use the switch to turn on the LEDs and leave them on until the batteries are drained. When the batteries are almost drained the LEDs will dim at this point set the switch to the solar charging position and expose the solar cells to direct sun light for a few hours. If everything is working OK the batteries should now be at least partially recharged and the LEDs will shine at their regular brightness.

Step 22: STEP 21

Place a bead of silicone along the top edge of the spacers on all four sides of the bottom assembly then carefully place the top frame with the solar cells into position. Gently and evenly press down on the edge of the top frame until seated. If the frame is not completely flat you can simply flip the whole assembly over and place some weight on it until the silicone cures.
Additional pictures (high res) available on http://www.greencamplite.info

Comments

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EdurusFas (author)2013-07-29

This is very professional looking. Great Job!

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Schmidty16 (author)2012-06-01

also could u use a lighter to melt it on like some tin to heat it up

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Schmidty16 (author)2012-06-01

love iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiit cant wait to make one its awsomeeeeeeeeeeeeeeeeeeeeeee plzzzzzzzzzz contact meeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

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helpmonkey (author)2010-02-27

more details are now on http://ledlights.greenwatts.info

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draghi (author)helpmonkey2010-06-25

All the links are still pointing to the down website an the last one hasn't changed. great instructable. only just read it not built yet so adding to list.

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-max- (author)2010-02-11

WOW now that's a LOT of steps.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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andybuda (author)2010-02-11

hi very good instructable top mark
never thought to use pvc pipe like this even though you can make beer mats out of yogurt pots in the same way and plant pots out of old vinyl
im going to have a go at making something like this but to power some leds on a photo switch and charge batteries by solar iv not had much look with the led though cant get the right power to them they work fine with 2 aa batteries but wont seem to work in parallel(just 1 lights up)

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mr. clean (author)2009-12-05

this is a great instrutable i love my light and something you can do instead of cutting squares out for the solar pannels is drill holes for the leads to run through and silicone the pannels right to the top of the box. one thing i can't figure out though is why there are allways 2 or 3 LEDs that dont light up can anyone help.

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helpmonkey (author)mr. clean2009-12-08

...also do you have any pics of your lamp would love to see them?

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mr. clean (author)helpmonkey2009-12-08

heres some pics, and the all the LEDs light up but some not as bright or very dim as u can see in the pic. if i do need a higer forward voltage how do i achieve that? In the third picture of the switch i used a mini toggle from allelectronics.com and over the switch is a piece of plastic tubing fitted over the switch and siliconed, the other end is simply melted shut.

solar light 002.jpgsolar light 006.jpgsolar light.jpg
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helpmonkey (author)mr. clean2009-12-09

Hey great pics and good job mr clean! the only solution is to replace the LEDs that dont light up as increasing the voltage can only be done by adding more batteries which complicates the solar panel etc... At my local dollar store they have 24 LED night lite fro$2 ... pretty cheap ... also I am working on a new light that will use a joule thief circuit ... the advantage is the LEDs can be over driven without damaging them with heat ... I will be posting plans on my website greenwatts.info

Wayne

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mr. clean (author)helpmonkey2009-12-09

i noticed a small problem when ever i try to go to greencamplite.info it comes up with a completely different page, just thought id point that out. and as for the new light ur building i can't wait to see it! :)

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helpmonkey (author)mr. clean2009-12-08

you either have a couple of bad leds or possibly some leds that require a higher forward voltage to turn on ...

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VadimS (author)2009-07-24

NiMH batteries last about 50% longer and contane more energy but NiCds have a slightly higher efficiency, so NiMH would take longer to charge but the light would stay bright longer and the battery would last about 3 years (apposed to 2)

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ReCreate (author)2009-07-02

Why are the images soo tiny? it hurts my eyes looking at them...

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mattccc (author)2009-06-08

how long dous this last

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helpmonkey (author)mattccc2009-06-27

a long long time... it under drives the LEDs which increases thier life span ... which in turn is easy on the NiCd batteries increasing their life span and the solar cells will last 20 years or more

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CybergothiChe (author)2009-06-22

That's cool, G!

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FeedTheGrid (author)2009-04-24

Nice construction. I'd like to make one of these. Thanks.

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helpmonkey (author)2009-04-10

I have been using the light as a night light in my 5 year olds bedroom ... I let him operate it as it is completly safe ... and amazingly he is going to bed with much less fuss :o)

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Grumpy_Fish (author)2009-04-09

I'm definitely playing with PVC this weekend, but out of curiosity, wouldn't the switch present a possible failure point (especially by way of moisture infiltration)?

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helpmonkey (author)Grumpy_Fish2009-04-10

Its a push on push off and I placed a light coating of clear silicone around it so it should be good ... i could not locate a water proof switch :o( ...

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baken411 (author)2009-04-05

i never thought about melting a pvc pipe to get flat plastic, great instructable 5 stars

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RiddleOfSphinx (author)baken4112009-04-05

Yeah, I was wondering about how to go about doing that one day. Thanks for the tip. This would make a very good survival pack addition, too :)

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helpmonkey (author)baken4112009-04-05

yes the thin walled PVC is very nice to work with just make sure you dont overheat it ... you can also do the same thing with ABS palstic ... it is a little harder to work with but much stronger

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hominid (author)2009-04-04

Inspiring. I couldn't find the value of the small resistors. Do you mention that? Thanks Kind regards Hominid.

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sw (author)hominid2009-04-05

Since the LEDs are being driven at 1/10 of their power, and there is no chance of the Nicads putting out more energy, the resistors are not needed. All they do is WASTE electricity.

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helpmonkey (author)sw2009-04-05

yes I fully agree but I always use resistors with LEDs besides with this circuit they dont waste much

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helpmonkey (author)hominid2009-04-05

I used four 10 ohm 1/4 watt resistors in parallel which gives you 2.5 ohms...

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mchenson (author)2009-04-04

I like the idea of using the piping for a container! But I have a few comments. Connecting the positive of solar cell to the negative of the other is called SERIES. Parallel is when you have positve to positive & neg to neg. The output of the solar cells are 4v in bright sunlight, so an expensive Schottky diode is not called for. Any low power silicon diode would do. The difference is less than 1/2 a volt. You should draw a simple wiring chart so people know exactly where things go. Finally, the output of the Nicads are only 2.4 volts, which would make the LEDs, especially white ones very feeble. Find a way to get 3 nicads working and you will really go to town!

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helpmonkey (author)mchenson2009-04-05

thanks mchenson ... the parallel was a typo (ill fix it) ... the schottky diode came out of the solar garden lite so really didnt cost anything ... the wiring diagram is on www.greencamplite.info ... as for the batteries we want to underdrive the LEDs which gives us the very low power usage ... even at 1mA there is quite a bit of usable light for its intended purpose ... I will be designing a high power unit using emitters and 6 NiCds with fold out solar cells :o)