36 Volt - 900 Lumen LED Stadium Lights

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Introduction: 36 Volt - 900 Lumen LED Stadium Lights

Light Up the Night! Contest

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Light Up the Night! Contest

The end of daylight savings and no lights meant that 5:30 pm soccer practice would be totally dark. With field space severely limited this meant the end of practices.  Next year we will be ready with portable battery powered field lighting, thanks to low cost, high power LEDs and lightweight long lasting lithium 36 volt battery packs from Dewalt.

I built two stadium lights. Placed on opposite sides of the field they do a nice job of lighting a decent size practice area for 10-12 kids. For a larger field or different sport, you may need several more. Each light draws ~.750 Amps, the Dewalt pack is good for 2.3 Amphours or not quite 3 hours. Still more than long enough for practice. 

Needed  36 Volt Dewalt Lithium battery pack
These things are great, lightweight, fast charging,  and very convenient after you have followed the directions to add standard power out wires. I will not detail how to disassemble the battery as this is readily available on the internet in several places.
http://www.slkelectronics.com/DeWalt/packs.htm
http://www.youtube.com/watch?v=qQJUEeKo7KQ
9 STAR LEDs (3 watts ~100 lumen each now available direct from China for around $2 per LED, ebay and other sources)
Most  of these high power, high efficiency LEDs operate from 3.5 to 4.0 Volts.  To save money we are not going to use the recommended constant current driver, but wire directly in series. (36 V / 9 LEDs) = 4.0 volts per LED.
CPU style heat sink
1 ohm, 10 watt resister (to add some safety margin)
18 inch long piece of aluminum angle (1/16" by 1 inch)
JB Weld Epoxy
1 inch hose clamp
10' x 1/2 pole (PVC pipe)
Screws, wire, solder








Step 1: Solder Leads to the Star LEDs

STAR LEDs are very nice to solder. They have wide solder pads, clearly marked + and -.  Start with the plus side and solder one lead to one + pad.

Step 2: Continue Soldering All 9 LEDs and 1 Ohm Resister in Series

Solder your leds into a series circuit.  The first wire goes to the + pad on the first LED.  Solder the second wire to the - pad of the first LED and solder this same wire to the + pad of the second LED. The next wire goes from the - pad to the + pad of the third LED. Continue until all 9 LEDs are soldered in the string you see below.  Next solder one terminal of the 1 ohm resister to the last wire and solder two 10' lead (+ and -) wires to the ends.

Step 3: Epoxy the STAR LEDs to the 18 Inch Aluminum Angle

3 watt LEDS at full power may generate enough heat to eventually destroy themselves unless applied to a heat sink.  You could buy special thermal epoxy but JB Weld brand epoxy appears to have enough metal to bond the LEDs and work as  transfer heat. Bond all your LEDs to the aluminum and clamp firmly in place for several hours.

Step 4: Add Heat Sink, Hose Clamp and Test Your Lights

With the LEDs on the aluminum angle will become quite warm.  Adding a heat sink (from a CPU cooler) is a good idea to maintain efficiency and LED life.  Bolt on a hose clamp for mounting your lights to a tall pole. Plug in and test your lights.

Step 5: Light Up the Night.

Mount the LED to a pole. I have used 10 foot conduit but the LEDs are light enough that PVC pipe works well too. Light up the night and enjoy.

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21 Comments

Thanks for the great DIY. I have been looking for something like this for wiffle balls in the yard. I have a few questions though. 1. What kind of LED's would you reccomend going with now with the advances in LED technology? 2. Do you think I could get these LEDs in 110v so I can use them on house voltage? The reason I would like to do this is so that I can get the light directed down onto the field from higher than just a normal halogen work light stand. Any ball hit high at all gets lost in the sky because there is no light up there. Also, I think I can get a brighter light and a more efficient fixture with LEDs opposed to the halogens. Thanks for your time.

Hi Sbauer9,

Wow, I had not thought about this hack in several years. Well done, you found a moldy oldie here. And you absolutely nailed the right question here, LED technology have advanced tremendously. Much simpler and easier to do now. Here is how I would solve a similar problem in 2016.

1)Yes, absolutely if you have access to 110 volt AC power, plug in with a set of outdoor extension cords.

2)These clamp type plugin fixtures are a simple and low cost approach. Can you get high enough by mounting to a ladder leaning on your house, make some tall poles or maybe a have a tree you can throw a rope over clamp on to the rope? Just be safe out there.

https://www.amazon.com/Bayco-SL-302B3-Brooder-Porc...

3) It's now pretty hard to beat the quality and price of standard screw in LED bulbs, especially from places like Home Depot and Amazon. High efficiency, robust to damage, and fairly inexpensive.

Something like these?

https://www.amazon.com/Philips-455717-Equivalent-Daylight-4-Pack/dp/B00YEMKJE2/ref=sr_1_4?ie=UTF8&qid=1477454241&sr=8-4&keywords=led+bulbs+100+watt

Thanks for the help and quick reply despite the age of this thread. I'll take a look into those. Oh, I'd like to compliment something in your design that I do not think a lot of people caught. I think it is a great idea on how you put the aluminum angle. I see that this forced all the light from the LEDs down onto the field. This won't be a problem with clamp on lights, but without that design, you would lose light upward. Great job and thanks for all your help.

but if I wasn't going to go with the clamp on lights, and I would opt to use something like the 3 star LEDs, what would you reccomend there that double be wired to 110v? Thanks

Sorry to bother you so much but I appreciate all your time and effort. Similar to in LEDs, there have been huge advancements in batteries too. I have an application similar to yours at a local youth football league that could use something. What kind of battery would you reccomend today, and would it be any cheaper that the $150 drill battery? Thanks again for your time, it will be put to good use!

Hi Sbauer9,

Another great question. Batteries have come quite a ways too, just not nearly as fast as LEDs. Hopefully in the next couple of years with more electric car companies, electric bikes, the Tesla battery factory and other manufacturers coming on line, lithium battery prices will start to drop soon. One online supplier (and a whole lot easier to use) is the 12 Volt Battery Tender -

https://www.amazon.com/Lithium-Phosphate-240CCA-Re...

https://www.amazon.com/Battery-Tender-022-0198LI-P...

And with a 12 volt battery you could either use just 4 STAR LEDs in series or and this is much easier (but does lose efficiency as converting twice) plug the batter into a 12 volt DC to 110 volt AC inverter and then power standard commercial 110 volt LED bulbs.

https://www.amazon.com/Power-Bright-PW400-12-Inverter-Watt/dp/B000OOZY5S/ref=sr_1_1?s=hi&ie=UTF8&qid=1477537861&sr=1-1&keywords=power+inverter+12+volt+dc+to+110+volt+ac

What do you mean by 4 Star LEDs? Thanks

HI Sbauer9,

Sorry, for the short cut. The more standard name to search for is "quad LED emitter". As I'm sure you are aware, each standard high power power LED emitters need to be driven by a voltage source fairly close to 3 Volts. So in LEDs wired in series, each LED drops the voltage by around 3 Volts. (My original instructable, I wired the LEDs in series (and when I accounted for the not quite 36 volts the Dewalt battery delivered plus losses and found it worked best for qty 9 LEDs wired in this series arrangement).

And.... these days the LED manufactures will do the series wiring for you. This is the quad LED star. 4 LEDs on one STAR, and instead of driving them at 3 volts. Below is one example of a quad star LED emitter. The specification says to use 11.6 to 13 volts. (Or a fairly typical 12 volt battery)

http://www.luxeonstar.com/cool-white-5650K-sinkpad...

I think I'm going to avoid the quad star because of the high price. As you can probably see, I'm trying to work around a fairly tight budget for each pole. Thanks for the idea though. I've got a plan laid out and it would be great if you gave me your opinion on it. I would use these as my LEDs http://m.ebay.com/itm/5-x-LED-3-Watt-Cool-Clear-White-Star-Bright-Wide-Angle-High-Power-LEDs-3w-w-/151187143805?_trkparms=aid%253D222007%2526algo%253DSIC.MBE%2526ao%253D1%2526asc%253D20150519202348%2526meid%253D85ccf6e45d4e43f3bf736958eef57af6%2526pid%253D100408%2526rk%253D5%2526rkt%253D25%2526sd%253D151171352633&_trksid=p2056116.c100408.m2460 and I'd use 7 of them. The reason for this so that I can get each LED to plus or minus 3.4v which is right in the middle of their reccomended voltage. Like I said before, I'd power them with a modified 24 volt drill battery. At this set up would you still go with a 1 ohm 10 watt resister? It's been a while since I've done a project where I've had to calculate the resistance needed, so I'd appreciate it if you could help. Thanks again for everything

Maybe these? https://www.amazon.com/gp/aw/d/B00ZWOYV7C/ref=mp_s_a_1_3?ie=UTF8&qid=1477621172&sr=8-3&refinements=p_85%3A2470955011&rps=1&pi=AC_SX236_SY340_QL65&keywords=3w+led+emitter&dpPl=1&dpID=41mYat3sEBL&ref=plSrch