The cree bulbs arent china junk?..i know nothing bout leds..was looking for a cheap solution for a spot light....i might just tape a flashlight for now
Cree is a top leader. Often counterfeit. Like OSRAM.
Check out nitecore flashlights. They use cree bulbs. Solid company for flash lights
Check out nitecore flashlights. They use cree bulbs. Solid company for flash lights
The simple truth is most LEDs are rated for a few hundred to several hundred lumen. Regardless of whatever the people who sell the flashlights claim. I used this led because it is a true 100 watt LED rated at 8000 - 9000 lumens. One of my neighbors has one of those "tactical" flashlights. He said his is 11,000 lumens. This is a flashlight that probably runs off of one or two of the 3.7 volt batteries and has a battery life of an hour or two. You're not going to get 11,000 lumens from that. You need some serious wattage. My LED draws about 2.7 amps at 35 volts. My battery won't last long, and I can't use the light for very long without overheating the LED, even with my heatsink and the P3 props blasting air over it.. This is fine for the Drone because I'm only going to kick it on for 30-60 seconds or so at a time.
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I finally weighed my 100W light assy. and the 11.1v 2,200Mah battery I have been using. The light assembly weighs 183 grams and the battery weighs 185 grams. I knew what the battery would weigh because those specs are online but had no idea about the light bar. I put the battery at the front and the light bar at the back. The drone felt well balanced so I guess it really was. Still, adding ~370 grams to a Phantom 3 is a lot of weight to carry and it shows. The drone works harder to lift off and even hold altitude. The fact that my light bar blocks the VPS sensors probably is not helping much either. At least I know what it weighs now, after the diet I put it on from drilling holes in and cutting away extra bits of the plastic bracket and ditching the cooling fan since the prop wash will be blasting it with air.
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Have you thought of pulsing the leds around 10hz. The current draw would be much less and you could fly longer. Your cheap/light weight lm555 timer could trigger a transistor or mosfet for light action.
The LED runs off it's own battery. The short flight times are due to the extra weight and the motors running hard to keep it aloft. I am going to do a full run and see how drained the battery is with my friends intelligent battery charger. That will tell me how much smaller a battery I can use based on how much was drained in a regular flight. My biggest problem now is the shear weight of this whole thing.
P.S. Another light for the drone.
Now I added a Spinning Disco Light to my P3P
P.S. Another light for the drone.
Now I added a Spinning Disco Light to my P3P
Hi Jon,
Your 2200 mAh battery is definitely stressing. you say its drawing 2.7A @ 35V, as the battery itself is a 3 cell lipo (3.7v x 3= 11.1v) this means you are drawing 8.5A from the battery @ 11.1v. According to this calculator your battery will last 0.18 hours or 10.8 minutes. Check out the battery calculator link,,, its very handy. At any rate this kind of load will destroy your 2200 mAh battery in short time. I would suggest you go for a 14.8v (4 cell) battery with at least 4000 mAh capacity, with at least a 4C rating. The best vendor for batteries I've found so far is Hobbyking, I'll get you link in the next post.
http://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-battery-life
Your 2200 mAh battery is definitely stressing. you say its drawing 2.7A @ 35V, as the battery itself is a 3 cell lipo (3.7v x 3= 11.1v) this means you are drawing 8.5A from the battery @ 11.1v. According to this calculator your battery will last 0.18 hours or 10.8 minutes. Check out the battery calculator link,,, its very handy. At any rate this kind of load will destroy your 2200 mAh battery in short time. I would suggest you go for a 14.8v (4 cell) battery with at least 4000 mAh capacity, with at least a 4C rating. The best vendor for batteries I've found so far is Hobbyking, I'll get you link in the next post.
http://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-battery-life
I need to recheck the amperage with the 11.1v Turnigy battery. TI just realized that my findings were with a good sized 12 volt battery sitting on my workbench, but I know the amperage is high. I also agree that the drain rate is bad for this battery but if I used a battery like the one you described there would be no point. The Turnigy 14.8v 4,000Mah battery on HK weighs 452g. That would be too heavy to actually fly. But as I said, I use the battery in short bursts. Even then, I know this is not good for the battery. This is really a fun novelty item but battery weight will keep it from being a light I can used for even several minutes at a time. Even at the total weight of 370g for battery AND light bar I still land with a real hot flight battery which makes me nervous. With 452g + 183g (635g) I would probably have a hard time staying in the sky.
Yes I feel your pain and goals. As I commented in this other thread: Custom 80w LED light bar for Phantom 3
I detailed the build I did with my son, below is the weights and measures i'm working with. I'm putting out about 78 watts, 4.95A @ 14.8v.
{{My next build will be 16 LEDs similar to the ones below - Cree XLM-U2. Output will be near 10,500 lumen, (lumens per the spec sheet, not some BS from China) @ 9.8Amps / 14.8v = approx 145 watts.}}
Weights / measures / time : Current light kit
I detailed the build I did with my son, below is the weights and measures i'm working with. I'm putting out about 78 watts, 4.95A @ 14.8v.
{{My next build will be 16 LEDs similar to the ones below - Cree XLM-U2. Output will be near 10,500 lumen, (lumens per the spec sheet, not some BS from China) @ 9.8Amps / 14.8v = approx 145 watts.}}
Weights / measures / time : Current light kit
- Wgt = Setup (frame & battery) weighs 16oz with the 2150 mAh battery. The 16oz setup flies well. Will reduce your flight time by 20-30%
- Wgt = Setup (frame & battery) weighs 20oz with the 6000 mAh battery. The 20oz setup flies ok, but you can tell the drone is grunting a bit. Will reduce your flight time by 35-40%
- Pwr = Measured current draw is 5.0 amps @ 14.8 volts = 74 watts
- Pwr = Estimated Lumen output is 750lm x 8 led reflectors = 6000 lumens. ( note: even though sellers state these reflectors with LED will output 1000lm, this is B-Sh-t. You really need to check the manufactures data sheets to estimated true lumen output )
- The LED reflectors came with Cree XLM-T6 (pre-installed) that were likely knock-offs, half of them failed in the first hour of use. I replaced them all with authentic Cree XLM-T6.
I like where you are going with this. I have one of those CREE flashlights with the XLM-T6 LED bulbs and that thing is great. I am not sure of the specs of the U2. is it similar to the T6 or better? I think it is more efficient right? I am going to opt for lighter battery when possible. Even if the battery is dead in 15 minutes you can't fly for very long with a heavy battery anyway. I would just get two small batteries and swap them out. I am using the 11.1v battery because it was a leftover from another project I had that was laying around. I find that my flight battery is uncomfortably hot when I land. I worry that we will destroy these batteries or even worse blow an ESC if we overload our drones with too much weight. Since the ESC's are not going to easy to replace that has me concerned. How about you?
My flight batteries are always hot after a flight (I don't put any add on items onto my drone). This has been the case in both 5* temps at Lake Tahoe this past new years & 100* days here in Cali.
I can't seem to remember my password to log onto healthy drones.com but I think they are fairly consistent. Drone-fan will have more info as he has flights with/without a light bar attached and can check battery temp specs.
I can't seem to remember my password to log onto healthy drones.com but I think they are fairly consistent. Drone-fan will have more info as he has flights with/without a light bar attached and can check battery temp specs.
My batteries have always been very warm after flying. The issue is that my battery was very hot to even hold in your hand after flying with a heavy load on it.
Check the Cree web site links below for specs. I usually use the "T-6" & "U2" models.
Also I added the snapshot below, this is where you can really see that if you are not fully powering the LED you only get a portion of the claimed '1000' lumens.
Cree XLamp XM-L LEDs
http://www.cree.com/~/media/Files/C...d-Modules/XLamp/Data-and-Binning/XLampXML.pdf
Also I added the snapshot below, this is where you can really see that if you are not fully powering the LED you only get a portion of the claimed '1000' lumens.
Cree XLamp XM-L LEDs
http://www.cree.com/~/media/Files/C...d-Modules/XLamp/Data-and-Binning/XLampXML.pdf
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