I get allot of questions about this project. I made a list of most asked questions. I will answer more questions in time, and add them here.
how long will the battery last at full power?
At full power it will last 10 min. But you can also use it with only 100 leds. This way it will last much longer.
What kind of battery did you use?
I used a simple lead battery. 7 Ah 12v. This is not a verry powerful battery, but it hold it’s power verry well, even after months, it still works like it’s just charged. But cold temperatures have a noticable effect on lead battery’s.
Will you sell this “flashlight” Or build on demand?
The building process was verry intensive. This is a one time build. But I may going to sell lights in the future. I’m planning on making a new, even more extreme flashlight. And that kind will be less intensive to build. I’m not giving any details on this new build at this time. The plans are in progress. But it will be impressive for sure.
What kind of leds did you use
After some searching I found cheap led’s on e-bay. But be aware that specs are not correct. I bought 55.000+ mcd leds, but in fact, they were only 22.000 mcd. After some searching I found 5mm leds with 55.000 mcd didn’t even exist. I compared these 55.000+ mcd and they were brighter than my 20.000 mcd leds. And the e-bay seller did say they were 22.000 mcd after all. But the price was verry good compared to my local electronics store.
Resistors are using power to, is that a big loss?
I calculated that series of 3 led’s with a under full load droped voltage of the battery it consumes only a small amount of energy. In fact, the flashlight itself uses a total of 54 Watts. The resistors and relails only use about 4 Watts.
How much did this build cost?
It’s verry hard to say. I don’t see it as material cost, it’s the time you need to put in this kind of build, that’s what makes it worth allot more than only the building materials. But the material costs mostly did go to led’s. Around 100 bucks. And maybe 100 bucks for the rest of the build like battery, charger, cable, circuit components and plugs. I also bought some tools for this build, but those tools are always handy for future projects.