What am I doing wrong- can't get blade to light up? (pics)

[Matimeo]

Here are two pics of my first saber build, one in daylight in my living room and one in another room that is almost totally dark.

20131109_100912.jpg

20131109_100943.jpg

Background:
This is my first build.

Blade: 36" of 1"OD thick walled polycarbonate, sandedd on the outside, about 5 feet of clear cellophane gift wrap from Amazon (click to see link):

LED: 3W Green (sourced on ebay). 100 lumens at 900mah, 5 degree lens also sourced on ebay. With the blade out, it is plenty bright, too bright to look at.
Blade sits in the hilt 2".

I can't figure out why the blade isn't lighting up more than this. Seems like other posters have shown much fuller blades. I wondered if I put in too much cello wrap, but the blade is still way brighter at the bottom. I have a more than adequate reflective tip in there, so almost all the light is getting reflected back down. There isn't a noticeable difference in the fullness of the blade after inserting the wrap compared to when I lit it with just the sanded blade. Anybody have a guess as to what I'm doing wrong? Thanks for everyone's help! This site is the best.

[Matimeo]

Here's what the light pattern looks like with the blade off, with me standing about three feet from the wall. Does that look about right for a 5 degree lens? I got the blade a little brighter by finding the sweet spot with the film (not too much or too little), but it is still way less than what I expected. I guess I'm trying to figure out where the problem is or if I was just disillusioned about what the final product would look like.

20131109_114642.jpg

[Eco]

By your account, your blade should be just fine.
First step: Charge or change the batteries. If that doesn't fix it, double-check your power setup. You might be under driving the LED, as it should probably be way brighter than that.

[Matimeo]

Batteries are charged and fine. LED is being overdriven already- It is supposed to run at 750mah and I have it running at about 900 (the max it lists on the spec sheet). I've tinkered around with how much cello wrap I use and found that about 4 ft is the best compromise between getting a bright blade and not losing too much light. Here are some updated pics. Still seems quite dull to me, but this is my first build. Maybe people use camera tricks to get a brighter blade.

20131109_125250[1].jpg

20131109_130207.jpg

[Mandalorian]

That definitely looks better. But yes, cameras can do funky things to lightsabers. Most cameras just can't see that much range of light, so bright objects such as lightsabers appear to be much brighter than they are in real life.

[Sidd]

There are two things keeping your blade from lighting up better

first you are using too much cellophane wrap. drop it back to 3 feet tops

second you need the mirrored tip on there, it does help a lot trust me


Edit:

You posted while I did. glad you were able to get it to light up better

[Darth Xusia]

Ditch the Ebay bought led and get a P4 if it is just a stunt.
http://www.thecustomsabershop.com/Seoul-P4-P306.aspx

What is the led mounted to?

[Matimeo]

The LED came mounted to an aluminum star and I have that mounted inside a copper pipe cap as my heat sink.

So, on a related note: I experimented today by putting alkalines into my saber instead of the nimh rechargeables I was using. The LED is supposed to be driven at 3.2V, max 750ma. I have 4 x aaa nimh batteries with a 1.8ohm resistor, so I'm actually driving it at 889ma (900 is the listed maximum). With 6 volts instead of 4.8 with alkalines, I'm driving it considerable harder than that. Do you think I could keep driving it that hard and not ruin the LED?

[Jay-gon Jinn]

The difference in brightness you may be seeing in pictures compared to your in-person experience is due to the camera effect Mandalorian mentions, and also is likely in part to builders today commonly using a triple-led or quad-led of some type that will be significantly brighter than any of the single leds we used to use. I would take Xusia's advice and consider getting a Seoul p4 or the single Rebel from the store here, or possibly the GGW triple Rebel and using the two green Rebels on that led star.

As to the led you are currently using, the voltage isn't as much of a concern once you go over the vf of the led, it's current you need to worry about, and as long as you are under the rated maximum, it should be fine. Over-driving it may shorten it's lifetime, but when you look at how many hours an led is usually rated for, you probably wouldn't even notice the loss when you overdrive it. most led's are rated for 10's of thousands of hours, or several years, and overdriving them may shorten it by a few thousand hours.

As far as your blade goes, I usually use around 5 or 6 feet of gift wrap in my blades without any loss of brightness and have very full and evenly lit blades.

[Matimeo]

Much thanks to everyone who has helped with their input. Being new to working with electronics, it is for sure a learning process. I have one more thing that came to me today that might be behind my brightness issues. The way I have the batteries configured is that I zip tied two 2xaaa batter packs together, then twisted the wires together and soldered them to the rest of the circuit.

20131110_101746[1].jpg

However, I went out to the garage today and hooked up my voltage meter to the identical setup and this is what I saw:

20131110_101708[1].jpg

It would seem that wiring the batteries this way is actually only drawing current from one of the two packs? This is counter-intuitive to me, but I've never really fiddled with electronics before. I actually got the idea to do the batteries this way from someone who uses this site. Any ideas. If I'm only driving my LED with 2.6V, it's no wonder it seems dim.