Lighting power and heat questions

[CodeMaster]

So I've reached a point in my Milennium Falcon build where I need to start the work on the electronics before I continue with the assembly.

For my lighting I'm looking at the following:

6 white LEDs 3.2 v forward voltage, 20 mA
19 white LEDs 3.4 v forward voltage, 30 mA
18 red LEDs 1.8 v forward voltage, 20mA
4 red LEDs 2.1v forward voltage, 20 mA
EL Sheets for cockpit interior and (hopefully) the Engines (no idea yet of the current draw for these, but can't be too high since they can run off AAA cells)

I'm going to be using 5V voltage regulators to reduce the voltage of the power supply.

I've used the led calculator resource provided by Grendels, and based on the calculations provided by that website, I will have a circuit with a total power disipation of 5,668.2 mW and a current draw of 1090 mA.

I'm going to be looking at a wall wart to drive this setup, and figure I will need a 5-12V supply with an output current of around 1.5A just to allow for "wiggle" room, as I need to determine what the current draw for the EL sheet circuit will be.

Does this sound reasonable for my power supply requirement, or should I be looking at more output current?

My other question has to do with the heat produced. 5.6W of power being dissipated by the resistors and LEDs seems like something I may need to be concerned with for an enclosed circuit within a plastic model, this is in addtion to any heat that will be generated by the EL sheet driver circuit (although that seems negligable on my bench).

Am I off my rocker for thinking I need to be concerned with the heat the lighting will produce?

Thanks in advance

 

[Grendels]

Heat is something I will be concerned with when I get to lighting up mine. Hopefully pretty soon! One thing that I have heard from more than one person who lights up their models. Anything with a lot of LED's is not left on for more than 15 minutes. Once you get yours done, I would turn it on and just check up on it ever few minutes checking for heat. Once it is warm to the touch, turn it off. You will then know how long you can leave it on.

I am going to use two LED light strips in mine and those put out quite a bit of heat. So I won't be able to leave mine on for long either....

 

[CodeMaster]

Thanks for the info.

I'm debating if I should try opening the engine vents and putting in a couple of small CPU fans to help pull the heat out. Of course that will introduce more issues like light bleed that I would have to see how to deal with.

I have a feeling that I may need to go with LED strips for my engines as well instead of the EL sheet, as I'm not sure the EL sheet will give me a realistic engine glow like I could get from LEDs. Of course that will affect the power requirements and heat.

 

[Grendels]

El sheets probably won't offer up enough light. So it is either a cold cathode or LED strips. A cold cathode will produce twice the heat of the LED strips.

I once saw a PC build into on of these models, it used the engine vents as cooling fans..... That is an idea!

 

[CodeMaster]

Thanks again for your input Grendels. I was thinking of a similar pc case. I think you're right about the light output from the el sheet. I'll have to order some led strips for the engines. Do you know the color wavelength of the blue strips ModelManTom sells?

 

[Grendels]

I am not sure of the exact wavelength, but I bet Tom knows, just send him an email.

 

[ModelMan]

Sorry I only just saw this!

The EL is definitely too weak for the engines. I tried that on my cutaway early on and EL just doesn't bring the power. And EL has a short 'half-life', the more you use it, the dimmer it gets. I then put CCFL in my Cut away engines and the inverters kept dying. I've had bad luck with inverters for some reason...

The LEDStrip is an ideal solution. Small, fast, easy, bright, simple, reliable. I'm not jsut saying that cos I sell the stuff! I wouldn't stand by it if I didn't believe in the benefits.

I gotta admit, you've got me off guard on the wavelength for blue. I now carry three colors of white, Warm, Natural and Cool. Depending on the look you are going for from which movie, those are also options. The color temps on those, in the same order is 3k, 5k and 6k. The Cool definitely has a blue tinge to it.

But watching Empire or SW itself, you could almost go with a Warm and I think even the Natural would work. The Blue is always a solid choice. Without a spectroscope, I don't have any way to gauge the wavelength. I will send in a request to the factory and see if they've got some handy stats.