Help with red lighting

[huckabuck]

Hello to all from the other side of the equator,
boy is it cold here!! and raining!!!:mad2:

i am in the process of building an eyepiece/accessory box. what i would like to do is install several red lights for illumination. however, the only thing i know about DC systems is how to wire a trailer. i feel i could build whatever i need, i just have zero education towards capacitors, resistors, and the like. also i would like to make several dew heaters.

a vehicle is not always an option so i'll need some portable power, the lighter the better.

as for the lights i would like to use as small a battery as possible. preferably one which is incorporated into the box itself. i have room for a nine volt (one of those bigger ones with the springy things on top) or smaller. would this be sufficiant? also a dimmer switch would be nice.

could this power source also be used to fuel dew heaters(eyepiece,telrad,mirror,ect. )? and what kind of life span could i expect?

thanks in advance for all advice.
Huckabuck

[erick]

For lighting, if you go with red LEDs, you won't need much battery power at all. Most red LEDS operate off 2.4-2.7 volts, even the very bright ones now available (about 20,000mcd brightness, if I recall rightly), and with a very low current consumption. Two rechargeable AA or AAA batteries give you around 2.4 volts. I made up a couple of redlight torches, following the description here:-

http://www.iceinspace.com.au/index.php?id=63,278,0,0,1,0

They use 6,000mcd LEDs. I used rechargeable AA batteries - NiCds or Lithium, I cannot remember - and thought I'd better check how long they last. Well I left those two torches on in my house for 20 hours before they started to dim!!

So using a red LED, you'll need batteries, battery holder, wire, switch and LED - nothing more sophisticated - arranging mounting it all will be the biggest problem.

I wouldn't worry about dimmers - just have several LEDs that you can switch on separately - all on for bright, only one on for low light??

[huckabuck]

thanks Erick that sounds simple enough even for me. i was thinking of mounting the head of a couple torches in some kind of housing. i'll work on it for awhile as spring is aways off here.

[acropolite]

Red leds are as cheap as chips, if you can do the maths, you need about 20mA for full illumination, or as a rough guide, use a series resistor value of around 600 ohms, in series, for a single led on a 12 volt source.