Large Scale Central

What to use to power LED`s

Electronics
#1

I have 2 USA coaches, they both had 2 flashlight bulbs in them, I added 2 - 3LED strips, and 2 LED`s for the lamps in the back. All wired together, my engine has battery power, but I cannot run through the board, what is a good power source with a on/off switch to turn on whenever I want. Would 2 AA batteries be enough or to much.

Tom H

#2
tom huisenga said:
I have 2 USA coaches, they both had 2 flashlight bulbs in them, I added 2 - 3LED strips, and 2 LED`s for the lamps in the back. All wired together, my engine has battery power, but I cannot run through the board, what is a good power source with a on/off switch to turn on whenever I want. Would 2 AA batteries be enough or to much.

Tom H


Tom - if the LEDs you are using are white the are likely to have a forward voltage (voltage required to light) in excess of 3 volts. Since your two AA cells will provide only 3 volts the brightness will be dismal.

You could use 3 AA cells (or AAA cells) with a small current limiting resistor (30 or 40 ohms) or you could use a 9 volt battery with a larger current limiting resistor (470 ohms)

Wire all of the LEDs in parallel. If any of the LEDs are colored (red / green) you will need larger current limiting resistors for them as their forward voltage is closer to 2 volts.

Have a look at the information here about using batteries in a similar setup

http://www.trainelectronics.com/LED_Articles_2007/LEDs_for_Coaches/index.htm

Note that this article describes using latching reed switches to turn the LEDs on and off.

dave

#3

Simple method I use = 2 x 3 led amber or white flexi strip lights powered by a rechargeable 9v battery and a switch protruding through the base (push on/push off. Quite bright. They can use up to 12v without resistors as resistors are on the strip. Use the surface mount flexi types (neater) not the original LED types.

edit: added 9v. sorry…left it out on original. Doh!

#4

thanks! I thought a 9 volt battery would be to much, I will use that, got most of the stuff for that application.

Tom

#5

You can pull power from the tracks via the trucks with a little work. I’ve done that on my Bachmann J&S coaches. One circuit in the combine will power three or four LEDs in each car. I’ve got five cars lit that way.

#6

P.S. I’ll be doing a pair of clinics on Saturday at the Sacramento Valley Garden Railway Society clinic/workshop meeting. If you’re in the area, drop me a line, and I’ll tell you where!