Large Scale Central

Lighting for structures?

General Discussion
#1

I’m thinking of using a Malibu brand, 12v DC system to power structure lights on my layout. If I do this, what kind of grain of wheat bulbs should I use? (I need bulbs that small for at least some applications.) Would a regular 12v-rated GOW bulb be ok, or would it burn out too quickly? It may be difficult to access or remove burned out bulbs, so I’d like to have them last as long as possible.

Any advice on this subject would be greatly appreciated. I’m not an electrician and know very little about it.

#2

Ray, Malibu is unregulated AC, not DC. Makes no difference to incandescent light bulbs though.

What does make a difference is the unregulated AC, and 16 volts is more common on the output. When lightly loaded the output can creep higher.

Many people use these for lighting, I’d buy one and a voltmeter and measure what you get as output.

18v incandescent bolbs would be a better choice and would give more of a yellow glow than a bright white light.

(and they would not burn out like 12v bulbs would)

Regards, Greg

#3

A good trick where lights are difficult to get at is to run bulbs at a lower voltage than their rated one . A 24 volt bulb will last forever on a 12 volt circuit , but will give out less light . I have run grain type bulbs designated 12 volts off a redundant train controller set at 8 volts . No blows .

Mike

#4

I really like the Malibu type garden lighting controllers. They are designed to operate outdoor lighting, have a variety of timers and detectors available, are low cost and are extremely reliable.

Another trick to use with the Malibu (or any other unregulated / transformer) type of supply is to run two, three or more bulbs in series. Using two 12v bulbs in series on a 16v supply effectively runs each bulb at ~8v. Using three in series puts each bulb voltage at a little over 5v. Other combinations are easily made dependent on the bulb voltage. Series groups can then be run in in parallel up to the rating of the controller.

Just putting 12v bulbs on a 12v circuit tends to produce a lot of very harsh light. The series arrangement tones down the amount and color of light produced and looks much more realistic in the garden. Try putting each series set in a single building or area.

The only downside is that it’s a little more difficult to locate a burned out bulb, but since the bulbs in series are running at very conservative voltage levels, they will have extremely long lives, so this really isn’t much of a problem.

Happy RRing,

Jerry

#5

Doh! I don’t know why I thought it was DC. Oh well, it still sounds like the best way to go, though I guess I wouldn’t be able to use LEDs in any of the structures if it’s AC power.

Now I just need to find grain of wheat bulbs that are rated higher than 12v.

#6

Aristocraft carries GOW’s but I’m not sure of the voltage rating.

Warren

#7

I got a bag of 14v GOW bulbs at a hobby shop a few years ago. They shine very nicely on the malibu transformer.

LED’s are possible. I used a diode bridge from RS to provide me DC for turnout motors and suchlike. Just remember that you’re running 12 to 18v and figure your LED circuits accordingly. I have some 3v yellow LED’s and run 2 of them in series from 4 AAA cells. 6 in series, or maybe 4 should work well from your malibu.

#8
Ray Dunakin said:
Doh! I don't know why I thought it was DC. Oh well, it still sounds like the best way to go, though I guess I wouldn't be able to use LEDs in any of the structures if it's AC power.

Now I just need to find grain of wheat bulbs that are rated higher than 12v.


Ray:

As I pointed out, you can use lower voltage rated lamps in a series arrangement. Start by putting a couple of your Malibu 4w or 6w lamps in series and see how they look in a building in the garden at night.

As to a small lamp source, look at Micro-Mark for both “Grain of Rice” and “Grain of Wheat” lamps.

The GoR lamps are 3/32" dia. x 3/16" long and rated at 12v, 30ma. Package of either 40 clear or 40 mixed colors (10 each clear, green, amber and red) is <$35 on sale or ~$40 regular price.

The GoW lamps are 1/8" dia. x 3/8" long and are rated at 12 to 14v, 75ma. Package of 100 clear or 100 mixed colors (25 each clear, green, amber, red) is <$35 on sale or ~$40 regular price.

Happy RRing,

Jerry

#9

Jerry , you are right , of course , no argument there . But we should not lose sight of using 12v GOW’S or whatever with 6 to 9 volts across them , easily obtained from an old HO controller we all have lying around . Or cheeep at a show . OK , use a 12v battery charger then .
The wiring of the bulbs for remotely sited bildings then becomes easier , a simple pair of wires going to the desired place . In the event of a bulb fail it at least shows up as one only , not one of three .
I also happen to have a load of war surplus 24v instrument panel bulbs which work well off 12-16v . I have not had one blow yet .

I suggested this in another place , and someone said it sounded as daft as putting a 10 amp fuse in a 5amp application to stop it blowing . Yes . Interesting point .