Separate 12V power supply for layout lighting

[Anonymous]

Does anyone know of a separate 12V power supply that will allow wiring layout lighting without tapping into the DC posts on transformers?

I have well over 150 individual lights on my 14'x14' layout (I go for realism). I'd like to find a commercial unit that plugs in to 110V, then allows lead(s) to switch banks which in turn can operate specified sections of the layout lights.

Would appreciate any sources. Not sure what each little lights draw, but Radio shack and Wal-mart sources aren't adequate. Thanks. -- "johnniejack"

[nfmisso]

Hi Johnnie;

If your bulbs are like these: http://www.walthers.com/exec/productinfo/723-108; they are around 80 mA, Grain of Wheat (aka GOW) bulbs on ~12V will draw about the same, and around 100 mA on 16V. So lets assume 100 mA bulbs, and 200 of them; that is 20 amps.

Three of these would do: http://www.allelectronics.com/cgi-bin/category.cgi?category=480&item=PS-511&type=store.

Or nine ACTX-1124 http://www.allelectronics.com/matrix/AC_Wall_Transformers.html.

Or two of these:http://www.allelectronics.com/cgi-bin/category.cgi?category=480&item=PS-525&type=store. or http://www.allelectronics.com/cgi-bin/category.cgi?category=480&item=PS-527&type=store

Or one of these: http://www.allelectronics.com/cgi-bin/category.cgi?category=480&item=PS-2512&type=store

Personally, I would go the nine ACTX-1124, because feeding 20 amps through wires will lead to rather extreme heating, and voltage loss. You need 10 guage cables to handle it safely. It is easy to put a toggle switch in line with each supply:
http://www.allelectronics.com/cgi-bin/category.cgi?category=700275&item=MTS-85PC&type=store The problem with using a single high current supply is that you have to put huge cable everywhere, or you have a fire hazzard.

I am an Engineer, I am qualified to make the above suggestion.

Where in Wyoming are you? I live in Riverton for 1½ years about 8 years ago. I miss WY.

[cacole]

A computer power supply would be your best bet. Nearly all computer power supplies output +5 and +12 volts. You should be able to find a 200 to 250 Watt power supply for less than $100 from someone like All Electronics.

[Anonymous]

QUOTE: A computer power supply would be your best bet. Nearly all computer power supplies output +5 and +12 volts. You should be able to find a 200 to 250 Watt power supply for less than $100 from someone like All Electronics.

Yikes! I paid $20 US for a 300. The trouble with using a computer power supply is how would you turn it on?

The old fashioned ones, pre-pentium, had a switch, modern ones need a mother board.

[Hudsonmike]

Hi John;
I use a 110 inverter that puts out almost 19 volts ACDC and all my lights on my lay out
are controled by Autmotive head light switchs of which I have two mounted on my
codntrol board They work great they have built in reostats so I can dim the lights
half way and the lights will last longer .Got them from a Junk Yard.
Or better yet why don't you go on E-Bay and buy used lionel transformers

[Anonymous]

Actually, the new computer power supplies can operate without a motherboard if you use a jumper cable to close the circuit. (They just look at the pins on the motherboard so the computer can be the "switch.:") So you can actually wire a switch into the jumper and turn the power supply off.

You can find computer power supplies used (there are companies that harvest computers and sell those working components.)

http://www.comp-recycle.com/
http://www.lanyoncomputers.com.au/home/index.jsp

[Anonymous]

What aout using12-16V doorbell transformers?They install on a 4" square box, 11oV primary, 12-16V secondary(depending on the transformer) could be switched with toggle switch or rheostat. I believe this would be much cheaper than acomputer power supply. Really could be used to power any accessory on a layout.

[nfmisso]

QUOTE: Originally posted by coggins4

What aout using12-16V doorbell transformers?They install on a 4" square box, 11oV primary, 12-16V secondary(depending on the transformer) could be switched with toggle switch or rheostat. I believe this would be much cheaper than acomputer power supply. Really could be used to power any accessory on a layout.

These transformers are very low current - a door bell is a very low draw device, and intermittent too. These are not suitable for continuous duty, nor the kind of power Jack is looking for.

[nfmisso]

QUOTE: Originally posted by cacole

A computer power supply would be your best bet. Nearly all computer power supplies output +5 and +12 volts. You should be able to find a 200 to 250 Watt power supply for less than $100 from someone like All Electronics.

This one that I suggested is a 222 W computer supply: http://www.allelectronics.com/cgi-bin/category.cgi?category=480&item=PS-511&type=store He need tree of them for the lamps he has. They are $10.00 each.

[Anonymous]

A catch-up thank you to all who have responded. I've gotten some very good info - so much so that I plan to create a separate 12V system apart from powerpacks to control my table lighting. (Special acknowledgement to "nfmisso", formerly from Wyoming also.) -- "johnniejack"

[SteelMonsters]

QUOTE: Originally posted by LightBender


Yikes! I paid $20 US for a 300. The trouble with using a computer power supply is how would you turn it on?

The old fashioned ones, pre-pentium, had a switch, modern ones need a mother board.

The motherboard grounds the PS-on. In other words the black wire (ground) is connected to the PS-on wire Green). I do the same exact thing with a key switch. All you really need is a SPST switch. If one of the 5 voltages becomes shorted to ground, then the power supply shuts off. Reseting is as simple as opening and then grounding the PS-on wire. I like it because it's low cost regulated DC voltage.

nfmisso statement is correct. the wiring needs to be able to handle the current or it's a fire hazard. This can be done with heavy gauge wire, or spilt the current over several wires. It all depends on the load. A 12 watt light bulb on 12 volts draws 1 amp. lights add up fast.. You can safely put over 100 tortiouses on a 18 AWG bus. Add up the amount of current that all of the devices draws. (you can find that out by running a single light, motor, ect in series with a multimeter set to amps) I have a cheap multimeter for $20 that works nicely for what I use it for. You can test this out by putting as many lights as you think you can onto a single bus and put power to it. If the wires warm up or melt, take power off and try again with less load. Give yourself more than enough headway from overloading the wires. It's better to spend the extra $10, $20, or $30 depending on your layout size, going overboard gauge or # of wires than to start a fire and do much more damage. When in doubt, try it out.

[Anonymous]

Nfmisso, you are correct. I was thinking about a year ago that they would be a good, cheap source of power for switch machines. Momentary use to move the switch. I wasn't thinking when I suggested them for lighting.[B)]
[banghead]
Jeff Coggins