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Post by petehuse on Jan 21, 2013 15:26:30 GMT -8
Greetings folks, this is my first post!
I have an HO scale layout with a fair amount of lighted buildings, street lamps, etc, both in 1.5v and 12v flavors. The problem I have is powering all of this. I currently have a couple of the Minitronics 1.5v "wall warts", but they dont seem to power more than around 10 bulbs before they get too dim. For the 12v, I have a couple dedicated Tech II power packs strictly to run the lamps, and they tend to overheat and cycle when I run about 15 bulbs. I believe I am using mainly the minitronics grain of wheat bulbs.
So I have been shopping on Ebay for low voltage power supplies, and have on-order a used Cenco device that has a variable voltage output (0-12v), and up to 5 amps (about $80). Has anyone had good luck using these laboratory type devices for hobby use?
Thanks!
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Post by steveturner on Jan 21, 2013 18:42:18 GMT -8
No electrical guru but here are my thoughts. You need to know the voltage of bulbs thats a given.But you need to look at the MA rating of the bulbs and the MA rating of the walwart or power supply.Add up the total of the MA rating of the bulbs and that must not exceed the MA out put of the power supply. Now there are power supplies with the variable voltage out put 3 to 12 volts that are not all REGULATED supplies..................you need to look see.Regulated will be more money. A good source for lighting might be a used lap top or computer power supply which are REGULATED meaning a fixed 12 volts or what ever and have plenty of amps TO RUN LIGHTS.NON Regulated the power supply does not reach its power out put say 12 volts untile its at its maximum load..............so it in theory could read 15 volts. Selected 3 volts could be 5 volts and so on. The other thing and i am not up on is wireing lights in parrael or series i think........there are benefits of one over the other. I think one method keeps lighting a consistant brightness.Maybe someone can chime in on that.
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Post by Mark R. on Jan 21, 2013 19:05:56 GMT -8
Can't be much help for your 1.5 volt supplies, but for your twelve volt supply, check on ebay under laptop power supplies. You can pick up 12 volt / 6 amp supplies for well under $10 plus free shipping. These are great for powering accessories - I've used quite a few of them in projects.
Mark.
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cnw
New Member
Posts: 45
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Post by cnw on Jan 21, 2013 20:36:48 GMT -8
No but it sounds like a good idea. You don't mention the specific types of power packs you are using. I used a 12v power supply from Radio Shack and didn't have any problems running my 5x9 layout with it. I probably had about 150-200 lights, mostly LED's connected to it. I had all the protection and circuit breakers and it only popped once. There was a thunderstorm in the area when that happened so I just assumed it was that.
Please let us know how things turn out for you.
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Post by petehuse on Jan 28, 2013 15:59:52 GMT -8
 Ok here is how the low voltage power supply worked out. LESSON LEARNED coming!!!! So this is a 5 amp, 0-15v variable voltage unit, with one knob turning power on and increasing in voltage as the knob is turned. I tested one of my 1.5v (40mA) incandescent bulbs and it worked fine. So I connected my 40 or so bulbs and set it to about 1.5v, and the indicated current was about 1.2 amps. (It has separate volt and amp vumeters). Worked fine! Lots of reserver power for more bulbs. However, I have a toggle switch to cut the output current to my bulbs, an easy way to just turn on and off the lights. When I do this toggle, the power supply is still powered on, but now without a load increases to around 6v at the knob setting (with no current draw now). So then I toggle my lights back on, and WHAMMO, the 6v setting immediately burns out about 35 of the 40 bulbs on the circuit! Apparently the device takes time to balance out the load on the circuit at the setting I had, but unfortunately these 1.5v bulbs are too delicate to withstand that power surge. So crap I now have a big job to re-bulb many of my buildings. I was not happy to witness this. In the future, I will not use that toggle, I will just use the knob on the power supply to turn on/off the lights. I had mounted the power supply down below the control panel, hoping to keep it away from unauthorized fingers, and just use the toggle switch. Someone suggested I stick in a zener diode in the wire to the bulbs, but the voltage is so low and the amperage fairly high, I couldnt locate the proper diode easily.
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