# building lights



## RCE (Sep 14, 2009)

The buildings I am building will use LEDs for light.
I found this while looking for a power supply for the lights.
https://www.trcelectronics.com/View/Mean-Well/RS-15-3.3.shtml


1 Will this work if I wire all the LEDs in parallel? 

2 How many can I use, with my bad math looks like up to 150 LEDs.
Thanks 

Richard


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## Treeman (Jan 6, 2008)

The problem you would have with this power supply is that you have no margin for voltage drop in your wiring. Most LEDs need 3.3 volts to light fully. Any wiring will have resistance dropping the voltage to the load. It would be better to start with a higher voltage, then use a current limiting resistor at each LED. 12 volts would be better.


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## Dan Pierce (Jan 2, 2008)

I would not use 3.3 volts for leds as many are less than 3.3 volts and if no current limiting resistor is used they can be blown. For a 12 volt source I would tie 3 in series and add a resistor for a 2.1 volt drop for 3.3 volt leds. This is less parts and when needing 3 or 6 leds in a building it makes for an easier install.


OR get a reel of 12 volt strip type leds with the resistors built in. I use these and really like them as I place 2 in series and run them from my 24 volt DCC track.


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## placitassteam (Jan 2, 2008)

Since I rarely run at night and don't have power to my layout, I didn't bother with a power supply. My buildings are lighted by LED Christmas lights. I cut them into 3 light strings and power them with a 9 volt battery. A battery can power 3 strings in parallel for at least several hours. I have run 1 string continuously for 2 days.


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## choochoowilly (Oct 31, 2016)

*solar LED's*



RCE said:


> The buildings I am building will use LEDs for light.
> I found this while looking for a power supply for the lights.
> https://www.trcelectronics.com/View/Mean-Well/RS-15-3.3.shtml
> 
> ...


 Richard I use $.98 solar pathway lights from Wal-Mart, you can add a extra led if needed and it does dim it about 10% but it adds 25% more on time, sometimes I take the apart and cut in the solar panel and others I just cut a 1/3/4" hole and silicone it in, Bill


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## choochoowilly (Oct 31, 2016)




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## choochoowilly (Oct 31, 2016)




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## choochoowilly (Oct 31, 2016)




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## choochoowilly (Oct 31, 2016)




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## Paulus (May 31, 2008)

I like that last idea of using those cheap solarlights in buildings. Looks good and that way you can easily replace the building. I guess you can also place the collector loose from the object if you don't want to integrate it or when it is not possible to integrate (like for instance in a car or pole lanterns).


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## RCE (Sep 14, 2009)

choochoowilly How long do the solar lights last? What is the life of the batteries, and the life if the solar panels? how often do you have to replace the fixture? Where do you find extra 1.2v LEDS from other solar lights?
Thanks

Richard


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## choochoowilly (Oct 31, 2016)

Richard, not sure how long they last but will check and get back with you, I'm thinking about 3 to 4 hours, I've had 2 buildings out side for about a year now and the batteries are still working, solar panels the same and haven't had to replace anything. Had a bad circuit in one of the solar/charging units, probably my fault from soldering so I replaced the charging circuit with a new one ($.98) and it worked fine was left with new LED, and battery. Think I've been using 2.2vdc LED's but will check tonight with a 3vdc one and see if it lights. Saw on this same thread were one put the solar panel in a window. I have found the panel doesn't need to be in direct sun light and will charge inside if house lights are on, Bill


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## RCE (Sep 14, 2009)

I found this online at Walmart.
https://www.walmart.com/ip/Westingh...647-967c-12e26aabc4b1&adpgm=wpa&pltfm=desktop
It looks like the LEDs are wired in parallel. I could add wire between the lights and use what I need now and add more up to 100.
What do you think yes, no, maybe,or use single solar lights and modify them?


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## Scott (Jan 29, 2008)

Pretty neat stuff


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## choochoowilly (Oct 31, 2016)

Well I tested the voltage needed to power different led's and found if it is powered by a 1.2vdc battery then that's the biggest led you can use. After further study I believe the buildings where I taped into the existing LED that those Led's came from the solar lights that I had messed up the circuit board in and was left with, solar panel and battery. Did find them on eBay though. Time on the single bulb buildings lasted just over 3.25 hours and the dual bulb ones lasted about 4.5 hours. RCE I looked at your Wal-Mart Westinghouse led lights but the whole purpose of having separate ones is no wiring and with the Westinghouse one you get a lot of lights but a lot of wiring, Bill


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## RCE (Sep 14, 2009)

I don't mind the wiring part. I think I am going to try using a power supply from an old broken laptop and use these https://www.digikey.com/product-detail/en/microchip-technology/CL2N3-G/CL2N3-G-ND/4902353 to drop the current with white Christmas tree LEDs. After I get every thing working I'll buy a timer to turn the power supply on and off.I have low voltage wiring form the house to the layout already.Just need to wire between the buildings, my layout is small so there isn't much wiring to do.

Richard


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## Paulus (May 31, 2008)

Sounds good. Looking forward to see the results.


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## choochoowilly (Oct 31, 2016)

Up date to solar pathway lights. Found that the LED's are actually 2.5 to 3.3 VDC and even though there is only 1-1.2vdc battery there is 2.4 volts to the LED, the low voltage is boosted by a mini transformer call a joule thief or a converter what I thought was a resistor on the board was actually a converter. I was trying to get a 2.3 VDC red blinking light to work for the top of a water tower I'm building. Come to find out there is a small IC in the LED that makes it blink and the converter interfered with the IC causing it to light but not blink, so I removed the converter and jumped the circuit with a small piece of wire, replaced the single battery with dual AAA and put 2 solar panels in series with charged the two batteries supplying the necessary 2.4 volts to the LED and it now lights and blinks great lasts about 12 hours before I needs to be charged, Bill


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## Paulus (May 31, 2008)

Nice solution!


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## choochoowilly (Oct 31, 2016)

*solar lighting*



choochoowilly said:


> Up date to solar pathway lights. Found that the LED's are actually 2.5 to 3.3 VDC and even though there is only 1-1.2vdc battery there is 2.4 volts to the LED, the low voltage is boosted by a mini transformer call a joule thief or a converter what I thought was a resistor on the board was actually a converter. I was trying to get a 2.3 VDC red blinking light to work for the top of a water tower I'm building. Come to find out there is a small IC in the LED that makes it blink and the converter interfered with the IC causing it to light but not blink, so I removed the converter and jumped the circuit with a small piece of wire, replaced the single battery with dual AAA and put 2 solar panels in series with charged the two batteries supplying the necessary 2.4 volts to the LED and it now lights and blinks great lasts about 12 hours before I needs to be charged, Bill


 Re tested after working on the water tower, lighting system has been idle for almost a month while I worked on the tower and found it work just fine, will be setting electronics into the tank of the tower and had located the solar pan







els in the cat walk area


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## choochoowilly (Oct 31, 2016)

Shot of my test buildings and lights on at night, all are lit with the cheap solar path way lights from Wal-Mart except for the switch tower which came with it's own light and solar panels. All 3 have been outside in the same location for all most a year now


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## Dick Friedman (Aug 19, 2008)

The problem is not voltage, exactly. LED's draw current until they blow up. One way of controlling this is to keep the voltage low. Another is to use a current limiting device. Then you can power your lights from any voltage from 3.0 to at least 18V. With a rectifier and a capacitor, you can even run them on AC and (onboard a train) the capacitor will keep the lights on even if the track is momentarily dirty. I believe the current limitere is a CL2. I found mine at Mouser.


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## Dan Pierce (Jan 2, 2008)

The cl2-n2 is a 20ma current limiter. Make sure you use 20ma leds with the device or wire 2 10ma leds in parallel. Of course you can use 20ma leds in series, and at 3 volts per led plus the cl2 drop be careful to not exceed the voltage of the power supply being used. So, a 9 volt battery can do 2 20ma leds in series with the cl2, and 3 if power is 12 volts.


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## Dick Friedman (Aug 19, 2008)

I've wired LEDs in parallel using the CL2, because I can power anywhere from 2 to 14 LEDs at one time using track power. My circit board simplifies this.


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