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How many amps should a wall wart be?

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  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Friday, March 18, 2011 4:07 PM

 Usually a wall wart supply won't be over 1, maybe 1.5 amps. There are exeptions. Much SMALLER is more common.

 For slightly more power in a single supply, it's easy to find replacement supplies for laptops and LCD monitors on eBay, for $6  I got a 14V 3.5 amp power supply meant for some brand of LCD. This isn;t a wall wart type, it's a small brick with a short AC cord.

                            --Randy

 

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May 2008
  • 4,612 posts
Posted by Hamltnblue on Friday, March 18, 2011 3:20 PM

Also you should never run a power supply at it's max rating. A good rule of thumb is to leave about 20%

Springfield PA

  • Member since
    February 2010
  • From: Hillsboro, Oregon
  • 934 posts
Posted by Eric97123 on Friday, March 18, 2011 2:49 PM

Thanks for the replies.. after I posed I thought it might be better to divide them up.. I have several extra warts floating around.

  • Member since
    February 2008
  • From: O'Fallon, MO
  • 292 posts
Posted by Lateral-G on Friday, March 18, 2011 1:51 PM

I did a search on grain of wheat bulbs and was able to find this:

 

http://www.hobbylinc.com/htm/cir/cir10101.htm

 

per the description they draw between 50-60mA @ 12V

 

1A=1000mA

1000mA/60mA= 16.6666

 

I would say you could safely light 16 bulbs with that 1A wallwart.

 

  • Member since
    July 2006
  • From: Pittsburgh, PA
  • 1,796 posts
Posted by JoeinPA on Friday, March 18, 2011 1:29 PM

Eric:

How many additional lights are you going to add?  You will need to figure the current draw and then get a wall wart that provides sufficient amps.  By the way, rather than trying to power them all from one source, it might be better to divide your lights up into groups and use more than one lower amp wall wart.  It will simplify trouble shooting later.

Joe

  • Member since
    February 2008
  • From: O'Fallon, MO
  • 292 posts
Posted by Lateral-G on Friday, March 18, 2011 1:24 PM

You have 1A of power available at 12V so using P=I*E the most you can safely use is 12W of lights.

Add up the wattage of each bulb you have and you'll know how many more you can add until you get to 12W.

I don't know how much wattage each of those bulb are, however. Hopefully someone may know.

 

 

 

 

  • Member since
    February 2010
  • From: Hillsboro, Oregon
  • 934 posts
How many amps should a wall wart be?
Posted by Eric97123 on Friday, March 18, 2011 12:18 PM

I have wired about a half dozen of the Model Power self sticking lights (12V) for my buildings and run it off a 1 amp plug that used to run my wireless router at home.  It lights up the buildings well but I want to add more and I know as I add more the lights will drop in brightness.  What is the recommended amps I should look for in the future?

 

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