Running 12v DC equipment on 120v AC (indoors)

FireEMSPolice

Member
May 21, 2010
3,429
Ohio
My former boss is now a Criminal Justice instructor and wanted to wire up a lightbar in the classroom for effect during training. He isnt sure if he wants to go with a halogen or strobe bar.


What do I need to wire this up? Converter? Any recommendations?
 

Retired1

Member
Jun 1, 2010
1,912
Woodward County, OK
I have the identical* Astron RS-50A that Pimp has (shown again below). They are available on eBay (current offerings run $70 to $260, with $129.99 being a decent price for a new one).


Yes, you can run your leads from the power supply to a switch box and from there to multiple devices.


Terry


* = mine does not have the scratches and mine has a serial number <insert smilie here>.


PS - Also, be prepared. These babies are hefty! You will want to find a quasi-permanent place for it and then LEAVE IT THERE!

Pimp said:
You will need a 12V converter. This is a device with hot and ground leads for 12V and is power off a 120 plug inside your home.



You can buy one (if you love blowing money) at Radio Shack or you can look for a good one from Astron or Pyramid.






I have a RS-50A from Astron that I love.



ai93.photobucket.com_albums_l41_Pimpala03_DSC09648.jpg


ai93.photobucket.com_albums_l41_Pimpala03_DSC09643.jpg
 
Last edited by a moderator:
May 22, 2010
787
Columbiana County, Ohio
Coreyhudson2 said:
It all depends on the rails of the specific power supply, the wattage is just the sum output of all the rails (+3.3, +5, +12, -12) together. Some 500w power supplys could have more ampacity on the 5v and less on the 12 eg (+5v at 5a/ +35 at 12v) whereas another 500w could have more on the +12 rail (+5v at 3a/+12v at 40a).

Basically don't go thinking that your 500w lightbar would be fine on a 500w power-supply. Most likely you will need a 650w or 700w to support your needs at 12v.


Also for all those wanting to get thier power supply working whenever its plugged into the wall, all you have to do is ground off the Purple wire. (Purple to black)

Correction... Connect the PC's power supply's Green wire to any Black wire on the 20 / 24 plug
 

harwood39

Member
May 26, 2010
142
Fargo, ND
I have had good luck running lights off of a CPU power supply. I run LEDs tho so they dont draw a lot of amps. Here is basically what I went off of but not to the extreme they did. I just linked the Green/Ground, and used the cables coming off the supply instead of adding the binding posts. It may not be as clean as the write up, but it gets the job done and it is hidden anyways. The next couple I build will be basically his set up with binding posts but I will only have one for 12V and ground. Oh, and in place of a resistor you can use a 3357 or 1157 bulb. They draw the same load with both filaments lit up as the resistor does. I used the bulb idea.


http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply


Here is the basic set up of what I run currently off one supply, there will be a second mini bar added, and a few more heads. It can definitely handle the load without a problem and stays very cool running all day long. I am running an SVP 20" Aerostar 8 Head M-Tech Bar, LED HAW's, 2 Sound-Off LED3's, and 2 Whelen OS Lights.


ai1238.photobucket.com_albums_ff493_hardevelopment_Other_20misc_100MEDIA95IMAG0038.jpg
 
Last edited by a moderator:

911psl

Member
Jan 23, 2011
88
CT/USA
Well, I went with the computer power supply idea. Picked up a few binding posts from Radio Shack. I threw it all together, and it success! I will try to get a picture up here for it. I only did 12V rather than 12 and 5.5 volt like the tutorials online suggested. The best part--I didn't electrocute myself :thumbsup:
 

Newberry13

Member
May 21, 2010
613
SC, USA
Yup, RV converters work wonders! Mine is an 80 amp supply. The best part? I got it for free!
 

emtanderson51

Member
Apr 9, 2011
3,795
USA Massachusetts
Stendec said:
Be advised, with everything on, that thing will draw huge amps. Someone else can do the math, but even with the rear flashers off, I think it will draw considerably more than the average Radio shack inverter can handle - you'll need to spend larger bucks for a big unit.

You definitely do not want an overheating power supply in your kid's room.


But, if it's in good shape, and all the lamps and motors function, unless her room is the size of the Superdome, the novelty will wear off in about 5 seconds, after her stuffed animals explode into flames and her fishtank boils. Those things put out serious light with clean domes and fresh bulbs.

:hahano: rofl @ the stuffed animals and fishtank comment
 

wfd67

Member
May 25, 2010
207
San Francisco area, CA
emtanderson51 said:
How many lightbars could you power with that thing?? Seriously. Like 2 edge bars or an edge and loaded MX. Just curious

About that, yes; the MX7000 bars I have on the bench (going to or from fire rigs) draw 25-55a each, depending on configs, typically around 45amps all light up on the MX7000 (but we do enjoy our rotators).


I use a 25 amp on the bench for testing, and can't usually run the thing at full speed with every function on. The older JetStream ran fine on the 25 amp, but not too many other bars can I claim the same, thus I'll testify 25 amps ain't enough most days...
 

toon80

Member
May 24, 2010
2,487
Laval, Canada
harwood39 said:
I have had good luck running lights off of a CPU power supply. I run LEDs tho so they dont draw a lot of amps. Here is basically what I went off of but not to the extreme they did. I just linked the Green/Ground, and used the cables coming off the supply instead of adding the binding posts. It may not be as clean as the write up, but it gets the job done and it is hidden anyways. The next couple I build will be basically his set up with binding posts but I will only have one for 12V and ground. Oh, and in place of a resistor you can use a 3357 or 1157 bulb. They draw the same load with both filaments lit up as the resistor does. I used the bulb idea.
How to Convert a Computer ATX Power Supply to a Lab Power Supply - wikiHow


Here is the basic set up of what I run currently off one supply, there will be a second mini bar added, and a few more heads. It can definitely handle the load without a problem and stays very cool running all day long. I am running an SVP 20" Aerostar 8 Head M-Tech Bar, LED HAW's, 2 Sound-Off LED3's, and 2 Whelen OS Lights.

Just tried it with an ATX, 420 watts, PC power supply. I did all the voltage terminals and so far it works great. Fun little project to build while watching a play-off game.


I don't have LEDs. I tested a mini Code 3 XL sealed beams on it and so far so good.


According to the specs on the side of the power supply, the 12 Volts rail gives me approximately 22 amps. Not bad for a free PSU harvested from my old college computer.


Now does anybody know if you can put a few in parallel to crank up the amps? I don't see why not but maybe someone knows better.
 

shues

Lifetime VIP Donor
May 21, 2010
10,269
NW Indiana
toon80 said:
Now does anybody know if you can put a few in parallel to crank up the amps? I don't see why not but maybe someone knows better.

I remember this working great using three or four AT power supplies. ATX power supplies have more protection built in, so you might have trouble with the power supplies "sensing" one another.
 

toon80

Member
May 24, 2010
2,487
Laval, Canada
Yeah. I've read something about this issue on different forums. They were talking about using diodes to create a non-return/no-feedback system.


Problem was possible heat production in the diodes...
 

ResponderPSE

Member
May 28, 2010
143
Saint Louis
We offer power converters that go up to 80amps. They simply plug into a 20a power receptacle and delivers well regulated DC current, up to 80amps for under $225. It may be pricey for home use, but it's a steal for anyone needing 12VDC power for an equipment show room. I have three in house that I use. Contact me for details.


power-converter-80-amp.jpg
 

emtanderson51

Member
Apr 9, 2011
3,795
USA Massachusetts
I have a marine battery. I put the leads on the battery posts as to not have to keep attaching/detaching leads. I have a 2/10/50 amp automatic battery charger attached to the posts above the leads. This acts almost as an alternator. I ran 10g +/- wires to to ground blocks w/10 screw posts on ea. I simply run my lightbar cables to the blocks or the ground to the - block and the+ from the switches to the + block. TOTAL COST: $176. Bought everything at Walmart but the grounding blocks which I got at Home Depot. They are in the home electrical section with the fuse boxes. I can run 2 or 3 bars at a time....
 

fireball3

Member
Oct 25, 2010
864
Lyon, France
Steve, I am interested in your idea!, But why use the battery, plus charger?, Why not connect directly to the charger?.


I use a 20amp power supply 220volts/12volts, but it only supports one bar, barely!


Do you have a solution for high intensity!


Cyril
 

shues

Lifetime VIP Donor
May 21, 2010
10,269
NW Indiana
fireball3 said:
Do you have a solution for high intensity!

The battery you asked about is the solution for high 'intensity.' The charger can only supply so many amps, while the battery can supply a much higher number of amps.
 
May 24, 2010
1,627
PG County, MD
emtanderson51 said:
I have a marine battery. I put the leads on the battery posts as to not have to keep attaching/detaching leads. I have a 2/10/50 amp automatic battery charger attached to the posts above the leads. This acts almost as an alternator. I ran 10g +/- wires to to ground blocks w/10 screw posts on ea. I simply run my lightbar cables to the blocks or the ground to the - block and the+ from the switches to the + block. TOTAL COST: $176. Bought everything at Walmart but the grounding blocks which I got at Home Depot. They are in the home electrical section with the fuse boxes. I can run 2 or 3 bars at a time....

How do you vent the hydrogen gas generated from the charging of the battery?
 

NPS Ranger

Member
May 21, 2010
1,988
Penn's Woods
SlickTop Solutions said:
How do you vent the hydrogen gas generated from the charging of the battery?

He vents it into a 2 liter soda bottle with some aluminum foil and.....


oh wait, that's another thread. :bonk:
 

Medicman695

Member
May 27, 2011
311
USA, MN
NPS Ranger said:
He vents it into a 2 liter soda bottle with some aluminum foil and.....

oh wait, that's another thread. :bonk:

Shhh! your giving away the secret recipe lol!
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
"Car Battery/Battery boost pack


Pros


Cheap


Easy to find



Plenty of amps



Safe to use on LEDs and stobes


Cons


Dangerous to use and charge (gasses)


Will need recharged (limited time running)


No Features/Options"
 

SPMRC

Member
Jun 10, 2011
400
Lubbock, Texas
I have a 12 volt 50 amps power supply somewhere in storage, I would sell it, but it weighs at least 80 pounds, so I don't know about the shipping.


It was for ham stuff, but I have no place where I can put something so heavy.
 

dakarm34

Member
May 21, 2010
523
Clemmons, NC
I snagged a trippe lite pr 30, a 30 amp regulated power supply for $40 off the bay! It works great, I can run my twinsonic and 3 dash lights all at the same time. They have higher amperage units as well.
 

Hoff

Member
Aug 2, 2011
892
SW Ohio/US
How many amps would I need to run just LEDs? The little SOS LED3 lights draw .5 Amps per light and I'm trying to test 4 at home. Would a 14 Amp supply work out fine? Or am I gonna need a more beefy power supply?
 

shues

Lifetime VIP Donor
May 21, 2010
10,269
NW Indiana
Hoff said:
How many amps would I need to run just LEDs? The little SOS LED3 lights draw .5 Amps per light and I'm trying to test 4 at home. Would a 14 Amp supply work out fine? Or am I gonna need a more beefy power supply?

(0.5 amp/light) x (4 light) = 2 amp


2 amp < 14 amp


You should be operating well within your means.
 

Hoff

Member
Aug 2, 2011
892
SW Ohio/US
shues said:
(0.5 amp/light) x (4 light) = 2 amp

2 amp < 14 amp


You should be operating well within your means.

Awesome! Thanks Shues:thumbsup:
 

vista1

Member
May 21, 2010
472
Nebraska
I have a pyramid power supply 10 amp constant with a 12 a surge. I am wanting to power my 2 rotator halogen mini excalibur. When hooked to the power supply it sends it into protection mode. What do I need to get in order for it to turn the lights on and not go into protection mode and where do I get it at. Thanks!
 

Jarred J.

Lifetime VIP Donor
May 21, 2010
11,578
Shelbyville, TN
a bigger power supply
 

shues

Lifetime VIP Donor
May 21, 2010
10,269
NW Indiana
vista1 said:
I have a pyramid power supply 10 amp constant with a 12 a surge. I am wanting to power my 2 rotator halogen mini excalibur. When hooked to the power supply it sends it into protection mode. What do I need to get in order for it to turn the lights on and not go into protection mode and where do I get it at. Thanks!

In my experience, 10 amps continuous should be the just enough to power two 55-watt halogen rotators, once the bulbs have warm filaments and after the motors are already turning. If you have a ammeter with fine enough resolution, you'll see that it takes somewhat more than 12 amps for just a fraction of a second--long enough to get the filaments warm and to get the motors started.


If you have something like an car audio capacitor or sealed lead acid battery available, either could help get you over the hump.
 

cyrix9445

Member
Sep 20, 2011
62
Orlando, FL
Coreyhudson2 said:
Connect both of these 12v "Rails" and you get 38 amps, 2 in parralell you get 75 amps of power!!

http://www.newegg.com/Product/Product.a ... 6817339012


So basically what im saying is go with a computer power supply off of newegg, that is the most inexpensive and least bulky way i know. I have many 12v items running off of these puppies, lightbar included.

I've used computer power supplies to power automotive equipment before as well, but one thing to consider is that most computer power supplies are "sensitive" to sudden changes in power, some more sensitive than others. They have internal protection that trips fairly easily. Right now I'm using a Dell kilowatt PSU to power a Whelen Liberty, and every so often it gets upset when I power on the halogen takedowns.
 

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