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

Ipuvaepe

Member
Jun 25, 2011
884
Southeast Pennsylvania
Just remember to not smoke near it.
 

wfd67

Member
May 25, 2010
207
San Francisco area, CA
Jtsou said:
What I did was make a plywood box, housing an old PC powersupply, with about 52amps on ONE(1) single 12V rail. I mounted the powersupply in the box and ran the AC cord out of the box. I took a SPST switch and connected one end to ground on the powersupply and the other end to the GREEN wire on the 20 pin motherboard connector(someone earlier mentioned jumping the purple wire to ground, that is a 5v wire and jumping that is not good...) This way, I can cut the powersupply on and off at my leisure. I took 3 cigar lighter sockets and mounted them in the box, wiring them to a 12v lead from the power supply. I also ran a 12v "hot" post and a ground post on top of the box with alligator clips so if i needed something besides a cigar socket, i had it. You can also use the 3.3v and 5v leads if you choose to.

I thought this was a rockin' idea -- and at least in my part of the country, these things are dirt cheap by the pallet-load. (And thanks for the GREEN wire tip -- saved me lookup the pin-out to fire it up!)


Here's the question: any experience / issues with the wires on many/most PC power supplies being on the small side relative to the potential load of a fully lit up bar? So far I've only connected it up to four LED bulbs in a hokey retrofit within an MX7000 bar, just trying not to burn down our leased space. ;)


The goal we're aiming for is an array that can power up a stack of bars in a venue open to others... lovin' the PC supply idea versus the AC-to-DC inverter (keeps costs down)... just not looking to see sparks when visitors press the "light 'er up" buttons. Thanks!
 

toon80

Member
May 24, 2010
2,487
Laval, Canada
Hi wfd67!


This link here might have been posted before but here it is again:


How to Convert a Computer ATX Power Supply to a Lab Power Supply: 13 steps (with pictures) - wikiHow


How to convert a Computer power supply.


If I understood your question correctly, you are referring to the wires delivering 12Volts from the power supply being too small too handle the juice of a big bar. In this link, the guy groups the yellow 12Volts wires together at the connection post. I tried it with 2 PC power supplies and it worked great. The wires are not hot to touch. The only thing is it seems that PC power supplies sometime don't handle the "cold crank" amperage pull of some bigger bars.


I had a JetSonic (4x 50 watts rotators) that, when lit up with bulbs being cold, stopped the PC power supply straight. When the bulbs were hot, though, I could keep going.


Some newer PC power supplies have tripping/overload protection so you don't fry it if you ask too much out of it.


Here's a mini Code 3 XL, with 4x 30 watts bulbs, running from a CORSAIR CX 430 modified power supply, using the method linked above. The 12 Volts rail can supply up to 28 amps.


Hope this helps!


ai767.photobucket.com_albums_xx311_toon80_Mini_20Code_203_20XL_th_DSCN0422.jpg
 

toon80

Member
May 24, 2010
2,487
Laval, Canada
You're welcome!


Thanks for the compliment. My mini-XL has now changed color until next Chritmas ;)


I hope your project turns out well! :thumbsup:
 

infernoemeq

Member
Nov 23, 2010
295
us,kentucky
i seen a vid on youtube or her with a man that had lights all over what look to be his basement,


and had them on a switch box,


that is what i need,


can anyone help me with this,
 

rad123

Member
Aug 5, 2011
896
Dixon, CA
Is this what your talking about Infernoemeq.


and the other video is on my next post
 

rad123

Member
Aug 5, 2011
896
Dixon, CA
and


I wonder how he got the power from the switches to the lightbars. That must call for a lot of wiring! Here's what he says he runs it on:


I power the system with 2 27 series deep cycle batteries, that have a 2 bank Minnkota battery charger that stays hooked up all the time, keeping the batteries topped off. I also use a battery switch to unload the system.
 

Wheels

Member
May 23, 2010
400
El Paso, Texas
Would it be easier and inexpensive to attach a portable battery jump starter to a switch box, such as FS SW400...which is then connected to a lightbar? I assume those jump starters provide a lot of amps, correct?


ai31.photobucket.com_albums_c357_saleenxp8_ps.jpg
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Wheels said:
Would it be easier and inexpensive to attach a portable battery jump starter to a switch box, such as FS SW400...which is then connected to a lightbar? I assume those jump starters provide a lot of amps, correct?

ai31.photobucket.com_albums_c357_saleenxp8_ps.jpg

That works fine, I use this system for testing bars. .... you get about 3 minutes of power on a full bar though. These are meant for cranking amps, not a long term power source.
 

diggerdug.517

Member
Sep 20, 2010
350
Michigan
I need to set up a Unity RV-26 at a local business to run off 110 down to 12 Volt. Anyone know of any inverters that are better than any others ?? Want it to be reasonably priced also.


digger
 

kadetklapp

Member
May 21, 2010
1,568
Indiana
This is what I use to bench-test and run display equipment in my collection (for short periods of time).


[Broken External Image]:http://cn1.kaboodle.com/hi/img/2/0/0/7d/f/AAAAAmxW6UEAAAAAAH34fQ.jpg?v=1193106210000


I've been doing this for several years with the same power pack and have had no problems. I originally bought this after a nasty tornado went thru my area and we were without power for several hours (it has a 110v inverter behind the flip-down). Eventually I bought a genset, but this still serves as backup power, jump starting, and of course lightbar testing/operation. This thing holds a charge well, I probably charge it up every three months.
 

shues

Lifetime VIP Donor
May 21, 2010
10,269
NW Indiana
diggerdug.517 said:
Anyone know of any inverters that are better than any others ??

An inverter takes DC as its input, and makes AC as its output.


A power supply takes AC as its input, and makes DC as its output.


For your application, you need a power supply, not an inverter.
 

toon80

Member
May 24, 2010
2,487
Laval, Canada
Another advise is to get a power supply that has good amperage margin. The cold start of a beacon/lightbar could trip your power supply if the margin is too small. I.e: a 7-8 amps beacon might be too much to start on a 10 amps power supply.
 
May 21, 2010
1,030
LKN, NC
I just did the ATX mod last night and wow...


I had a 600W power supply laying around from my old computer and I have been needing a way to test lighting set-ups on a work bench before tearing out the interior of my truck. It was incredibly easy! All you need are pairings of yellow wires (+12V) and black wires (ground). Also, leave yourself an extra ground to tie into the green wire ("power ON"). All of the other wires, just snip and cover the ends (electrical tape should work just fine).


After about an hour, I had it all buttoned back up and I'm reading 12.71 VDC off both of my leads. My particular power supply provides 20A off the +12 VDC rail...MORE than enough to test any LED project I would work on.


For connectors, I'm a fan of Anderson Powerpoles (I get mine from Powerwerx: Online Shopping for Anderson Power Products Powerpoles, Wouxun Radios, Wire & Cable, Adapter Cables, Powerpole Power Splitters, West Mountain Radio RIGrunner & more). You buy the individual components (which are available in different colors to match your wire color), and make your own pigtails.


[Broken External Image]:[URL]http://inlinethumb48.webshots.com/687/2657465560079783134S600x600Q85.jpg[/URL]
 

jdh

Member
May 21, 2010
1,555
Geneva, FL
vonirkinshtine said:
I just did the ATX mod last night and wow...

I had a 600W power supply laying around from my old computer and I have been needing a way to test lighting set-ups on a work bench before tearing out the interior of my truck. It was incredibly easy! All you need are pairings of yellow wires (+12V) and black wires (ground). Also, leave yourself an extra ground to tie into the green wire ("power ON"). All of the other wires, just snip and cover the ends (electrical tape should work just fine).


After about an hour, I had it all buttoned back up and I'm reading 12.71 VDC off both of my leads. My particular power supply provides 20A off the +12 VDC rail...MORE than enough to test any LED project I would work on.


For connectors, I'm a fan of Anderson Powerpoles (I get mine from Powerwerx: Online Shopping for Anderson Power Products Powerpoles, Wouxun Radios, Wire & Cable, Adapter Cables, Powerpole Power Splitters, West Mountain Radio RIGrunner & more). You buy the individual components (which are available in different colors to match your wire color), and make your own pigtails.


[Broken External Image]:[URL]http://inlinethumb48.webshots.com/687/2657465560079783134S600x600Q85.jpg[/URL]

I have been using them for years to power edge bars. It is really easy to do, and much cheaper then a Switching Supply.
 

JustynC

New Member
Jul 18, 2012
7
Phoenix, Arizona USA
Lots of very useful info in this thread. I do have a question, I have a S&W lightbar model WW3-78 I think thats what it says(ID plate is weathered. Anyway I was using an old Sears 2/10 amp 12v car battery charger to run it. I loaned the charger to a friend who accidentally backed over the charger and well you know. So he gave me as a replacement a Schumacher 12 volt 2/12/75 amp fully automatic starter charger. Ok this is the question, I usually use 12 amps but what would happen if I switched it to 75amp? Would that blow the bulbs out and send the rotators flying? I normally just use the rotators when I play with it (the lightbar).


Thanxx


JustynC
 

stansdds

Member
May 25, 2010
3,533
U.S.A., Virginia
To my knowledge, amperage will not blow out bulbs, excess voltage will blow out bulbs and motors, but too low amperage can damage motors. Your lights will only draw enough amperage to properly power them, so a 75 amp supply should be fine as even the Code 3 Triple Threat will draw about 41 amps (without speakers). Now running that same bar on a 30 amp power supply will result in bulbs glowing dimly and motors turning slowly and probably a good amount of arcing going on inside the motors. The bigger question with these chargers is how "clean" is the power being supplied (spiking or steady output)? And is that 75 amp setting just to crank a starter and not for sustained use?
 

mkent

Member
Mar 11, 2012
207
united kingdom
these days its simple,safe and affordable to run your lightbars from the household supply(240v in the u.k.)


forget car chargers,car batteries etc etc...


buy a p.s.u pulled from a computer(p.c) that is rated 600/700 watts 12vdc.


with a bit of rewiring,you have it.


i have a h.p fan assisted power supply pulled from a p.c that is rated 550 watts. its input is 120/240v and output is 47amps at 12vdc.clean and safe voltage.


it will not cause damage to strobe supplies,transistors in sirens or l.e.ds.


i can run a aerodynic model 24 eah and a nypd aerotwin at the same time with no issues.


no heavy transformers,no wires getting hot.


perfect..


i will be offering these ready to go in the classified section very soon.
 

dcb

Member
May 21, 2010
211
Lexington, Fayette Co, KY
I have several 12V power supplies for powering various lights and devices. Most are similar to the Astron type, which are bulky and heavy and don't travel/ship easily.


Looking for suggestions for a small, compact, lightweight 12VDC power supply. Something under 15A will definitely work, under 10A will probably be OK. Will be mounted under a portable display or inside a Pelican case.


Suggestions?
 

Captain4164

Member
May 3, 2012
952
California
Ok, Ive read thru this thread, and it may as well be written in a foreign language. I dont understand Amps, Watts, etc.


My question is this. Is there a way I can have one power source, and have the leads off each light or light bar run to a common place and turn each on on by itself, then switch the leads from another bar, to run it, then switch to a beacon and run it. Im thinking for the Areos and Jets I have of getting a small switch, like a Federal SW400, run power to that and just plug in a bar and run it, unplug that bar, and plug in a different bar.


Make sense??
 

ex416

Member
Apr 28, 2011
1,021
West Central Wisconsin
Captain4164 said:
Ok, Ive read thru this thread, and it may as well be written in a foreign language. I dont understand Amps, Watts, etc.

My question is this. Is there a way I can have one power source, and have the leads off each light or light bar run to a common place and turn each on on by itself, then switch the leads from another bar, to run it, then switch to a beacon and run it. Im thinking for the Areos and Jets I have of getting a small switch, like a Federal SW400, run power to that and just plug in a bar and run it, unplug that bar, and plug in a different bar.


Make sense??

i use a single 35 amp power source hooked up to a FS sw300 (6 switches) and use quick disconnects for 6 power and 6 ground leads running from the sw300. can have 6 lights hooked up at once and turn them on/off individually and if need be can switch over to other lights fairly quick. depending on the amps the lights draw you can run more than one at a time. the 1st switch on the sw300 is rated at 40 amps w/the remaining ones rated at 20 amps each. (i'm not sure what the amp rating is for the switches on a sw400 - its probably similar to the sw300). you will need to know what the amp draw of each of your lights (can be calculated by adding up the total wattage of the bulbs and then dividing by 12 and then adding the amps each motor draws).
 

Captain4164

Member
May 3, 2012
952
California
ex416 said:
i use a single 35 amp power source hooked up to a FS sw300 (6 switches) and use quick disconnects for 6 power and 6 ground leads running from the sw300. can have 6 lights hooked up at once and turn them on/off individually and if need be can switch over to other lights fairly quick. depending on the amps the lights draw you can run more than one at a time. the 1st switch on the sw300 is rated at 40 amps w/the remaining ones rated at 20 amps each. (i'm not sure what the amp rating is for the switches on a sw400 - its probably similar to the sw300). you will need to know what the amp draw of each of your lights (can be calculated by adding up the total wattage of the bulbs and then dividing by 12 and then adding the amps each motor draws).

Sounds like exactly what I wanna do. GOt any pics of that set up, or a diagram so it can be duplicated? RIght now all I have is the two Aeros and two Jetstreams. Have a few little beacons, a Federal 184, so I would imagine the biggest draw is gonna be the Aerodynics, and I wouldnt be running more than one at once.....i guess.......unless i had a power supply that could handle more than one at once
 

Captain4164

Member
May 3, 2012
952
California
Ok, Ive learned just a little bit more in talking to ex416 in PMs. Thanks Ken for taking the time to help me understand this. Appreciate your time and patience!


Will a Federal SW 400SS box work as a common controller to operate the Aeros and Jets each separately? They are listed as saying the slide switch has a max amp rating of 60 amps, position 1 at 20, position 2 & 3 combined at 40 amps. Im thinking the Aeros, position 1 is the rear amber sealed beams, position 2 is the rear sealed beam ambers and the front red sealed beam solid and flasher, position 3 is all 8 rotators, two TCIs, and the two front red sealed beams. Seems to me the higher rating for the switch should be in 3, not 2, unless all the amps add up thru 1, 2 and 3. I may just try to find a Unitrol, I know those work, cuz thats what we have in the engines we are taking these bars off of
 

toon80

Member
May 24, 2010
2,487
Laval, Canada
The load for the switches position will be the sum of whatever is activated at the time the slide is in that position.


position 1:


rear amber flasher, (assuming 4414 bulbs) 1,5 amps


position 2:


front steady burns (assuming 2x 35watts bulbs) 70 watts/12 volts. Say 5.5 amps + 1,5 amps(rear flasher) total =7 amps


Position 3:


6 rotators + 2 TCLs (assuming eight (8) 55 watts bulbs and almost negligible amps for motors) = 440 watts/12 volts= 36.7 amps + 7 amps = more or less 45 amps in position 3.


A battery will do the job, but be careful with in-home battery safety.


A power supply that will handle the "cold-pull" of 8 lamps ( 6 rotators + 2 TCLs) will be hard to find. The brief start-up of the bar can significantly increase the juice needed for a short burst of time. I have a similar AeroDynic that pulls 40 amps with everything on, and it sometimes trips the power supply, although it's capable of giving 50 amps. Batteries have no problem giving that kickstart, when charged, but they drain...
 

timmy

Member
Sep 9, 2012
97
Southern California
hi....


i have obtained, cleaned up, and mounted two Aerodynic Model 22 (Mini) lightbars on wooden stands for display. i put a 12vdc 30amp power supply i bought on amazon.com into each stand and wired this all up. i am running into the problem with each one of "start up surge" requirements that are just a little too much for these power supplies. i can get a couple of more power supplies and parallel them since i know that works with my larger aerodynic LAPD bar but that would be overkill. so here is my question - could i incorporate a start capacitor into the circuit to get me through the initial surge requirement without adding another power supply into the system...? the issue does appear to be the halogen bulb startup requirement because once the bulbs are warm it easily makes it through the surge but won't when the bulbs are cold. these bars are four light/rotar and not the two light/rotar/mirror configuration - i have one of the two light versions that has no trouble getting through the startup surge when cold with only one of the same power supplies.


timmy
 

shues

Lifetime VIP Donor
May 21, 2010
10,269
NW Indiana
timmy said:
hi....
i have obtained, cleaned up, and mounted two Aerodynic Model 22 (Mini) lightbars on wooden stands for display. i put a 12vdc 30amp power supply i bought on amazon.com into each stand and wired this all up. i am running into the problem with each one of "start up surge" requirements that are just a little too much for these power supplies. i can get a couple of more power supplies and parallel them since i know that works with my larger aerodynic LAPD bar but that would be overkill. so here is my question - could i incorporate a start capacitor into the circuit to get me through the initial surge requirement without adding another power supply into the system...? the issue does appear to be the halogen bulb startup requirement because once the bulbs are warm it easily makes it through the surge but won't when the bulbs are cold. these bars are four light/rotar and not the two light/rotar/mirror configuration - i have one of the two light versions that has no trouble getting through the startup surge when cold with only one of the same power supplies.


timmy

Instead of using an actual capacitor, perhaps you might consider placing a sealed lead acid battery in parallel with your power supply to act as a capacitor. This is the sort of battery found in computer battery backups, also known as uninterruptable power supplies. They are similar in composition to automotive batteries, which are more than capable of meeting the start up surge current requirements you have. However, unlike automotive batteries, with sealed lead acid batteries there is no problem with venting hydrogen gas. They are intended to be used indoors.
 

timmy

Member
Sep 9, 2012
97
Southern California
good idea. if i wired it in parallel with the power supply it would drain when the power supply was not on - i guess a relay that kicked it in when i turned on the power supply would solve that. wouldn't the battery overcharge though if the power supply was left on for a while?


timmy
 

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