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How To Hook Up Two Computer Power Supplies?  
User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Posted (7 years 8 months 2 weeks 5 days 18 hours ago) and read 7244 times:

how to hook up two independent computer power supplies, in series?


The meaning of life is curiosity; we were put on this planet to explore opportunities.
40 replies: All unread, showing first 25:
 
User currently offlineBill142 From Australia, joined Aug 2004, 8439 posts, RR: 8
Reply 1, posted (7 years 8 months 2 weeks 5 days 17 hours ago) and read 7239 times:

uhh.. why?

how are you intending to use them? one to power mobo and cpu and another to power cd and hdd?


User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 2, posted (7 years 8 months 2 weeks 5 days 14 hours ago) and read 7224 times:

Quoting Bill142 (Reply 1):
one to power mobo and cpu and another to power cd and hdd?

Kind of like that, I want one to turn on when the other does.



The meaning of life is curiosity; we were put on this planet to explore opportunities.
User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
Reply 3, posted (7 years 8 months 2 weeks 5 days 14 hours ago) and read 7222 times:

If your are using two power supplies(PS), I imagine you would be connect two ac mains cable (that makes it parallel automatically). The output side (dc side) all the connectors are polarized (does not allow you to connect the wrong connectors to the internal devices), so you can connect to whatever devices in Computer from both PS. So, just select the loads in so that you distribute the loads coming to each PS evenly.


In short, you need not worry about series or parallel, just hook up the primary sides to the ac and keep connecting the dc(secondary) side as though they were from a single supply.

[Edited 2006-11-12 13:25:44]

User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 4, posted (7 years 8 months 2 weeks 5 days 14 hours ago) and read 7212 times:

Quoting TRVYYZ (Reply 3):
In short, you need not worry about series or parallel, just hook up the primary sides to the ac and keep connecting the dc(secondary) side as though they were from a single supply.

Would I need to splice wires or an adapter?



The meaning of life is curiosity; we were put on this planet to explore opportunities.
User currently offlineRichardPrice From , joined Dec 1969, posts, RR:
Reply 5, posted (7 years 8 months 2 weeks 5 days 14 hours ago) and read 7210 times:

Watch out for different earths, even to the same wall socket, it can kill a computer (Ive done basically what you want to do here, and I lost parts due to a differential in the earths on the two supplies).

User currently offlineTedTAce From , joined Dec 1969, posts, RR:
Reply 6, posted (7 years 8 months 2 weeks 5 days 13 hours ago) and read 7201 times:

Dude, unless you are an ET (which apparently you (as well as me) are not) this is stupidity.

If you don't have enough energy comming out of a power supply to power your stuff, butch up and buy a bigger power supply. If you want redundancy, buy a case/motherboard that is designed for dual power supplies. Sure your spending money but you'll be a lot happier when you watch the system power up properly instead of letting the smoke out of the caps.


User currently offlineKlaus From Germany, joined Jul 2001, 21406 posts, RR: 54
Reply 7, posted (7 years 8 months 2 weeks 5 days 13 hours ago) and read 7199 times:

Do not do this. Especially as long as you don't know what you're doing.

It is very likely that you're simply frying both power supplies that way.

If you need a stronger PSU, get one. There is no cheap way around it, especially not this way!


User currently offlineQueso From , joined Dec 1969, posts, RR:
Reply 8, posted (7 years 8 months 2 weeks 5 days 10 hours ago) and read 7177 times:

Quoting Klaus (Reply 7):
Do not do this. Especially as long as you don't know what you're doing.

It is very likely that you're simply frying both power supplies that way.

If you need a stronger PSU, get one. There is no cheap way around it, especially not this way!

 checkmark  Agreed. What it sounds like you are trying to do can be done, but not in a way that is easily explainable in a forum.


User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
Reply 9, posted (7 years 8 months 2 weeks 5 days 10 hours ago) and read 7176 times:

Quoting Lehpron (Reply 4):
Would I need to splice wires or an adapter?

I don't think so, if do it the right way.

Quoting RichardPrice (Reply 5):
Watch out for different earths, even to the same wall socket, it can kill a computer

Be sure to interconnect the two earths/grounds of the two PS on to the Chassis of the PC. I believe you are using two power supplies made specifically for use with PC's and not any ac adaptor lying around.

Also be sure to have a multimeter and you can check for any voltage between the the grounds of two the PS on the dc side before connecting(make sure it is zero V).

As everybody mentioned, margin for error is very small and all protection of PC is on the primary side of PS and not on dc.

[Edited 2006-11-12 18:06:09]

User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
Reply 10, posted (7 years 8 months 2 weeks 5 days 9 hours ago) and read 7154 times:

Another problem I can see with this arrangement is that, if one PS fails, it could overload the other PS and damage it depending on the circuitry.

User currently offlineKlaus From Germany, joined Jul 2001, 21406 posts, RR: 54
Reply 11, posted (7 years 8 months 2 weeks 5 days 7 hours ago) and read 7132 times:

Quoting TRVYYZ (Reply 9):
if do it the right way.

There is no "right way" to do this with off-the-shelf PSUs!

This is much more complicated than just the question of connecting which wire where - and conventional PSUs are simply not built for load sharing, which would be an absolute necessity.

Keep your hands off if you don't want to risk destroying your computer and the PSUs, quite possibly involving a risk of fire for which no insurance would ever reimburse you.


User currently offlineAC773 From Canada, joined Nov 2005, 1730 posts, RR: 2
Reply 12, posted (7 years 8 months 2 weeks 5 days 6 hours ago) and read 7118 times:

Quoting Klaus (Reply 11):
Keep your hands off if you don't want to risk destroying your computer and the PSUs, quite possibly involving a risk of fire for which no insurance would ever reimburse you.

It could potentially be worse. In a standard power supply, certain capacitors can carry enough electrical charge to kill you. Anything over 16 joules will do the trick.

Bottom line? Unless you know what you're doing, don't mess around with power supplies or, for that matter, any kind of computer or electrical component.

A PSU of adequate wattage is a lot cheaper than the price of the components you might fry, the fire you might start, or the ambulance ride you might need.



Better to be nouveau than never to have been riche at all.
User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
Reply 13, posted (7 years 8 months 2 weeks 5 days 3 hours ago) and read 7100 times:

Quoting Klaus (Reply 11):
There is no "right way" to do this with off-the-shelf PSUs

I don't know about the background of the threadstarter or whether he can do it.
It is not easy but not impossible. I work in a lab and we like to experiment these kind of things, may be thats why I find it challenging. The fire hazards are minimal if an approved PS is used ie, UL or TUV mark. They have to be tested for almost all possible faults. In my lab we blowup PS almost every other day  Wink because some of our techs don't change the voltage setting and plug to 240V (Canada is 120V,60Hz)

[Edited 2006-11-13 01:14:04]

User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 14, posted (7 years 8 months 2 weeks 5 days 1 hour ago) and read 7080 times:

Quoting AC773 (Reply 12):
A PSU of adequate wattage

I just need amps on the 12v line, specifically 3 more than what I have, so a small 120W or 180W supply was considered but how to hook up is not obvious to me yet.

Edit: (warning, crazy idea, I just came up with it now): how about hooking up a 12v battery, how much current is there?

Quoting TRVYYZ (Reply 13):
I don't know about the background of the threadstarter or whether he can do it.

Might as well just spit out the whole thing:

My power supply is a Hiper 580W (620W peak) with a combined dual 12v rail maximum of 30 amps. It's pretty good, very quiet, had it for 4 months and I like it. As it stands, I am using approximately 23amps on the 12 volt line at around 290W.

Most of ya'll might know my plan with adding a TEC onto my computer's graphics card:

  • nVidia GeForce 7900GT KO 512meg version.

  • Stock speeds 560/1500MHz.

  • Currently, overclocked 685/1600 MHz.

  • My idle/load temps are 39*C/51*C (Rthdribl.exe for 10mins at full res).

  • Through empirical testing Qout idle/load is 44/70 watts

  • memory chips estimated at 4W each (x8), never measured their temps (I'll get some heasinks for them later).


  • I guess the recent idea (last night) was if I had 7 amps left, why not get a tiny TEC to experiment - but would it make a difference? Even an 80W TEC at 12v would cool no more than 32W worth. I'd need more cooling that the core put out at load to be effective, but those modules are power hungry. That would begin at the 169W, 172W and 226W versions -- that is only if I stop overclocking the core.

    I know how TEC's work, they require up to 2.5 times the power to run than to cool. I have thought of many combinations of doing this with 8 different TEC's including giving the thing its own power supply. I'm not using a water cooling loop as the cpu cooler that was modded onto the gfx card can remove up to 150watts of heat, double what the card is putting out now at 685MHz. I have noticed that whenever I turn on the AC (not usualy on), I can increase the speed with no change in idle/load temperatures!

    I suppose theorhetically, if I moved the computer to the AC cranked it to supercold and began OC'ing some more, I may not need the TEC. Maybe I can use up all the 7 amps left over into the graphic card if I just turn on the AC, the cooler should take it all. I wonder if I could reach the 800's MHz on the core on air cooling? The maxiumum possible is 1120MHz and the highest I've seen online was on the 3Dmark06 benchmark all-time-highs at 1020MHz using custom phase change cooler (cheapest commercially available solution I've seen was $400).

    Other people on other tech forums brag about their speeds and they have spend hundreds in liquid cooling but here I am, having spent $65 and my core is running faster. I want to see how much faster I can push it.

    I wonder, is it absolutely neccesary to get it cold, if all the heat is removed, why not maintain ambient? I have considered PWM TEC controllers bu those things are expensive and I have $150 to play with as of now. I might try the AC idea first before the TEC thing.

    Quoting TRVYYZ (Reply 10):
    Another problem I can see with this arrangement is that, if one PS fails, it could overload the other PS and damage it depending on the circuitry.

    Hmm, for some reason I keep thinking in terms of t=0 on this, and not the idea that the second psu would fail so soon it would cause me problems.

    [Edited 2006-11-13 02:24:26]


    The meaning of life is curiosity; we were put on this planet to explore opportunities.
    User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
    Reply 15, posted (7 years 8 months 2 weeks 5 days ago) and read 7059 times:

    Quoting Lehpron (Reply 14):

    Let me discuss with the hardware experts in my lab for a second opinion.
    I am more of a power guy, I thought synchronising a 3 phase alternator to the power grid was challenging. I enjoy more of the 10kV surges we simulate and 5kV hipots we do.
    Let me see if I can get the detail on the advantages and disadvantages of the arrangement.

    Also, your computer enclosure will be heated more due to all the loads and many of the components many not be rated for this ambient, so the ventillation could be a problem or it will act as heating chamber or unless you are not using an enclosure which then is a safety issue. Most of the component temps should not exceed 90oC and 105oC is the limit for PCB for safe operation.

    [Edited 2006-11-13 03:47:00]

    User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
    Reply 16, posted (7 years 8 months 2 weeks 5 days ago) and read 7054 times:

    Quoting Lehpron (Reply 14):
    12v battery, how much current is there

    The rating of the battery is given in ampere-hours (Ah). If you divide the Ah by the current you draw, it will give you the number of hours it can supply that current.
    Anyway not recommended.

    I have tested li-ion batteries of 3.7V and it gave upto 34A on short circuit (only for a second or two) and then about 12-14A for about 10 minutes. Short circiut of a AAA baterry cangive upto 4 or 5A upto a few minutes.
    Please note: We have a fire extinguisher handy when we do the crazy tests Wink


    User currently offlineRichPhitzwell From , joined Dec 1969, posts, RR:
    Reply 17, posted (7 years 8 months 2 weeks 4 days 22 hours ago) and read 7039 times:

    you could do a wake on lan... but that usually requires a second MB and NIC. as for starting up two power supplies without all that hassle, Crestron makes a devise that starts and turns off computers with the press of a button. I should warn you, this is a hard boot. cost a couple of hundered dollars.... of course you could do the same thing with a standard switch and some bios settings... if thats all your after.

    anyways, im drunk
    =)


    User currently offlineTedTAce From , joined Dec 1969, posts, RR:
    Reply 18, posted (7 years 8 months 2 weeks 4 days 21 hours ago) and read 7030 times:

    Back to the fucking TEC shit again  Sad

    I should have known better...

    Lephron, just say  no 


    User currently offlineRichPhitzwell From , joined Dec 1969, posts, RR:
    Reply 19, posted (7 years 8 months 2 weeks 4 days 21 hours ago) and read 7024 times:

    ok, so im not as drunk as before...how are you able to get 23 amps out of anything...most single phase breakers commercial are only 20 amps. residential is either 15 or 20 amps.... most desktops including crt monitor on startup are around 5.2ish amps... now im really curious, please explain!

    User currently offlineTedTAce From , joined Dec 1969, posts, RR:
    Reply 20, posted (7 years 8 months 2 weeks 4 days 21 hours ago) and read 7019 times:

    Quoting RichPhitzwell (Reply 19):
    now im really curious, please explain!

    You don't want to know.... Instead of using a fan, liquid, liqud nitrogen, or anything else that normal people user to cool his system: Rocket boy wants to use what's called a Thermal Electric cooler. I fell in love with the technology when I saw it on a motorcycle helmet (in 1988) and that made some sense. Then I fell out of love when I read some of the earlier threads on this subject and read how much energy it takes, and how poor the efficiency is. The boy might as well use a catheter; with the right tubing and lighting it should look pretty cool.


    User currently offlineRichPhitzwell From , joined Dec 1969, posts, RR:
    Reply 21, posted (7 years 8 months 2 weeks 4 days 21 hours ago) and read 7016 times:

    Quoting TedTAce (Reply 20):
    You don't want to know.... Instead of using a fan, liquid, liqud nitrogen, or anything else that normal people user to cool his system: Rocket boy wants to use what's called a Thermal Electric cooler. I fell in love with the technology when I saw it on a motorcycle helmet (in 1988) and that made some sense. Then I fell out of love when I read some of the earlier threads on this subject and read how much energy it takes, and how poor the efficiency is. The boy might as well use a catheter; with the right tubing and lighting it should look pretty cool.

    Yes but he said he is drawing 23 amps now.. im curious how he is able to do this in the usa off of a 110v 20a circuit unless he is using a 220, 277, 440...circuit.


    User currently offlineDrDeke From United States of America, joined Jun 2005, 830 posts, RR: 0
    Reply 22, posted (7 years 8 months 2 weeks 4 days 20 hours ago) and read 7011 times:

    Quoting RichPhitzwell (Reply 21):

    Yes but he said he is drawing 23 amps now.. im curious how he is able to do this in the usa off of a 110v 20a circuit unless he is using a 220, 277, 440...circuit.

    When he says 23 Amps, he means 23A at 12V on the DC rail of his power supply. That's 276 Watts, quite easy to obtain from a 115VAC 15A circuit, even with PSU overhead  Smile.

    -DrDeke



    If you don't want it known, don't say it on a phone.
    User currently offlineTRVYYZ From Canada, joined Oct 2004, 1369 posts, RR: 10
    Reply 23, posted (7 years 8 months 2 weeks 4 days 9 hours ago) and read 6995 times:

    My discussion results:
    Can be done. But is it worth the trouble? Only if you are an enthusiast and willing to take chances.

    Some links on some people who have done things like this:
    http://www.moddin.net/review.asp?ReviewID=34&PageNo=1
    http://www.abxzone.com/forums/showthread.php?t=72633
    http://www.abxzone.com/forums/showthread.php?t=32829

    Didn't read the whole thing but seems mainly how to turn on the PS by shorting the green and black wires of the motherboard connector.


    User currently offlineRichPhitzwell From , joined Dec 1969, posts, RR:
    Reply 24, posted (7 years 8 months 2 weeks 4 days 8 hours ago) and read 6983 times:

    Quoting DrDeke (Reply 22):
    When he says 23 Amps, he means 23A at 12V on the DC rail of his power supply. That's 276 Watts, quite easy to obtain from a 115VAC 15A circuit, even with PSU overhead .

    Ahh, never try to do math when drunk off your arse!


    25 Post contains images David L : He's going to design us a cheap, environmentally friendly SST on it. Leave him alone!
    26 Lehpron : The lowerest temperature a fan will 'cool' is ambient, no matter how many rpms or cfms there are. I'm usually in an environment with no AC. since mos
    27 Sprout5199 : Listen to Klaus. We use 24v-50amp PSs for our microwave system and transmitters where I work. If we need more than 50 amps we buy 2 PS but one is a m
    28 Post contains links TedTAce : Until you get your electric bill. http://www.freepatentsonline.com/4483021.html http://www.freshpatents.com/Crash-he...ling-dt20060518ptan20060101556
    29 WSOY : Connecting two power supplies in series: 12+12 = 24 V -no problem, if you keep the ground and case of the "top" one isolated. It's easiest to resolve
    30 WSOY : The components in approved power supplies will by regulations not propagate fire even if they are heated to the exteme by a fault themselves. It's ex
    31 WSOY : The chances of a kill are small, but you might receive a jolly good jolt. That is if you're acting really fast -- the discharge (bleed) resistors tha
    32 Bobster2 : What about all the external devices with separate power supplies? Why can you have separate DC power supplies outside the box but not inside the box?
    33 WSOY : That's a good question, and there's a short answer. The lab supplies' "0" output line is not connected to the metal case/ground as it is in the compu
    34 Sprout5199 : Its thinking this way that get people killed and buildings burned down. Any time you misuse any PS you are asking for trouble. I have seen too many P
    35 WSOY : So have I, accidentally. Modern computer switching power supplies by the way do not apply Crowbar circuitry. That was in the analog times. We have no
    36 Sprout5199 : The PS that I use still have them, astrons and such.If it aint broke dont fix it. More of a brute force PS than anything else. 40 to 50 amp supplys.
    37 Post contains images Runway23 : Use a pince, they roughly look like this:
    38 WSOY : There really is no need to use a crowbar circuit in switching mode supplies, and none of the consumer grade units I've seen in the past 10-15 years h
    39 Post contains links Sprout5199 : Hmmm a challenge. see this: http://www.deprep.org/2001/TB01L25B.PDF page 3. not a "death" but mentions what we are talking about. was first thing i r
    40 Post contains links WSOY : Computer power supplies are nowhere near the high kilovolts range. Working back from the report get that the high voltage capacitor was 2mF and the en
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