PSU's and Power

  • Thread starter Thread starter Phillip Parr
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Phillip Parr

Hey peeps! I'm just wondering if any of you lot have experiance with sucking
power out of a PSU. What I mean is, if a PSU is quoted as having 17A
available on the +12V line does that mean I can constantly suck 17A out of
it or will it explode/be unstable/melt etc and if so how much can I
constantly use safely?

Thankies!
 
Phillip said:
Hey peeps! I'm just wondering if any of you lot have experiance with sucking
power out of a PSU. What I mean is, if a PSU is quoted as having 17A
available on the +12V line does that mean I can constantly suck 17A out of
it or will it explode/be unstable/melt etc and if so how much can I
constantly use safely?

Thankies!
Click to expand...

If a power supply is rated to provide 17 amps then it should provide 17 amps.

But it's not that simple. For one, the el-cheapos simply don't tell the
truth. So who knows? And that's about all one can say when the data isn't
reliable.

A proper specification, however, also says under what conditions it'll
provide 17 amps. Like at 25C (or whatever they specify) and give a
de-rating curve for operation above 25C. And, of course, the case insides
usually isn't at 25C.

And last, operating things at 100% load continuously shortens the life span.
 
Phillip said:
Hey peeps! I'm just wondering if any of you lot have experiance with sucking
power out of a PSU. What I mean is, if a PSU is quoted as having 17A
available on the +12V line does that mean I can constantly suck 17A out of
it or will it explode/be unstable/melt etc and if so how much can I
constantly use safely?
Click to expand...

If it is UL listed as +12v @ 17a, it should provide +12v @ 17a all
day long, since that is where UL ran its temperature tests. If, on
the other hand, it is NOT UL listed for +12v @ 17a, your guess is
as good as anyone.
 
David Maynard said:
If a power supply is rated to provide 17 amps then it should provide 17
amps.

But it's not that simple. For one, the el-cheapos simply don't tell the
truth. So who knows? And that's about all one can say when the data isn't
reliable.

A proper specification, however, also says under what conditions it'll
provide 17 amps. Like at 25C (or whatever they specify) and give a
de-rating curve for operation above 25C. And, of course, the case insides
usually isn't at 25C.

And last, operating things at 100% load continuously shortens the life
span.
Click to expand...

Thanks for that info, unfortunatly the el cheapo I've found doesn't seem to
have a spec (damn shops own brands!). The reason I ask is the best power
adapter I can find power wise (and not into extortionate money) supplys 5A @
12V for £18.75. But I had the idea of using a PC supply as they're cheaper,
this 17A one is only £10.
 
ric said:
If it is UL listed as +12v @ 17a, it should provide +12v @ 17a all
day long, since that is where UL ran its temperature tests. If, on
the other hand, it is NOT UL listed for +12v @ 17a, your guess is
as good as anyone.
Click to expand...

Thanks for letting me know! I guess I'll just have to try it :)
 
Phillip Parr said:
Thanks for that info, unfortunatly the el cheapo I've found doesn't seem
to have a spec (damn shops own brands!). The reason I ask is the best
power adapter I can find power wise (and not into extortionate money)
supplys 5A @ 12V for £18.75. But I had the idea of using a PC supply as
they're cheaper, this 17A one is only £10.
Click to expand...
Hi Phillip,

You won't get a decent PSU here in the UK for less than about £35.00
With PSU's, you definitely get what you pay for. And to be honest, by buying
one for a tenner or so, you are just storing up trouble for yourself. Why
risk your whole PC for the sake of some decent power.
Have a look at the likes of Enermax, Antec, Thermaltake, Tagan etc.

HTH
SteveH
 
Phillip said:
Thanks for that info, unfortunatly the el cheapo I've found doesn't seem to
have a spec (damn shops own brands!). The reason I ask is the best power
adapter I can find power wise (and not into extortionate money) supplys5A @
12V for £18.75. But I had the idea of using a PC supply as they're cheaper,
this 17A one is only £10.
Click to expand...

If you only want to get 5 amps out of it then it doesn't matter whether it
does 17 or not.
 
That depends on the quality of the components used in the construction of
the power supply unit. If the pSU is manufactured by a high-end
manufacturer like ANTEC, then yes it can. If it's a generic low-cost power
supply like most people use, then the answer is NO, you'll burn out at LEAST
the PSU if you try that.
 
sorry Steve had to jump your post...I no longer have the OP, thank you
highwinds for another superb job, well done...I digress........


The reason I ask is the best

Power adapter?..... you want to use the 12v rail of a PSU type 'ATX'
to........jump your car?
You are going to use it to power something other than a PC? 17 amps...pretty
big draw, powering an audio amp? I would never draw the 'max' rating on any
appliance, at the very least, it 'pops' and that's all, worst case, it
starts a fire.
 
JAD said:
sorry Steve had to jump your post...I no longer have the OP, thank you
highwinds for another superb job, well done...I digress........


The reason I ask is the best


Power adapter?..... you want to use the 12v rail of a PSU type 'ATX'
to........jump your car?
You are going to use it to power something other than a PC? 17
amps...pretty
big draw, powering an audio amp? I would never draw the 'max' rating on
any
appliance, at the very least, it 'pops' and that's all, worst case, it
starts a fire.
Click to expand...

I wanted to draw about 15A from it to power a portable peltier cooler, the
psu itself would be in the hot airflow section having several cubic meters
of ambient air poured over it each minute.

Phil

<snip>
 
DaveW said:
That depends on the quality of the components used in the construction of
the power supply unit. If the pSU is manufactured by a high-end
manufacturer like ANTEC, then yes it can. If it's a generic low-cost
power supply like most people use, then the answer is NO, you'll burn out
at LEAST the PSU if you try that.
Click to expand...

The great advantage of that is it'll be covered by the shops yearly
warrenty, so even if I burn it out every 6 months I'd get a new one free!
Mwah ha ha ha.

Phil

<snip>
 
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