Has anyone tried - or know of anyone who did - doing away with the smps in a typical desktop pc and replacing it with a complete battery based supply ?
The PC psu has +3.3, +5, -5, +12 and -12 outputs. Some of these are at very high currents.
Sequence is also important.
Power input is so high that even car batteries don't power a UPS for long.
If you want battery supply use one of the low power ITX boards or a laptop.
Sequence is also important.
Power input is so high that even car batteries don't power a UPS for long.
If you want battery supply use one of the low power ITX boards or a laptop.
if you are saying that based on what ratings are stamped on your psu then you are not on the right track.
but I can understand where you might be coming from. Older CPUs used 5V are their primary voltage, so older psu have huge 3v and 5v current rating and meagre 12v rating. Newer CPUs use 12V. so as long as you have a good (10-12A) +/-12V line and barely half of those amps on the 3 and 5v lines it should be just fine.
I will try to find an interesting link that gave a very good idea of power supply requirements for a pc.
<edit:>
here it is-
http://firingsquad.com/print_article.asp?current_section=Guides&fs_article_id=1162
but I can understand where you might be coming from. Older CPUs used 5V are their primary voltage, so older psu have huge 3v and 5v current rating and meagre 12v rating. Newer CPUs use 12V. so as long as you have a good (10-12A) +/-12V line and barely half of those amps on the 3 and 5v lines it should be just fine.
I will try to find an interesting link that gave a very good idea of power supply requirements for a pc.
<edit:>
here it is-
http://firingsquad.com/print_article.asp?current_section=Guides&fs_article_id=1162
karma said:
have you worked out any design plans ? would be good to discuss if you're interested.
The Solution:
It is called "Laptop"... Your very own, off the shelf, battery powered PC!
They make those thingies so compact now, you can even carry them with you! Isn't that wonderful?
It is called "Laptop"... Your very own, off the shelf, battery powered PC!
They make those thingies so compact now, you can even carry them with you! Isn't that wonderful?
I ran an AT style (P-200overdrive,IIRC) PC from a 17AH selaled lead acid battery for quite a while one day..
Crude 12V PC PSU
Crude 12V PC PSU
Actually it's quite possible, there are these little SMPS units that can deliver about 100 watts from a 12V battery, easily found on sites that deal with car PCs and stuff.
If you're thinking full linear supply, yes, it's possible, but you'll require lots of regulation and heatsinking unless you're looking for a very small PC (like a P200 overdrive), those things will not require more than 60-70 watts which would translate into 3 hours from a single 17AH battery - assuming no other losses, so you could probably squeeze a 2-hour runtime out of a single charge.
The one thing I could think of something like this is for an 'audio PC' that dispenses with any HF nasties like an SMPS would put out - but it's quite a bit of trouble. A Laptop isn't a solution because the LCD screen is driven by a very noisy SMPS itself. And sois the rest of the electronics... For everything else though, it is the best solution.
If you're thinking full linear supply, yes, it's possible, but you'll require lots of regulation and heatsinking unless you're looking for a very small PC (like a P200 overdrive), those things will not require more than 60-70 watts which would translate into 3 hours from a single 17AH battery - assuming no other losses, so you could probably squeeze a 2-hour runtime out of a single charge.
The one thing I could think of something like this is for an 'audio PC' that dispenses with any HF nasties like an SMPS would put out - but it's quite a bit of trouble. A Laptop isn't a solution because the LCD screen is driven by a very noisy SMPS itself. And sois the rest of the electronics... For everything else though, it is the best solution.
Maybe you could run the 5V and 3.3 lines off a 6V SLA and the 12V off a 12V SLA. For the negative lines a single battery with some 79xx regs should be enough.
Remember even if you run everything off a linear supply, the main CPU Vcore regulators are switching regulators, not linear so you'll still get a bit of switching noise...
Remember even if you run everything off a linear supply, the main CPU Vcore regulators are switching regulators, not linear so you'll still get a bit of switching noise...
percy said:
not at the moment. come spring when the college students go home ill work something out. im sure i could do it but there right it would use up allot of batterys. you could set it up in a car. if thats what your looking for.
😉
however does it (quality and type of power supply) really matter if you are simply extracting digital audio (from spdif) on the motherboard or soundcard to an external dac ?
Actually, it would matter most then. When it would probably not make too much of a difference is if you have a good soundcard with SPDIF and/or you pull the digital audio through USB, which is better than a two-bit sound chip that is used on most motherboards.
I would get a good card with digital out, preferably an entry-pro level card like the audiotrak Maya or the m-Audio Audiophile, and I wold have probably spent less than battery + linear reg + heatsinking and cooling, as these are available around the $150 mark, and don't have issues of heat and/or noise.
I have two digital outputs on my PC, one from the motherboard and the other from my m-Audio delta, and there is a SQ difference between the two. Quite a bit actually.
I would get a good card with digital out, preferably an entry-pro level card like the audiotrak Maya or the m-Audio Audiophile, and I wold have probably spent less than battery + linear reg + heatsinking and cooling, as these are available around the $150 mark, and don't have issues of heat and/or noise.
I have two digital outputs on my PC, one from the motherboard and the other from my m-Audio delta, and there is a SQ difference between the two. Quite a bit actually.
Interestingly, our electronics shop guys are making a full linear PSU for a computer to get rid of noise for a computer running a VERY sensitive instrument. The instrument is so sensitive to noise, it is going to be housed inside a full room sized faraday cage! (Imagine copper mesh for as far as the eye can see!!!)
The PSU is still under development, but if you are interested I can see if they would be willing to share the schematic for general use.
The PSU is still under development, but if you are interested I can see if they would be willing to share the schematic for general use.
You can get the low-power VIA Mini-ITX PCs with a 12V PSU option. These are sometimes used if you want to put a PC in a sailing yacht to provide the navigation computer.
Although the fastest VIA mini-ITX board is only 1.3GHz, they are very small and high quality boards. Have a look at www.mini-itx.com for ideas.
Although the fastest VIA mini-ITX board is only 1.3GHz, they are very small and high quality boards. Have a look at www.mini-itx.com for ideas.
sangram said:
yeah thats the idea, it would be either the soundcard spdif OR the motherboard - or a pci-usb card - usb port, depending on what DAC I end up building.
Currently I have a Turtle Beach Santa Cruz which isn't bad and also has spdif output.
dfdye said:
Would love to see it!!
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