Battery powered PC ?

[percy]

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 ?

[karma]

i guese you could but it would be a lot of work.

hmm i got one to spare ill try it.

[davidsrsb]

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.

[percy]

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...rticle_id=1162

[percy]

Originally posted by karma

hmm i got one to spare ill try it.

have you worked out any design plans ? would be good to discuss if you're interested.

[Bakmeel]

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?

[DigitalJunkie]

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

[sangram]

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.

[sangram]

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...

[karma]

Originally posted by percy



have you worked out any design plans ? would be good to discuss if you're interested.

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.