[plug] Mobile .mp3 results to date

McMeikan, Andrew andrew.mcmeikan at mitswa.com.au
Fri Aug 20 11:59:50 WST 1999


Just an update,
	I have now given away the linear design.  Since I had to have a
switching reg to keep the 12v stable I have started to play with switching
for the 5v line.  Haven't built a good test load yet but I can safely run
about 4amps of 5v with no heatsinks, so I think I am going good.  Whats the
consensus for 12v for the hard drive?  Is 2A good enough?  

	cya,	Andrew...
... newly converted fan of LM257[6,7]  ...

PS: I am finding that when I measure the amps I am losing volts accross the
meter, also good test loads are awkward.  I am pretty sure I am pumping
5Amps at 5volts, things run warm but still no heatsinks.  With a good test
load and a heatsink I think I can handle 10A

> -----Original Message-----
> From:	McMeikan, Andrew [SMTP:andrew.mcmeikan at mitswa.com.au]
> Sent:	Wednesday, August 11, 1999 9:31 AM
> To:	'plug at linux.org.au'
> Subject:	RE: [plug] Mobile .mp3 results to date
> 
> Hi,
> 	I was thinking of the linear way, and been playing with a switching
> reg to keep the 12v up if the battery gets flat, any chance of a prelim
> circuit description or cost estimate?  Your death toll is impressive, I
> admire your determination if not your recklessness :)
> 
> 	cya,	Andrew...
> 
> > -----Original Message-----
> > From:	Brad Campbell [SMTP:brad at seme.com.au]
> > Sent:	Tuesday, August 10, 1999 8:18 PM
> > To:	plug at linux.org.au
> > Subject:	[plug] Mobile .mp3 results to date
> > 
> > Just in case anyone may be interested, have some quick results on
> > PC power consumption from the development of my 12 v PC PSU
> > 
> > The LOWEST consumption I managed to get was 1.68A while IDLE
> > using a 2.0.35 Kernel. This was with an ASUS P55T2P4 HX Based
> > board and an AMD K6 200 running at 166Mhz (Coz I couldn't be
> > bothered re-jumpering the board after taking out the Cyrix M2)
> > The AMD Draws about 3.5 amps until INIT boots up, then it 
> > dropped down to about 2 amps. Then further to 1.6 while Idle.
> > Average Consumption during a kernel compile was about 3.5 - 4
> > amps.
> > 
> > This was at 13.8 v input.
> > 
> > The Cyrix M2 idled at about 3.5 amps lowest, tho it did compile
> > the kernel faster :p)
> > Average current for a compile was about 5.5-6 amps.
> > 
> > This was with Keyboard, Floppy Drive, Maxtor 850mb Hard Disk
> > ISA Video Card and ISA Ne2000 Network card.
> > The network was connected. Current increased by over 80ma with
> > the network cable disconnected.
> > 
> > This works out about 7 amps at 5 volts.
> > Anyway, based on these figures the linear regulator someone was
> > going to use will be dissipating about 70 Watts..
> > I guess your car would stay warm..
> > 
> > Our power supply is nearly finished.., well at least we have
> > stopped blowing up FET's anyway..
> > It uses readily available, off the shelf parts and is not to hard
> > to build. The transformer winding is the tricky bit, but given 
> > the longest winding is 7 turns, it's not to bad.
> > Details will be available as soon as I can verify that I'm not going
> > to fry any more Hard Disks..
> > Death Toll so far.
> > 
> > One VX Motherboard
> > 3 Hard Disks
> > 14 HexFets..
> > A handful of capacitors.. ( They are fun to blow up )
> > 
> > All in the name of mobile.. linux powered.. music..
> > 
> > On a final note, the lowest power I could get out of WIN95 while idle
> > was about 4 amps.. ditto for DOS.
> > Penguin Power
> > 
> > Brad....


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