what's the 3rd conductor for on Dell laptop P/S?

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jcomeau_ictx

Posted: Tue Jan 30, 2007 7:19 pm

Guest

Hi, I want to be able to run my Dell Inspiron 600m using a custom-made
external 18V battery pack at next year's Burning Man. And I can do
this, but the internal battery will not charge from it without that
3rd, inner conductor of the triaxial cable carrying some unknown
signal. I don't have an oscilloscope any more, and would rather not
have to buy one. Has anyone hacked into this and knows what's being
sent over that 3rd conductor, so I can rig a circuit to emulate it?
Googled and found nothing. Thanks -- jc

Charles Schuler

Posted: Wed Jan 31, 2007 5:47 pm

Guest

"jcomeau_ictx" <john.comeau@gmail.com> wrote in message
news:1170199188.138700.324370@l53g2000cwa.googlegroups.com...

Quote:

I can't directly answer your question but will share something with you. If
you take apart a modern Li-Ion battery pack (for a notebook computer) you
will find several integrated circuits and lots of other stuff. Those darned
things are complicated!

Guest

Posted: Thu Feb 01, 2007 6:03 am

all i can say us DONT mess with the charge terminal. most laptop batteries
have highly integrated charge/drain monitoring circuitry that will get
TOASTED if you try to defeat it.

u are far better off stocking up on ten or so extra correct battery packs.
or get a bonified ac adapter that inserts in same place as battery pack.

they are not just batteries anymore, they are power systems all inside the
plastic.

alternately, use a few charged 12vdc car batteries, a 12vdc to 120 vac
inverter and a standard dell 120vac adapter. yes, its ugly but you might
get a few good weeks of performance from the setup Smile

)

"jcomeau_ictx" <john.comeau@gmail.com> wrote in message
news:1170199188.138700.324370@l53g2000cwa.googlegroups.com...

Quote:

jcomeau_ictx

Posted: Fri Feb 02, 2007 12:19 pm

Guest

Quote:

)

"jcomeau_ictx" <john.com...@gmail.com> wrote in message

news:1170199188.138700.324370@l53g2000cwa.googlegroups.com...

Hi, I want to be able to run my Dell Inspiron 600m using a custom-made
external 18V battery pack at next year's Burning Man. And I can do
this, but the internal battery will not charge from it without that
3rd, inner conductor of the triaxial cable carrying some unknown
signal. I don't have an oscilloscope any more, and would rather not
have to buy one. Has anyone hacked into this and knows what's being
sent over that 3rd conductor, so I can rig a circuit to emulate it?
Googled and found nothing. Thanks -- jc

Chris Jones

Posted: Sun Feb 04, 2007 7:45 pm

Guest

jcomeau_ictx wrote:

Quote:

I think I once read somewhere that the power supply contains a Dallas chip
in a transistor-style TO-92 case, that contains a serial number, to prevent
power supplies with the wrong profit margin^H^H^H^H^H^H^H^H^H^H^H^H^H
specifications from being used. Better get yourself a logic analyser, or a
DC-AC inverter.

Chris

Mike Harrison

Posted: Mon Feb 05, 2007 5:11 am

Guest

On Sun, 04 Feb 2007 23:45:12 +0000, Chris Jones <lugnut808@nospam.yahoo.com> wrote:

Quote:

jcomeau_ictx wrote:

Hi, I want to be able to run my Dell Inspiron 600m using a custom-made
external 18V battery pack at next year's Burning Man. And I can do
this, but the internal battery will not charge from it without that
3rd, inner conductor of the triaxial cable carrying some unknown
signal. I don't have an oscilloscope any more, and would rather not
have to buy one. Has anyone hacked into this and knows what's being
sent over that 3rd conductor, so I can rig a circuit to emulate it?
Googled and found nothing. Thanks -- jc

I think I once read somewhere that the power supply contains a Dallas chip
in a transistor-style TO-92 case, that contains a serial number, to prevent
power supplies with the wrong profit margin^H^H^H^H^H^H^H^H^H^H^H^H^H
specifications from being used. Better get yourself a logic analyser, or a
DC-AC inverter.

Chris

Yes - it's a dallas chip to identify the PSU type, in particular whether or not it can supply enough
current for the device it's connected to - there are different Dell PSUs with different current
capabilities with the same plug.
These Dallas chips can be emulated fairly easily with a PIC/AVR etc. as long as you don't need the
1-wire powering facility, which you don't in this case as you have other power available.

Guest

Posted: Mon Feb 12, 2007 1:38 am

also, a good alternative may be a correctly sized solar panel (or two) with
circuitry to charge /offsett battery drain.

"jcomeau_ictx" <john.comeau@gmail.com> wrote in message
news:1170433175.966343.17370@q2g2000cwa.googlegroups.com...

Quote:

Thanks for the advice, but I'm willing to take the risk. Carrying
around a few hundred pounds of batteries is not my idea of portable
computing... my bicycle trailer is going to be full enough with 10
gallons of water plus my camping gear.

On Feb 1, 3:03 am, <hapt...@sbcglobal.net> wrote:
all i can say us DONT mess with the charge terminal. most laptop
batteries
have highly integrated charge/drain monitoring circuitry that will get
TOASTED if you try to defeat it.

u are far better off stocking up on ten or so extra correct battery
packs.
or get a bonified ac adapter that inserts in same place as battery pack.

they are not just batteries anymore, they are power systems all inside
the
plastic.

alternately, use a few charged 12vdc car batteries, a 12vdc to 120 vac
inverter and a standard dell 120vac adapter. yes, its ugly but you
might
get a few good weeks of performance from the setup Smile

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