On Mon, 21 Feb 2011 05:42:43 -0800 (PST), whisky-dave
wrote:

On Feb 19, 4:26*pm, (Dennis Boone) wrote:
* If one knows the voltage for the laptop, they could make a 12 to 24 V
* input DC|DC converter that outputs the right voltage to the laptop. *(A
* technician with nothing to do in his spare time should be able to get
* the parts, assemble and test this in no time).

Um, it's not quite trivial. *Most boost converters are low-current
devices. *Most laptops these days require between 5 and 8 amps, at
their nominal input voltage, to operate. *That's a lot of current
for a throw-together project.

I think Apple advise not to run a laptop without the battery present
as the 'power' from the converter isn't enough to fully drive the
laptop.
Although it's probbaly be OK for most things.

Apart from anything else, the battery acts as a giant smoothing
capacitor and smoothes out most of the ripple and harshness of the
power supplied by most invertors.


You _can_ get these things, but they're typically the size of your
laptop's existing power supply. *Some laptop vendors actually put
the functionality in the laptop supplies in the first place. (Dell)
Otherwise, look at the likes of Targus.

De

Regards,

Eric Stevens