On 2011.02.19 11:26 , 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.

Who said "boost converter"?

5 - 8 amps? Why? Most laptops run around 30 - 50 W. So at 18V or so
that would be a measly ~3A output.

DC-DC converters are what are in the power bricks for laptops: Xfrmr
takes 100 - 250 VAC down to 18 - 36, thence a bridge rectifier, thence
into the DCC converter and out to the laptop at the desired voltage.

http://www.vicr.com/cms/home/product...cro-converters

is an example of a basic DCC converter. For a laptop the "micro"
would do with the supplier configuring it for the desired voltage.

We've put these together for field demos (unattended systems with solar
to battery - no inverters at all - just a good charge controller to the
batteries). Assign it to a bushy tailed tech, tested it and off it
went. Other option is to assign it to whatever engineering coop student
happens to be chained to a desk.

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