At 09:59 PM 11/29/2001, Brian and Carol Megas wrote:
>to use the digital camera en-route, saving/posting exceptional pictures to
>friends/family and the home computer.

Make sure you can edit them locally and scale them down to reasonable size
(25-100Kbytes each) before sending.

>   The concern was whether there would
>be problems with the power supply to the laptop

You can get 12v laptop supplies from Targus and others for around $100, or
use an inverter and the regular AC supply.

>or exceptional drain on the
>battery

Depends on the laptop -- speed and nice displays are your enemies.  My
Thinkpad A20m (500 MHz, 15.1" 1024x768 *lovely* display) draws potentially
up to about 7 amps at 12v when using it while the battery is charging
(though I've never measured more than about 5.5).  No problem when you're
running the motor but a serious consideration for battery
use.  Older/slower/smaller machines use less juice.  The 7 amps on mine
might only happen when two batteries are installed, vs one battery and the
CD drive.  I use it on a boat with 300 A-H of capacity so I can run for a
while even though it's my biggest single load (radar is next, about even
with running lights) -- but it means an hour of the engine for every six to
ten of the laptop.  When my batteries are near flat it takes 10-12 hours of
charging with a 35-amp alternator and a smart regulator to get them up to
90% or so.

We don't do long-term camping with the Westy but if we did it would be a
serious consideration -- might have to use a lower-drain machine as well as
institute real battery and charging arrangements.  OTOH in the Westy I'd
run the machine much less -- I run it a lot on the boat to keep it warm and
try to keep condensation out of it.

There's also an enormous (and $$$) laptop battery available that sits under
the machine like a pad and would stretch out your running time
considerably.  As I recall it's around $400 and has about four times the
capacity of the $200 second battery that fits my machine or the $170 spare
regular battery (which are 38 watt-hours each nominal).

david

>- obviously I know nothing about how all this works, I just want
>someone to tell me it's possible and how best to go about it.

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"