Watch out if you get the radio shack adapter it puts out +12 volts on
the plus side referenced to ships ground and - 7 volts on the - side
referenced to ships ground for 19 volts. If you want to connect
anything else to your computer that is using ships ground then you
have 7 volts between them and you get an arc maybe blow some stuff up,
for those that want to argue with this just read very carefully the
warning on page 9 (I think, been a while, maybe page 5) of the manual
it is criptic but it is a warning. I had a customer with one of these
and he blew up his 900 dollar ptc-pro sailmail modems!! So I
investigated and found that they move the negative down from the
input reference.

Watch out !

It is good for running your laptop and for charging batteries but you
must disconnect it before you hook anything else up to the computer.
Charge up the battery then disconnect it. Then connect your fax and
radio stuff.

GW




Glenn Ashmore wrote in message ...
Go to Radio Shack and get a 19V cigarette lighter converter.

Or he http://www.powerstream.com/ADC.htm


TB wrote:
Would it be possible to have the house and engine batteries conected in
series to give 24v, step this down to 18v to power the laptop. Then tap
off each battery for normal 12v service. Sorry if this is a dumb
question but I need a dc supply as the inverter interferes with the ssb
radio when receiving weather faxes.
Tony