Ken,
Even with new laptops that do not have the old Nicad batteries and
therefore supposedly do not develop a memory, it is still advisable to
remove the power suppl,y occaissionly and let the battery run flat.
This is recommended by both IBM and Toshiba.

Incidentally, if I run my laptop off inverters, no matter when they
are far away or near, big or small, I get visible noise when pulling
down weather faxes - not so bad most of the time that the chart is
unusable but annoying. I used to just run the laptop on its internal
battery at fax times. In the Canaries I bought a small "voltage
converter" that is switchable at increments of 1 and 2 volts from
between 15 to 24 volts output for 120 watts. It is not a small radio
shack type and is quite heavy and solidly built. - Cost - $35 Euros or
about US$46. The French boats use them a lot. It never shows any noise
to interfere with reception. This particular one is "Noru" - works a
treat.

regards
Peter

I have to agree with all that Larry said. See above.

Also, my older IBM Think Pad is regularly used with a 75 watt
cigarette lighter inverter with no trouble at all. I added a
cigarette lighter socket to the back of the chart table a few years
ago just for this, though it's handy for other things as well. I
have, on occasion, used the laptop on a larger inverter that displays
output in watts and don't remember ever seeing it draw more than 40
watts. I'm not in the habit of letting the laptop battery run down
too far before recharging as I see it as a backup power supply and
don't want it dead if we're using the lap top for navigation.