[ltp] Auxilliary external batteries

[Bob Toxen]

Keep in mind that all these auxiliary external batteries are is a
12V rechargeable battery, charger, and inverter.  My R31 used about
150 mA (from the wall) with the display active and the disk spinning
and next to nothing without the disk running.

If the inverter is 75% efficient, call that 200 mA.  This is 24 W,
requiring 2 A from a 12 V battery.  For a 30% disk duty cycle, that is
an average of 0.67 A.  For a 12 hour transatlantic (must be Pacific)
flight, that would require an 8 AHr battery.  a 50 W inverter would
work fine.  Actually, you would get 15 hours because when the inverter
battery runs down you still would have a fully charged internal battery.
Mine is spec.'ed for 3 hours.

     50W inverter: $25 at www.microcenter.com (about 0.3 pounds)
        or about the same price at www.batteriesplus.com
     7.5 AHr 12V sealed lead acid battery would weigh 6 pounds
        Model CLTXPA12-7.5F via www.batteriesplus.com $26
     Battery charger (1A would recharge in about 10 hours)
        2.5 pounds via www.batteriesplus.com $17
     ===========================================================
     Total cost $68
     Total weight 8.8 pounds

     Quality construction, fully warranted, easily replaceable.
     Note: Batteries Plus does not ship from its web site but
     their Duluth, Georgia store does mail orders +770 495-1644.
     (They have batteries for absolutely anything; I'm not affiliated
     with the company.) Hmmm.  I might just do this for my upcoming
     talk in San Jose.

     The form factor and weight of the above might be slightly less
     desirable than the commercial products but at a fraction of the
     price, unless someone else is paying for it, it's a no-brainer
     to me.  The knuckle-draggers at airport security might get
     suspicious and cause you hassles with a home-brew solution, though.

Bob Toxen,
Fly-By-Day Consulting, Inc.
http://www.verysecurelinux.com       [Network & Linux/Unix Security Consulting]
http://www.realworldlinuxsecurity.com [My 5* book: "Real World Linux Security"]
bob@verysecurelinux.com (e-mail)

The talks I'm giving on Linux security this year include:
  at IBM's Linux Competency Center in New York City on March  6
  at the Atlanta SecureWorld Expo in Atlanta        on May   22
  at the Enterprise Linux Forum in San Jose         on June  04