What shook me up was the realization that a flight stored in a
Cambridge logger will disappear when the battery dies. At least with
the model 20, I don't think there's any low-battery warning. So
someone who drops off their logger in the scorer's office could be in
for a rude shock the next morning. It wasn't something I thought about
because I've always downloaded from the logger to my PDA which has a
non-volatile (i.e., flash) memory card which doesn't rely on a battery
to refresh it. Last week I did take to leaving my LNAV-GPS/NAV
switched on after I landed until after I verified a successful flight
download. I'll probably continue to do so in the future.

Regarding the Compaq 1530/1550, the primary and, eventually, backup
batteries are slowly depleted if you don't put the PDAs on the charger
every few weeks (or more often if the battery is not so new) because
of the necessity to keep the built-in memory alive. I can't say
whether the Compact Flash memory card absorbs any power but it doesn't
need any to maintain that memory (where my flights, waypoints, and
airspace are stored). I've not experienced any trouble leaving my
three 1500 series PDAs on charge most of the time between flights. Is
that not the case for the newer PDAs?

Chip Bearden
ASW 24 "JB"
USA