I've got 132 waypoints of the Great Wall throughout Beijing loaded onto my Garmin GPSmap 60CSx. I have been testing lithium batteries to get an idea of how long they last so I will know how many to bring. Along with the far superior life of the lithium batteries, and the fact that they tolerate cold temperatures well, they are far lighter than alkaline batteries. One AA alkaline is 23.7 grams and the lithium is 14.5 grams. There are two downsides. First, they are far more expensive, but it looks like the longer life makes up for the cost although I don't have exact figures yet. Second is a problem I have read about but not witnessed myself: at 1.78 volts, they are right at the power limit and the GPS sometimes won't work with them until they are used in a flashlight or something to bring the voltage down slightly. It only takes about a minute, and I doubt they lose much capacity in the process, though. Fortunately, I have not been able to reproduce this problem so maybe my receiver's voltage regulator is calibrated to a slightly higher voltage.
I got a 2GB SanDisk MicroSD card (only $10!) which will be plenty to hold maps and saved tracks.
It looks like no China topo GPS map will become available and I guess I will just have to get the basic Garmin world map.
