only 31m screen on.
it might be that you carrier dose not support fast dormancy, this is turned on by default and if your network dose not support it
your battery will drain faster than normal when using data connection (could possibly be the cause of reboots if they are linked with 3g)
in the build.prop look for this part:
ro.config.hw_fast_dormancy=1 #bit 0: fast_dormancy, bit_1: smart_network_search ro.config.hw_fast_dormancy_ap=true
change it to:
ro.config.hw_fast_dormancy=0 #bit 0: fast_dormancy, bit_1: smart_network_search ro.config.hw_fast_dormancy_ap=false