Hi all:) I just got a Garmin Oregon 700 gps and use a TOPO pro card..But I'm surprised that the device use a lot of battery power real fast..I bought the original Garnin 2.4 volt battery pack, but the device still use a lot of battery power in a short time..What's wrong..? I have disconnect the wi-fi and Bluetooth funktion but that doesn't make a big difference..So what else can l do to reduce the battery use..?..And can this device use Rechargeable Lithium 3,6 volt batteries without damaging the device...?