Q: What is the battery life of these recorders?
A: Run time estimates vary significantly depending on two primary factors, 1) power available and, 2) current draw. The OE (factory supplied) battery is a 4600 mAH capacity (722 and 744T) cell which under typical situations will power the unit for approximately 2 hours. Batteries in large capacities (+7000 mAh) are usable with the 7-Series.
The 7-Series battery mount is Sony L- and M- compatible, removable, 7.2 V lithium ion rechargeable cell. Batteries of this type are available in capacities up to 7000 mAH. We have yet to see a "typical" usage, however, fully loaded usage at the highest bit rate with four inputs, outputting timecode, writing to a 5400 rpm HD is less than 1 A (@ 7.2 V). This means that the included 4600 mAh on-board battery can deliver at least 4 hours.
Don't forget that the unit can easily be powered by typical bag power solutions, which typically have even higher power capabilities; the unit can be powered by external DC, 10-18 VDC. Note that the current draw on the external DC will be higher if the on-board cell needs to be charged. The 7-Series operates just like most notebook computers if external power is applied; it will run the unit and charge the removable cell (if needed). Just like our mixers, there is no performance benefit from powering from higher or lower voltages. As long as the power supply (or battery) provides the necessary voltage and current, the unit's switching power supply will generate the necessary voltages for operation.