The g700 is a bit weird with the battery life
I have it and it has 3 modes, Power saver, Normal gaming, and Max gaming
Max gaming is pretty much the mouse pretending that it is connected through USB. It does not use any power saving.
Normal gaming will go into a low power state after a few minutes of not being used, and power saver is your classic battery powered mouse mode where where the laser will switch to a very low polling rate within like 5 seconds of you not moving the mouse
The polling rate from the mouse to the USB receiver is pretty much always the same (what you set, so on any mode, lowering the polling rate will increase battery power)
Max gaming mode and 1000Hz polling rate will drain the batteries in about 6-8 hours (hope you have the USB cable or extra AA rechargeable batteries on hand
)
It seems the G this time around is designed with a more energy efficient sensor. (the biggest power usage on the G700 was that 5700 dpi sensor)
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For the user claiming a 2 hour battery life on the g700, make sure you didn't get a bad battery.
it should be a sanyo eneloop battery and with the settings maxed out, you should be getting 6-8 hours of use, and on power saver you should get a few weeks depending on use (though powersaver can drain the mouse quickly if you are playing a game where the mouse is constantly moving)