How is the Battery Life in the I7 compared to the I5 with GPU

I know than it should be less but almost all reviews are comparing the I5 No GPU vs I7 GPU.

I5 GPU and i7 GPU should not make so much difference in the battery life right?
 
all depends on what you are going to do with the device.

This will determine how the processor runs and in turn, affect the battery life
 
There might be an hour or 1:30 difference with keyboard attached and probably more like 20-30 min with keyboard removed. But it all depends on how you use it, and what you use it with. All in all, i5 will always get better battery life.