Macbook Air Battery life
Yes, the i7 will extend battery life when doing processor intensive tasks compared to the i5, but eat up more battery when doing low exertion tasks. The more memory you have, the more battery life will be reduced as well — this is why Apple has kept the RAM relatively low in its mobile devices other than laptops. I do not believe that the size of the SSD should have a negative impact on battery life. The larger drives are faster and so should overall reduce battery usage, however, if the drive is crammed full this will reduce battery life simply because there is more information which needs to be available to be accessed.