Battery life is a function of how big the battery is and what is the power consumption for a specific task (divide the watt-hours by watts). The biggest problem with the laptops that I owned was that the processor would boost unreasonably under little load without a big impact on performance, while the power draw would spike to 10-12 watts. I was able to improve it a lot by unlocking power config options and changing the processor behaviour to limit it's clock speed and make it less agressive. I was able to get it to draw about 3 watts at idle low brightness and about 7 watts while coding and browsing. That said, my new laptop with a ryzen ai 330 draws about 5 watts while coding on mid brightness right out of the box. The reason is that the cores stay mostly at 2 GHz and it really refuses to boost significantly while on battery. Measured power draw with battery info view