No, 16GB won't noticeably drain your battery.

The difference in power draw between an 8GB and a 16GB DDR4 stick is tiny — think a few hundred milliwatts at most. Your screen, CPU, and Wi-Fi are the real battery hogs. If anything, having more RAM means your laptop will swap less to the SSD, which actually saves power.

Just make sure the new stick matches the speed (DDR4-2666) and voltage. If you’re not already running dual-channel, you might lose a bit of memory bandwidth by going single-stick 16GB instead of two 8GB sticks, but that’s a performance trade-off, not a battery one.

The extra 8GB will make your laptop feel faster and more responsive. That’s a better trade than the millisecond of extra battery drain.