Chrome and Firefox drain batteries really fast. When I use Chrome on my MBP, I have 2 to 4 hours less battery life compared to Safari. Google / the Blink developers really don’t care about draining the battery. It is infuriating because Opera, Vivaldi and other browsers using the Blink engine suffer from the same problem. Safari has come a long way, both in terms of battery savings and usability. I use Safari Technology Preview[1], which is the most up-to-date version of Safari. Apple releases an update every two to four weeks.

[1] https://developer.apple.com/safari/technology-preview/