Xiaomi promises 5 hours of music playback at 50% volume and the earphones can even exceed that depending on circumstance. We did a full charge and then we listened to music for 5 hours straight at 65% volume. After that TWS2 Basic had about 10% battery left in them.
Making calls eats the battery faster, but that’s to be expected. If you use them one earphone at a time, which is our preferred scenario, you get about 7 hours total of noise-cancelled calls (3.5h per earphone).