The amplification circuits in HA uses power. If the aid has Bluetooth function, it’s another circuit requiring it’s own power. So the battery drain will certain increase if you use any Bluetooth (or Wi-Fi) streaming on your aids. The specs on a 312 battery is 150 mAh and would last approximately 170 hrs, whereas the 13 battery is rated 290 mAh and lasts about 330 hrs. So I would say that if you intend to stream a lot, go for the bigger HA that uses the 13 battery.