I think the problem is with the 189 version, my phone was making 5/6 hours of sot and always very hot, since i updated to version 191 the heat problem disappeared and with Bluetooth always on connect to my fossil gen 5, 4g and wifi on I have done 10 hours of sot in two days of usage. On a single day I normally do 5/6h and I still have 50 % left