A user equipment (UE), such as a mobile phone, may support multiple power classes. Power classes can define maximum output power levels for uplink transmissions. A base station of a radio access network (RAN) can, based on metrics reported by the UE, dynamically instruct the UE to switch to using a different power class. For example, the base station may instruct the UE to switch from using a first power class with a higher maximum output power to using a second power class with a lower maximum output power, in order to preserve battery life of the UE in situations in which the second power class provides sufficient output power for uplink transmissions to reach the base station.