If you feel like your fancy new iPhone 12 or Galaxy S21 isn't getting quite the battery life you'd like, T-Mobile has a solution: turn off 5G.
The carrier appears to have updated its site following a story from PCMag, but up until recently its support page for Samsung's Galaxy S20 Ultra 5G offered the tip, "Toggle from 5G/LTE to 2G" as a way to improve battery life. Verizon similarly suggested in a now-deleted tweet that battery drain could be addressed by switching a phone to LTE-only mode.
Granted, carriers have for years suggested downgrading a phone's connectivity to older cellular technology as a way to save battery life. But suggesting customers turn off 5G certainly contradicts the expensive marketing campaigns these companies have rolled out touting their futuristic new networks. That's probably why both Verizon and T-Mobile were quick to scrub the idea.
5G network issues — Newer 5G networks can consume more battery power because people will download more, for one. But 5G networks also aren't yet widespread, meaning a phone will spend more time looking for a good connection. Apple has tried to address 5G drain in the iPhone 12 with Smart Data Mode, which uses 5G not when it's available but when it thinks a customer needs those fast download speeds.
In a support page on its own site, Samsung explains another issue causing battery drain with 5G: the technology only communicates data right now, not phone calls or SMS messages. That means smartphones need to connect to both LTE and 5G networks simultaneously, whereas LTE alone is capable of carrying both data and voice/SMS.
These issues should be alleviated as carriers allocate more of their network spectrum to 5G frequencies. Right now, only a small slice of spectrum has been sliced off 4G networks and reassigned to transmitting higher-frequency 5G.
Considering that 5G speeds in most areas aren't materially faster than 4G LTE, this is all more evidence that you shouldn't upgrade your phone just to get the latest cellular tech.