Low Power Mode does save power — but it is not a "power-saving switch." It is a performance limiter: it saves energy by dimming the screen, pausing background refresh, and cutting 5G and the high refresh rate. The good news: it does not harm your battery. The bad news: leave it on all day and the experience you give up is worth more than the power you save.
What it actually limits
Apple's own description is clear. With Low Power Mode on, the system will:
- Dim the screen (you can turn brightness back up manually)
- Pause background app refresh — apps stop updating content in the background, and notifications arrive late
- Limit 5G (except for video streaming on some models)
- Cap ProMotion at 60Hz (iPhone 13 Pro and later Pro models)
- Pause automatic downloads, background mail fetch, and some visual effects
The screen and cellular radio are the two biggest power draws, and every one of these cuts lands on a major artery — so the savings are real. The cost is a phone that feels "dull": no more 120Hz scrolling, no more instant notifications, no more preloaded content.
Does it hurt the battery
No. Low Power Mode is purely a software-level scheduling limit. It does not touch charging voltage or battery chemistry. In Apple's battery and performance guidance it is positioned as a way to stretch existing charge, not a charging-management feature.
One design detail proves the point: Low Power Mode turns itself off once the charge passes 80% — the system's view is "you have enough power, hand performance back to the user." If it harmed the battery, Apple would not allow it to stay on indefinitely.
A quick table: when to turn it on, when to leave it off
| Situation | Recommendation | Why |
|---|---|---|
| Out and about, power won't last until the next charge | On | This is exactly what it is designed for |
| 20% left at bedtime, no charger around | On | Less drain overnight |
| The phone is running hot | Reasonable | Lower brightness and refresh rate also cut heat — see Why Your Phone Gets Hot |
| On all day, every day | Leave it off | Late notifications, 60Hz, paused downloads — the experience costs more than the savings |
| Gaming or navigating | Leave it off | Capped refresh and background hurt exactly these scenarios |
| Fast battery drain in cold weather | Won't help | It limits performance; it produces no heat. Cold-weather drain needs a different fix — see Cold-Weather Battery Drain and Shutdowns |
| An older phone below 80% battery health | Limited effect | It stretches remaining charge; it cannot fix a battery that can no longer feed the processor — see Battery Health Explained |
Two switches people confuse
Low Power Mode is not Optimized Battery Charging: the former manages "do I have enough power right now," the latter manages "will this battery last for years" — by learning your charging routine and delaying the final stretch past 80% (see Apple's Optimized Battery Charging note). They do different jobs, both live in Settings > Battery, and they can be on at the same time.
What you can do now
- Toggle it manually:
Settings > Battery > Low Power Mode; you can also add it to Control Center for one-tap access - If you keep forgetting: use the Shortcuts app to set "turn on automatically below 20%"
- If the battery still drains fast with Low Power Mode on, the problem is not the switch — it is the battery itself or a runaway app. Go back to the framework in Why Your iPhone Gets Laggy