Troubleshooting pillar · 18 articles in this cluster
iPhone battery problems
The complete diagnostic — what kills iPhone batteries, what fixes them, and when it's time to replace.
Battery problems are the #1 complaint we hear about iPhones. This pillar is the decision tree we use ourselves before recommending a battery swap.
Battery degradation is normal.
Apple rates iPhone 15+ batteries for 1,000 charge cycles to 80% capacity. Roughly 3 years of normal use. If your iPhone is older than that and reports 80-85%, you're in the expected range — not in a failure state.
Read the full battery health methodology →In short.
iPhone batteries are lithium-ion cells with a finite cycle count. Capacity drops as cycles accumulate; software workarounds slow but don't reverse this.
Three classes of battery complaints: legitimate degradation (replace the battery), software regression (update or downgrade iOS), and user misconception (Battery Health screen scares people unnecessarily).
Start with the decision tree below. If your Battery Health reads above 80% and you're seeing rapid drain, it's almost certainly software — not the cell.
The decision tree we use
Five questions, in order. Skip ahead if you already know the answer.
- 01
Check Battery Health first
Settings → Battery → Battery Health & Charging. Read the Maximum Capacity number. If above 80%, the cell itself is fine — your problem is software or usage, not hardware.
- 02
Identify the drain source
Settings → Battery → Last 24 Hours / Last 10 Days. Look for one app at the top consuming 20%+. That's almost always the cause.
Background Activity high on a single app = misbehaving update. Foreground Activity high = you're using that app too much, that's not a fix.
- 03
Restart, then update
Force-restart the iPhone (Vol Up → Vol Down → hold Power until logo). Then check Settings → General → Software Update. A surprising number of 'sudden drain' reports clear after both.
- 04
Reset Network Settings
Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings. Background reconnection attempts to a flaky Wi-Fi network are a common silent battery killer.
- 05
Replace the battery if Health < 80%
Apple Store, authorized service provider, or third-party — depending on your AppleCare status and risk tolerance. $99-$129 USD as of 2026.
Battery health expectations by model
What 'good' looks like after typical use. Anything inside the green range is fine.
| iPhone model | 1 year old | 2 years old | 3 years old | 4+ years |
|---|---|---|---|---|
| iPhone 15 / 16 / 17 (all) | official | official | official | vendor |
| iPhone 14 / 14 Plus / Pro | official | official | vendor | hard |
| iPhone 13 series | official | vendor | hard | no |
| iPhone 12 series | official | vendor | hard | no |
| iPhone 11 / SE 2 | vendor | hard | no | no |
Common error states
| Error / state | What it means | How to fix |
|---|---|---|
| Battery Health unavailable | iPhone hasn't finished calibrating after a battery replacement. | Wait 30 days of normal use. The reading reappears. |
| 'Important Battery Message' | iPhone detected a non-Apple battery and disabled Battery Health. | Either accept it (works fine) or replace with a genuine Apple cell to restore the reading. |
| Battery 'Service' indicator | Health dropped below ~80%. | Replace the battery. Cost: $99-$129 at Apple. |
| iPhone shuts off above 20% | Cell can no longer deliver peak current — even though reported capacity is OK. | Replace the battery. Calibration tricks rarely help once this starts. |
| Charge stalls at 80% | Optimized Battery Charging is doing its job — predicted unplug time is more than 1h away. | Not a fix needed. Or disable Optimized Battery Charging if it bothers you. |
All iPhone battery problems guides
All 3 articles in this cluster, newest first.
Quick answers
The questions about iPhone battery problems we get asked most.
-
Why is my iPhone battery draining so fast?
Almost always one app misbehaving. Check Settings → Battery → Last 10 Days for the culprit.
Read the full answer → -
Is 90% Battery Health bad?
No. That's typical after 1-2 years. Below 80% is when service indicator appears.
-
Should I let my iPhone die before charging?
No. Lithium-ion prefers shallow cycles. Charge whenever convenient.
-
Does fast charging kill the battery faster?
Slightly. The math: ~5% fewer cycles at 27W vs 5W over the device's life. Not worth worrying about.
-
Why does my iPhone get hot while charging?
Mild warmth: normal. Hot enough to be uncomfortable: stop charging and check the cable for damage.
-
How long does an iPhone battery actually last?
Apple rates iPhone 15+ for 1,000 cycles to 80% — about 3 years of normal use.