Why Your Phone Is Charging Slowly (8 Common Causes and Fixes)
Slow charging is almost always the charger, the cable, or the battery — in that order.
Your phone should top up from 0% to 50% in about 30 minutes on modern fast-charge kits. If it's taking two hours or more, one of these eight things is why:
Get a battery diagnostic Diagnostic shows you the actual battery-health number + cycle count.
Common causes
1. Underpowered charging brick
Old 5W bricks or generic 10W bricks can't deliver modern fast-charge speeds. Use the manufacturer's fast-charge brick (20W+ for iPhone, 25W+ for Galaxy).
2. Wrong cable
USB-C to USB-C cables for modern phones must be rated for PD 3.0 (or PPS for Samsung). The cheap white cable that came with your old headphones will not work.
3. Lint in the port
Less contact surface means less current — exactly the symptom of a slow charge. Clear with a toothpick.
4. Charging from a laptop USB port
Laptop USB-A delivers 2.5W — that's trickle-charging territory. Always use a wall outlet.
5. Heavy background apps
A hot phone charges slower because the OS throttles current to stop thermal runaway. Close background apps and try again.
6. Aged battery
At <80% health, charge current drops. Check your battery health (see OS steps above). Replacement is typically $69–$99.
7. Optimised charging pause
Both iOS and Android pause at 80% overnight to preserve battery lifespan. This is normal, not a fault.
8. Charging IC degrading
Rare, but possible after a surge (lightning strike, bad power bank). Symptoms: warm during charging even when idle, and any charger charges slowly. Board-level diagnostic required.
Frequently asked questions
How fast should my phone charge?
0–50% in about 30 minutes on modern fast-charge kits (iPhone 14+ with 20W brick, Galaxy S22+ with 25W Super Fast Charging). If you're seeing 2+ hours from 0–50%, something is wrong — usually the brick, cable, or battery health.
Will replacing my battery speed up charging?
Yes, if your battery health is below 80%. As batteries age, they accept charge more slowly. Below 80% battery health, a fresh battery often restores both daily life AND charging speed. iPhone Settings → Battery → Health shows your current %.
My phone charges fast on the wall but slow in the car. Why?
Car USB and many wireless car chargers deliver lower wattage than wall power. A 12V car-to-USB adapter rated for 18W+ PD will fast-charge most modern phones; a generic car port at 5W will only trickle.
Does Optimised Charging actually slow my phone?
It pauses at 80% overnight to preserve battery lifespan, then tops up to 100% before your usual wake time. This is intentional, not a fault. If you need a full charge for an early flight, turn off Optimised Charging in Settings the night before.
How much does battery replacement cost?
$69–$149 depending on phone. iPhone $79–$89, Galaxy $89–$129. Restores both daily battery life and charging speed. See /repair/{brand} for your exact model.