Why didn't I get max charging speed?
Charging a modern smartphone isn't as simple as plugging it in. Your phone and your charger have to agree on the same fast-charging standard, and the cable has to handle the current.
The standards that matter
- USB-PD (Power Delivery): the universal USB-C standard. iPhones fast charge on any USB-PD charger, 20W or higher.
- PPS (Programmable Power Supply): part of USB-PD that adjusts voltage in small steps. Samsung Super Fast Charging (25W and 45W) and Pixel fast charging need it. A 70W MacBook charger has no PPS, so a Galaxy S25 Ultra charges at only about 15W on it.
- Samsung 45W: needs a PPS charger rated 5 A and a 5 A USB-C cable. With a 3 A charger or cable, it drops to 25W.
The cable bottleneck
Standard USB-C cables are rated for 3 A (60W). Samsung's 45W mode and laptops above 60W need an E-marked 5 A cable. Check yours with our USB-C cable checker.
Frequently asked questions
Why is my phone not fast charging?
Fast charging requires three things to match: a charger that supports your phone's protocol, a cable rated for the current, and a phone that negotiates the higher power. Samsung Super Fast Charging needs USB PD PPS, and 45 W charging requires a 5 A USB-C cable.
What is USB PD PPS?
USB Power Delivery Programmable Power Supply (PPS) lets the phone request precise voltage and current in small steps. It reduces heat and is required for Samsung Super Fast Charging (25 W and 45 W). Chargers without PPS usually fall back to about 15 W on Galaxy phones.
Can a higher-watt charger damage my phone?
No. A quality USB-C charger only supplies the power the phone requests, so a 65 W laptop charger is safe for a phone that charges at 20 W. Avoid uncertified no-name chargers, which may lack proper protections.
What charger do I need for an iPhone?
Any USB-C Power Delivery charger rated 20 W or higher fast-charges recent iPhones. Higher-wattage PD chargers can charge the latest Pro models slightly faster at peak, and a 30 W or higher adapter is recommended for the newest MagSafe charger.