USB PD, PPS, Qi2, MagSafe, mAh, Wh and more — what each one means when you buy a charger, cable or power bank.
The small, reversible connector on most phones, tablets and laptops made in recent years, and on every iPhone from the iPhone 15. The connector carries charging and data; how fast it charges depends on the charger and cable.
Apple’s connector on iPhones from the iPhone 5 to the iPhone 14 family. It fast-charges on a USB-C Power Delivery charger with a USB-C to Lightning cable.
The USB-IF charging standard used over USB-C. Charger and phone agree on a voltage — 5, 9, 15 or 20 V — before charging starts, so a phone only takes what it can use. It goes up to 100 W, and to 240 W with USB PD 3.1.
Part of USB PD 3.0: the charger adjusts its voltage in small steps that the phone asks for, which keeps the phone cooler at high power. Samsung’s Super Fast Charging and the top wired rates of most Pixels need a PD charger with PPS.
Qualcomm’s fast-charging standard, mostly on USB-A ports. It raises the voltage in small steps, up to about 18 W. Many Android phones support it; iPhones don’t.
Charging power: volts × amps. A 20 W USB-C charger can deliver 9 V at about 2.2 A. More watts charge faster only if the phone is built to take them.
The capacity of a battery. Phone batteries are about 3,000–5,000 mAh; power banks are rated at their cells’ 3.7 V, so only about 60–70% of their mAh reaches the phone.
The energy stored in a battery: mAh × volts ÷ 1,000. Airlines set power bank limits in Wh — up to 100 Wh in hand luggage.
The Wireless Power Consortium’s wireless charging standard, used by iPhones and most Android phones. Plain Qi pads have no magnets, so the phone has to sit in the right spot.
The newer Qi standard with magnets that snap phone and charger into line (the Magnetic Power Profile, based on Apple’s MagSafe), at up to 15 W; Qi2.2 goes up to 25 W.
Apple’s magnetic wireless charging for iPhone 12 and newer. Magnetic chargers and power banks snap onto the back; iPhone 16 and newer take up to 25 W from a compatible MagSafe charger.
A USB-C cable with a small chip that tells the charger it can carry 5 A. Charging above 60 W (20 V × 3 A) needs one; 100 W and 240 W cables have it.