Why your phone charges fast on one charger and slowly on another

A charger and a phone negotiate before any real power flows. The phone says what it can take, the charger says what it can give, and they settle on the highest arrangement they both understand. If they understand each other poorly, you get a safe, slow 5 or 10 watts regardless of what is printed on either one.

USB Power Delivery — the common language

USB PD runs over USB-C and is supported by nearly everything current: iPhone, Pixel, Samsung, most tablets, most USB-C laptops. A good PD charger is the safest single purchase, because it will fast-charge almost anything you own now and most of what you buy next.

PPS is an extension of PD that lets the charger adjust voltage in fine steps instead of fixed jumps. Samsung's fastest wired speeds need it, so if you carry a Galaxy, look for PPS on the charger specification rather than wattage alone.

The manufacturers' own standards

Oppo, Realme, OnePlus, Xiaomi and Vivo each developed proprietary fast charging — VOOC and SuperVOOC, HyperCharge, and so on. These reach their headline numbers only with that brand's own charger and cable, often with a special cable rated for very high current.

Plug one of those phones into a general-purpose PD charger and it still charges perfectly safely. It just will not hit the number from the advertisement. This is the single most common reason someone tells us a new charger is "not working".

Why a 65W charger may give your phone 25W

Wattage on a charger is its maximum, usually across all ports at once. What a phone draws is capped by the phone. A 65W charger feeding a phone that accepts 25W delivers 25W — and that is correct behaviour, not a fault.

Which is why the useful question is not "how many watts is the charger" but "how many watts does my phone accept, and can this charger speak its language".

What to buy

• iPhone, Pixel, most Android: any decent PD charger. Our Anker Zolo 30W at Rs 2,999 covers a phone comfortably.
• Samsung Galaxy at full speed: a charger listing PPS.
• Oppo, Realme, OnePlus, Vivo at full speed: that brand's own charger and cable.
• Phone, tablet and laptop from one plug: a multi-port GaN charger. The Anker Zolo 70W with four ports is Rs 8,999 and runs four devices from one socket.

Two things worth checking before you order

The plug. Some imported chargers ship with flat US-style pins that do not fit a Pakistani socket. We say so on the listing where it applies — see our guide on 2-pin or 3-pin plugs.

The cable. It has its own ceiling, and it is the most commonly overlooked part of a slow charge. We wrote that up separately in why your 120W cable is not charging at 120W.

Tell us your phone model on WhatsApp and we will tell you the charger that matches it — including when the one in your drawer already does.