What Fast Charging Really Means in Everyday Use
Fast charging is the process of pushing higher power into a phone or power bank than standard chargers, but in real-world use the charging speed constantly changes over time and rarely matches the single big wattage number brands promote in their marketing materials. That headline figure describes a short peak under ideal conditions, not the sustained rate you experience from 0% to 100%. Recent tests of flagship phones from Apple, Samsung, and OnePlus, along with premium power banks, show that speed depends on the charger, cable, battery chemistry, and even how full the battery already is. In other words, fast charging is a dynamic curve, not a fixed speed, which is why real charging performance has to be measured over a full cycle rather than guessed from the spec sheet on the box.
How We Tested Phone and Power Bank Charging Speeds
To understand real charging performance, you need more than the percentage shown on a screen. ZDNET’s lab tests power banks by logging energy from the wall with a HOBOware plug load logger, measuring watt-hours at one‑minute intervals from 0% to 100%. Those readings are then summed to find total energy drawn and interpolated to determine how long each unit takes to reach 50%, 80%, and full. As product testing manager Gianmarco Chumbe notes, this method tracks “energy delivered to the charger rather than energy stored in the cells,” so overhead and inefficiencies are included. For phones, another test used a Mecheer power meter to watch real‑time watts delivered to an iPhone 17 Pro Max, Samsung Galaxy S26 Ultra, and OnePlus 15 with both OEM and Anker chargers, then compared total charge times instead of relying on advertised watt ratings.
iPhone, Samsung, and OnePlus: Fast-Charging Claims vs. Actual Speeds
On paper, the iPhone 17 Pro Max supports up to 40W wired charging, the Galaxy S26 Ultra is rated at 60W, and the OnePlus 15 advertises a headline‑grabbing 120W. In testing, the iPhone briefly exceeded its 40W rating in the first few minutes, while Samsung peaked at around 61W, edging past its 60W claim. The surprise was OnePlus: its own charger never approached the promised 120W and instead stayed between roughly 20W and 40W, topping out at about 46W despite the 7,300 mAh silicon carbon battery’s bold marketing. This shows why phone charging speed is more than a single spec: battery size, thermal management, and charging curve all matter. Marketing numbers describe a theoretical maximum; what counts is how quickly your phone moves from empty to full in the real fast charging test.
Third-Party Chargers: When Anker Beats the Originals
Many buyers assume the original charger is always the best match for fast charging, but lab results complicate that assumption. In side‑by‑side testing, an Anker Prime GaN charger paired with an Anker bio cable not only matched but in some cases beat OEM bricks from Samsung and OnePlus. According to ZDNET’s tests, “the Anker pairing charged the OnePlus and Samsung phones faster than their own chargers,” highlighting how a well‑designed third‑party charger can unlock better real charging performance without changing the phone. That does not mean every off‑brand accessory is safe or fast, but it shows reputation and engineering matter more than the logo on the plug. When comparing phone charging speed, it is worth considering trusted third‑party adapters, especially if your flagship phone ships only with a cable in the box.
What Our Tests Mean for Your Next Charger or Power Bank
The phone and power bank comparison data point to one clear lesson: ignore the biggest wattage number on the box and focus on tested behavior. In ZDNET’s power bank tests using a 70W USB‑C adapter, the Cuktech 15 Air reached 50% in about 26 minutes and hit 100% in only 54 minutes, making it the fastest‑recharging unit in the group despite competing against larger banks. Meanwhile, another model from Baseus sprinted to 50% in just over 13 minutes but needed more than three hours to fully charge, showing how curves can differ. When choosing chargers, look for measured 0–100% times, compatibility with your phone’s standards, and credible lab results. That approach will give you a setup that charges quickly in the real world, not just in marketing slides.
