What “fast charging” really means in day‑to‑day use
Fast charging speed test results compare a phone’s advertised peak wattage with how much power it draws over time, revealing the real charging speed you feel in everyday top‑ups and full charges. Rather than focusing on a single headline number like 40W, 60W, or 120W, these tests track how quickly a battery moves between milestones such as 0% to 50%, 80%, and 100%. That approach exposes how phone charging performance changes during a session and how close devices come to their claimed limits. Recent lab work on power banks shows why this matters: when ZDNET’s lab timed 10 models, one unit hit 50% in about 13 minutes but then slowed sharply, taking over three hours to fill completely. The same pattern shows up in phones, where early rapid charging often hides slower, efficiency‑driven curves later on.
Inside the test: iPhone, Samsung and OnePlus under the meter
To see how marketing claims compare with reality, ZDNET contributor Adam Doud charged three flagships from dead to full: iPhone 17 Pro Max, Samsung Galaxy S26 Ultra, and OnePlus 15. The iPhone has a 5,088mAh lithium‑ion battery rated for 40W wired charging, Samsung a 5,000mAh battery rated at 60W, and OnePlus a 7,300mAh silicon‑carbon pack advertised at 120W. Each phone was tested twice: once with its own cable and charger (where provided) and again with an Anker Prime GaN charger and Anker bio cable. A Mecheer power meter logged power draw in real time, giving a detailed view of wattage over the full session instead of a single peak figure. This method mirrors ZDNET’s power‑bank lab testing, which also measured input energy over time to derive precise charging milestones instead of relying on manufacturer estimates.
The shocker: OnePlus falls short while Samsung and iPhone overachieve
The headline result from this flagship charger comparison is that the most aggressive claim delivered the least impressive real charging speed. OnePlus 15, marketed at 120W, never came close to that number; it spent its entire session around 20W to 40W and peaked at 46W on its own plug. By contrast, Samsung’s Galaxy S26 Ultra, rated at 60W, briefly exceeded its spec, topping out at 61W. The iPhone 17 Pro Max also pushed past expectations, spending its first five minutes above its 40W rating. According to ZDNET, “Samsung was surprisingly agile, going from dead to fully loaded in under an hour,” while the larger‑battery OnePlus finished in the middle of the pack. The takeaway: a higher advertised wattage does not guarantee the fastest complete charge or better phone charging performance in practice.
Third‑party chargers vs OEM: when Anker pulls ahead
Charger choice proved as important as the phone itself. Apple only includes a cable with the iPhone 17 Pro Max, and Samsung does the same with the Galaxy S26 Ultra, so many buyers will pair these phones with third‑party plugs. In testing, an Anker Prime GaN charger plus Anker bio cable outperformed some original equipment combinations. ZDNET reports that the Anker setup charged both the OnePlus 15 and Galaxy S26 Ultra faster than their own chargers, highlighting how real charging speed depends on both sides of the connection. At the same time, tests of 10 power banks with a constant 70W USB‑C adapter showed wide variation in how quickly each model reached 50%, 80%, and 100%. Together, these findings show that compatibility and charging algorithms can matter more than brand logos or isolated wattage numbers printed on the box.
How to read fast‑charging claims before you buy
For buyers, the gap between marketing and measured results means a few simple rules can help. First, treat any big wattage label as a brief peak, not a promise of sustained power. Look for independent fast charging speed test data that shows time to 50% and full, which is a better proxy for your daily experience than a single number. Second, remember that charger choice matters: a capable third‑party plug from a reputable brand can match or beat some OEM options, as shown when Anker hardware outpaced OnePlus and Samsung chargers. Finally, think about your own habits. If you often need a rapid top‑up, pay attention to early‑phase charging curves, much like ZDNET’s power‑bank tests that track 50% and 80% milestones. Real‑world measurements, not bold packaging, are the safest guide to dependable phone charging performance.
