What Fast Charging Claims Really Mean
Fast charging speed test results describe how quickly a phone or battery can refill from empty to key milestones using wired power, measured in watts and timed percentages, and they often differ from the simple headline numbers brands promote in marketing. Phone makers like Apple, Samsung, and OnePlus highlight peak wattage figures such as 40W, 60W, or even 120W, but those numbers rarely reflect the full charging session. In real world charging tests, power usually ramps up quickly, plateaus for a while, then slows down to protect the battery as it nears full. That means the impressive wattage printed on a box is only a snapshot, not a complete description of phone charging performance. Understanding this gap matters when you are choosing between an expensive official charger and a third-party plug that might match or outperform the branded option.
Inside the Lab: How Charging Speed Was Measured
To move beyond marketing, testers focused on energy and time, not promises. For power banks, ZDNET’s lab used a HOBOware plug load logger with a 70W USB-C adapter to track watt-hours drawn from the wall every minute, then interpolated when each unit hit 50%, 80%, and 100% charge. For phones, reviewer Adam Doud used a Mecheer power meter to watch real-time wattage while charging a Samsung Galaxy S26 Ultra, iPhone 17 Pro Max, and OnePlus 15 from empty. Each phone went through two runs: one with its original cable and charger and one with an Anker Prime GaN charger and Anker bio cable. This consistent setup turned a fast charger comparison into measurable data instead of guesswork and exposed how long each device spent near its rated wattage versus at lower, sustained levels during a complete charging session.
iPhone, Samsung and OnePlus: Fast-Charging Speed Test Results
In phone charging performance, the numbers tell a mixed story. The iPhone 17 Pro Max, rated for 40W wired charging with its 5,088 mAh battery, briefly exceeded that advertised maximum in the first five minutes before settling down to lower levels. The Samsung Galaxy S26 Ultra’s 5,000 mAh battery, rated at 60W, peaked at 61W and went from empty to full in under an hour, making it the fastest of the three to reach 100%. The OnePlus 15’s 7,300 mAh silicon carbon battery was advertised at 120W, but on the bundled charger it stayed between 20W and 40W, topping out at about 46W. One quotable conclusion from Doud’s data: “The Anker pairing charged the OnePlus and Samsung phones faster than their own chargers, which I find to be simply funny.”
What Power Bank Tests Reveal About Real-World Charging
Power bank testing backs up the phone findings: headline wattage is only part of the story. ZDNET’s Louisville-based lab compared 10 power banks from brands including Anker, Baseus, UGREEN, and Cuktech, timing how quickly each moved from 0% to 50%, 80%, and 100% based on energy drawn from the wall. The Cuktech 15 Air came out on top, reaching 50% in about 26 minutes and 100% in only 54 minutes. An Anker Prime power bank earned an honorable mention because, despite its significantly higher 250Wh capacity, it fully charged in around 100.2 minutes. The Baseus EnerGeek GX11 MiFi highlighted how design can skew numbers: it raced to 50% in a bit over 13 minutes but took more than three hours to reach full, partly because it doubles as a hotspot capable of charging up to 10 devices at the same time.
Buying Advice: Reading Specs and Choosing the Right Charger
These real world charging tests point to two key lessons for buyers. First, treat wattage claims as a ceiling, not a guarantee. Phones and power banks rarely maintain their peak watts for long, instead following a curve that balances speed and battery health. Second, the fast charger comparison shows that third-party gear can compete with or beat official plugs. An Anker Prime GaN charger outperformed the OEM chargers for both the Samsung Galaxy S26 Ultra and OnePlus 15, and power bank tests showed that some lesser-known models charged faster than big-name rivals. When shopping, look beyond the biggest number on the box and check independent lab measurements of charge time to 50% and 100%. That is the practical speed you feel day to day, and it is a better guide than any single watt rating on a spec sheet.
