How quickly does the iPhone 15 Pro Max really charge? And is Apple’s 20W charger truly the best option for getting the most out of your device’s charging capabilities?
These are the questions we aimed to answer in a detailed charging test conducted on the iPhone 15 Pro Max, designed to cut through common myths and provide a clearer understanding of the device’s actual performance.
Battery Specs and Setup
The iPhone 15 Pro Max comes equipped with a 4,441mAh battery. While Apple officially states that it supports charging speeds of up to 20W, past models have shown that the iPhones often charge at slightly higher rates under the right conditions.
To investigate further, we used a 30W USB-C charger from a trusted third-party manufacturer, paired with the USB-C to USB-C cable included in the iPhone 15 Pro Max box. The test was initiated with the phone at just 1% battery.
Charging Test Results: Faster Than Expected
During the initial 17 minutes of charging, the iPhone 15 Pro Max consistently drew close to 26 watts of power. This is already higher than the 20W speed that Apple claims as the maximum, clearly indicating that the phone can handle more power — at least temporarily.
This finding confirms that investing in a charger rated higher than 20W can be beneficial. A quality 30W charger is a safe bet, and even a 25W charger would outperform Apple’s standard 20W option.
Charging Curve: How the Speed Changes Over Time
However, this high-speed charging doesn’t last throughout the entire process. After around 17 minutes, the power draw begins to drop gradually, falling to about 21W. This phase continues until the 30-minute mark.
At that point, the charging rate drops again, this time to around 15W. The phone maintains this rate for roughly 12 minutes, until the 42-minute mark.
Then comes a more pronounced decline. Between 42 and 47 minutes into the charging session, the power delivery sharply decreases. By the 47-minute point, the iPhone is charging at just 8 watts — a much lower speed that it maintains for the next 10 minutes.
Beyond this stage, the charging speed slows down even more, entering a trickle phase that’s common in most lithium-ion battery charging systems. This gradual tapering helps preserve long-term battery health but extends the time it takes to fully top up the phone.
Final Thoughts: Should You Upgrade Your Charger?
This test effectively debunks the long-standing belief that Apple’s 20W charger is the optimal choice for the iPhone 15 Pro Max. In reality, the phone can handle higher power input during the first stages of charging, and using a slightly more powerful charger can significantly reduce the time it takes to reach a high percentage.
While the benefits taper off toward the end of the charging cycle — due to built-in software that slows charging to prevent overheating and preserve battery life — the initial gains are enough to justify using a 25W or 30W charger instead of the basic 20W option.
