The Realme P4 Power, launched earlier this week, boasts a remarkable 10,001mAh battery. Realme markets it as a power bank alternative, highlighting its 43% thinner design at 9.08mm and 14% lighter weight of 219g compared to typical 10,000mAh power banks. But does the P4 Power actually function as a power bank? We put it to the test.
We started the experiment with the Realme P4 Power fully charged and an iPhone 17 Pro nearly out of battery, sitting at just 7%. We connected the devices using a USB C-to-C cable equipped with a real-time charge speed measurement device.
Test start: 22W of power, iPhone at 7%Initially, the P4 Power delivered 22W to the iPhone. To achieve maximum reverse charging speeds, the screen on the P4 Power needs to be turned off, as it conserves power for its own functions otherwise.
After 10 minutes, the charge speed decreased slightly to 19W, with the iPhone 17 Pro reaching 23% battery while the P4 Power had 94% remaining. Check out our video here to see the reverse charging in action.
At 30 minutes, the charge speed dropped further to 11W; the iPhone was at 48%, and the “power bank” rested at 80%. This scenario reflects casual use, such as charging a friend's phone for 10-30 minutes. With the iPhone at 48%, the user would likely have enough battery for the remainder of the day.
Curiosity led us to continue the test. After 50 minutes, the iPhone reached 65% with a charge speed of 9W, while the Realme stood at 70%. We concluded the test after 70 minutes, recording a charge speed of 7W; the iPhone's battery was at 70%, and the P4 Power's battery was down to 61%.
Test timeline: start • 30 minutes in • end at 70 minutes
For reference, in our review of the iPhone 17 Pro, we utilized a 45W Pixel AVS charger, achieving 70% charge in 30 minutes and a full charge in 1 hour and 18 minutes. To be fair to the P4 Power, it's worth noting that most phones do not support AVS as an input, while the P4 Power advertises a maximum reverse charging power of 27W. Our testing device confirmed that the two phones negotiated USB PD at 9V and up to 3A.
The results are telling—the Realme P4 Power can fully charge an iPhone 17 Pro once. Despite some could expect it to achieve two full charges based on battery capacities alone, conversion losses prevent that from happening.
The Realme P4 Power acting as a power bankNonetheless, a 10-30 minute top-up is more common for users. Impressively, even if you charged a friend's iPhone to full capacity, the P4 Power would still hold enough battery to provide hours of gaming until you return home.
Lastly, we need to examine how quickly the Realme P4 Power itself charges. With 80W SuperVOOC charging, Realme claims it can recharge from 0-50% in just 36 minutes—a matter we will test in the future.
