The Realme P4 Power was unveiled earlier this week and its key feature is its massive 10,001mAh battery. In the press materials, Realme compares it to a normal 10,000mAh power bank and says the phone is 43% thinner (it’s 9.08mm thick) and 14% lighter (weighs 219 grams). That’s impressive, but can you actually use the P4 Power as a power bank? We decided to test it.
Here’s the setup – We started with a fully charged Realme P4 Power and an almost drained iPhone 17 Pro, which was only at 7% battery. We connected both of them with a USB C-to-C cable and a device that can measure the charging speed in real time.
Test start: 22W power, iPhone at 7%
Initially, Realme was shipping 22W on the iPhone. Note that to reach maximum reverse charging speed, the P4 Power’s screen must be turned off (otherwise, it reserves power for its operation).
After 10 minutes of testing, the charge speed dropped slightly to 19W and the iPhone 17 Pro was already at 23%, while the Realme P4 Power still had 94% left in the tank. Watch our video here to see reverse charging in action.
30 minutes after start, the charging speed dropped to 11W. At this point the iPhone was at 48% and the “power bank” was at 80%. We think this is the most likely real-world scenario – topping up a friend’s phone for 10-30 minutes. At 48%, the iPhone user will have enough to get through the rest of the day, job done.
But out of curiosity we moved ahead. After 50 minutes of charging, the iPhone had reached 65% (with charging power dropping to 9W) and the Realme was at 70%. We ended the test after a total of 70 minutes – at that time charging was reduced to 7W, with the iPhone’s battery reaching 70%, while the Realme’s battery was reduced to 61%.
Test Timeline: Start • at 30 minutes • end at 70 minutes
For comparison, in our review of the iPhone 17 Pro, we used the 45W Pixel AVS charger, which got to 70% in 30 minutes and fully charged in 1 hour 18 minutes. To be fair to the P4 power, most phones don’t even support AVS as an input and Realme advertises a maximum reverse charging power of 27W. According to our test equipment, both phones negotiated up to 9V and 3A over USB PD.
The results speak for themselves – Realme P4 Power can fully charge the iPhone 17 Pro once. Just looking at the battery capacity you would think it would be able to double this, but due to conversion losses it would be slightly less than that.
Realme P4 Power acts as a power bank
Either way, we think a 10-30 minute top-up is what most people will do. And it’s still impressive that even if you decide to charge your friend’s iPhone to 100%, there will still be plenty of juice left in the P4 Power for hours of gaming by the time you get back home.
Now, there’s also the question of how fast the Realme P4 Power charges – with 80W SuperVOOC charging, Realme says it can charge 0-50% in 36 minutes. Of course, this is something we’ll test ourselves.
