The Realme P4 Power was unveiled earlier this week and its headline feature is its massive 10,001mAh battery. In press materials, Realme compares it to a typical 10,000mAh power bank and says that the phone is 43% thinner (it’s 9.08mm thick) and is 14% lighter (weighing 219g). That’s impressive, but can you actually use the P4 Power as a power bank? We decided to put it to the test.
Here’s the setup – we started with a fully-charged Realme P4 Power and a nearly-dead iPhone 17 Pro, which was sitting at just 7% battery. We connected the two with a USB C-to-C cable and a device that can measure the charge speed in real time.
Test start: 22W of power, iPhone at 7%
At the start, the Realme was sending 22W to the iPhone. Note that to reach maximum reverse charging speeds, the screen on the P4 Power has to be off (otherwise, it reserves power for its own operation).
10 minutes into the test, the charge speed fell slightly to 19W and the iPhone 17 Pro was already at 23%, while the Realme P4 Power still had 94% left in the tank. Check out our video here to see the reverse charging in action.
30 minutes after the start, the charge speed tapered off 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 would have enough for the rest of the day, job done.
But out of curiosity, we pushed on. After 50 minutes of charging, the iPhone had reached 65% (with charge power dropping further to 9W) and the Realme was at 70%. We ended the test after 70 minutes total – charging was down to 7W at that point, the iPhone’s battery had reached 70%, while the Realme’s battery was down to 61%.
Test timeline: start • 30 minutes in • end at 70 minutes
For comparison, in our review of the iPhone 17 Pro, we used a 45W Pixel AVS charger, which got to 70% in 30 minutes and did a full charge in 1 hour and 18 minutes. To be fair to the P4 Power, most phones don’t support AVS even as input and Realme advertises maximum reverse charging power of 27W. According to our test device, the two phones negotiated USB PD at 9V and up to 3A.
The results speak for themselves – the Realme P4 Power can fully charge an iPhone 17 Pro once. Looking at the battery capacities alone you’d think it will be able to do it twice, but due to conversion losse it will come just short of that.
The Realme P4 Power acting as a power bank
Either way, we think that a 10-30 minute top up is what most people would do. And it’s still impressive that even if you decided to charge your friend’s iPhone to 100%, you would still have plenty of juice left in the P4 Power for hours of gaming until you get back home.
Now, there’s also the question of how fast the Realme P4 Power itself charges up – with 80W SuperVOOC charging, Realme says that it can do 0-50% in 36 minutes. Of course, this is something that we will be testing ourselves.
