An EU regulatory document uploaded by Apple confirms that the iPhone Duo packs a 4,883mAh battery. That’s larger than the battery in the iPhone 18 Pro, but smaller than the one in its Pro Max sibling.
Unlike other iPhones, the iPhone Duo features two separate cells: one 2962mAh and another 1921mAh.
Two cells make room for a bigger battery
The iPhone Duo’s foldable design means Apple had to get innovative to pack a battery inside the device. So, instead of using a single cell, it split the battery into two separate cells to maximize capacity, one in each half of the phone: a 2,962mAh cell and a smaller 1,921mAh cell (via MacRumors).
This is a considerably large battery, even compared to Samsung and Google foldables. The Galaxy Z Fold 8 Ultra packs a 5,000mAh battery, but that’s despite using silicon-carbon anode cells. Google’s foldable fares worse, packing a 4,806mAh battery.
The iPhone Duo’s 4,883mAh battery is bigger than the iPhone 16 Pro Max’s 4,685mAh cell.
With a large 7.6-inch internal screen, the big battery will help the iPhone Duo provide all-day battery life. While it may not match the iPhone 18 Pro and iPhone 18 Pro Max, it should still be sufficient to last through a regular workday.
Obviously, a lot will depend on whether you rely more on the inner folding screen or the smaller cover display.
A quick charge before you unfold and go
Despite the relatively big battery, Apple says the iPhone Duo can go from 0% to 50% in about 20 minutes with a compatible 60W power brick.
With a compatible MagSafe wireless charger, the foldable can hit 50% in 30 minutes. That’s just a wee bit slower than the iPhone 18 Pro’s fast charging speeds.
The fast charging speeds should be useful on days when you need to quickly top up the Duo to get a few more hours of runtime.
Rajesh has been writing about consumer technology for over a decade, with a strong focus on iPhones, Macs and Apple’s ecosystem. He enjoys digging into Apple software updates, hardware changes, and discovering new Mac apps that make work faster and more enjoyable.
You can reach out to him at mail[at]rajeshpandey.me.
