Battery figures reported by Android Authority on October 19, 2026 point in different directions: iPhone Duo has a longer EU energy-label endurance rating per charge, while Galaxy Z Fold 8 has more rated cycles before its battery reaches 80% capacity. Multiplying those ratings gives 51,500 label-hours for iPhone Duo and 59,000 for Galaxy Z Fold 8, but those totals are calculations, not observed device lifetimes.
For broader context on the foldable, see NeoTeo’s earlier report on its release timing.
Capacity figures use different labels
9to5Mac reports that iPhone Duo’s battery combines two cells, 2,962 mAh and 1,921 mAh, for a reported total of 4,883 mAh. Android Authority reports Galaxy Z Fold 8 at 4,660 mAh rated capacity and 4,800 mAh typical capacity. The Duo’s total and the Fold 8’s rated and typical figures are not a like-for-like capacity comparison.
Per-charge endurance and cycle rating
Android Authority reports these two energy-label measures for the phones:
| Battery metric | iPhone Duo | Galaxy Z Fold 8 |
| Endurance per charge | 51 hours 30 minutes | 49 hours 10 minutes |
| Rated cycles before capacity reaches 80% | 1,000 | 1,200 |
The reported endurance rating is 2 hours 20 minutes higher for iPhone Duo. Galaxy Z Fold 8 has 200 more rated cycles before reaching the 80% capacity threshold. One measure describes endurance per charge; the other counts cycles to that threshold, so neither settles the question of everyday runtime on its own.
What the combined calculation says
Converting 51 hours 30 minutes to 51.5 hours, then multiplying by 1,000 cycles, gives 51,500 label-hours for iPhone Duo. For Galaxy Z Fold 8, 49 hours 10 minutes is 49⅙ hours; multiplied by 1,200 cycles, that gives 59,000 label-hours. The difference is 7,500 hours, or about 14.6% of iPhone Duo’s calculated total.
That arithmetic combines two reported label ratings. It is not an observed operating lifetime or a prediction of how long either phone will last for an individual owner.
iPhone Duo’s video-playback estimates
Separately, 9to5Mac reports Apple video-playback estimates of 44 hours on iPhone Duo’s outer display and 31 hours on its inner display. Those estimates describe video playback, a different measure from the energy-label endurance ratings.
