Foldable phones now last all day, and Apple's first one tops the tests

Foldable phones used to be known for weak batteries. CNET's latest lab tests suggest that is changing. Apple's first foldable, the $1,999 iPhone Duo, had the best average battery score among book-style foldables. Among flip phones, the cheapest model tested, the $800 Motorola Razr, came out on top.

Why foldables struggled

Foldables have a lot working against them. They have huge screens, a hinge that takes up space and little room to shed heat. Two things helped recently. Some new models use silicon-carbon batteries, which pack more energy into the same space. Newer chips also use less power.

How the book-style phones did

CNET tested five: the Samsung Galaxy Z Fold 8 and Z Fold 8 Ultra, the Motorola Razr Fold, the Google Pixel 11 Pro Fold and the iPhone Duo. All tests ran on the inner screen, from a full charge, on Wi-Fi.

• Endurance test (45 minutes of video, social media, a game and a video call): the iPhone Duo finished with 99% left.
• Streaming test (3 hours of video): the Duo ended with 84%, just below the Razr Fold and both Samsung phones.
• The Razr Fold has a 6,000-mAh silicon-carbon battery and placed just behind the Duo.

The mAh figure (milliamp-hours) is a measure of battery size. CNET credits the Duo's result to its dual-cell battery and its A20 Pro chip. Its battery is 4,883 mAh, smaller than the Razr Fold's.

Thin phones held up

The Galaxy Z Fold 8 just edged the Z Fold 8 Ultra. Both are the thinnest in the group. The Z Fold 8 is 4.5mm thick open and 9.7mm closed. The Ultra is 4.1mm open and 8.9mm closed. The Pixel 11 Pro Fold was close behind.

Most of these phones did better in the endurance test than in the streaming test. That suggests they handle short bursts of use well but lose more power during long stretches like video streaming. CNET still says all five should get through a full day of mixed use.

The flip phone surprise

Flip phones have less room for a battery. Even so, the baseline Razr, with a 4,800-mAh battery, got the best average score among them. It also had the top result in the streaming test among its peers. In the endurance test it tied with the much pricier $1,500 Razr Ultra.

The other flip phones were the $1,100 Razr Plus (4,500 mAh), the Razr Ultra (5,000 mAh) and the $1,200 Galaxy Z Flip 8 (4,300 mAh). All use silicon-carbon batteries.

What it means for buyers

Battery life is no longer a strong reason to skip a foldable. Price does not predict battery results either, as the $800 Razr showed. CNET notes foldables are still a niche category, and its individual reviews cover everyday use in more detail.