The iPhone 15 may use electric car-style stacked batteries in all iPhone 15 models, Twitter leaker RGcloudS claims.

RGcloudS says that progress on this technology is "on track, but limited," and suggests that the same technology will be included in the Galaxy S24 Ultra and Plus models. This would seem to enable 65W charging for Samsung's 2024 flagship.

A stacked battery means higher battery density, meaning the iPhone will have more milliamp-hour capacity in the same battery area. For this reason, rumors suggest that there will be little size difference between the iPhone 15 series and the current iPhone 14 models, and that all iPhone 15s will have larger battery capacity at the same time.

There are two disadvantages to having a higher density battery. The iPhone is already notorious for getting warm under load, so hopefully this new stacked cell won't make it any worse. According to RGcloudS, at least the stacked batteries seem to have a low risk of exploding in the worst case scenario.

Another trade-off for high-density batteries is charging speed: one of the reasons the iPhone is one of the slowest charging phones on the market is that its battery is already much denser than its Android competitors. Further increasing this density would make it even less likely that Apple will adopt Samsung- or OnePlus-style fast charging for the iPhone 15 or future models.

That said, RGcloudS says Apple is testing iPhones with up to 40W wired charging and 20W MagSafe wireless charging. This could be an upgrade for the iPhone 16, they continue, possibly meaning that more work needs to be done on the new laminated cell design to release faster speeds than traditional high-density batteries can manage.

The iPhone 15 is said to be a further upgrade apart from the battery update. For the first time, a USB-C port will be used for charging, and the Dynamic Island notch is said to be on all models, not just the Pro. According to a tipster, the iPhone 15 Pro will add to this with a new A17 chipset, and the iPhone 15 Pro Max will take it a step further by adding a periscope telephoto camera for enhanced zoom.