A teardown of Apple’s new $99 MagSafe Battery Pack from Charger Lab has given us our best look yet inside the new accessory, and revealed more details about how it works. For starters, it confirms recent speculation that it uses a pair of battery cells wired in series like Apple’s previous Smart Battery cases, but it also gives us a look at the NFC circuitry and heat shielding within.
A dual-cell design is important, because it allows the voltage of the battery pack to be higher than a comparable single-cell design. While each individual cell is labelled as being 3.82 volts, the overall voltage of the battery pack is 7.62 with them wired in series. It means the pack should be capable of supplying more power than its 1,460mAh capacity would suggest when compared directly with the battery capacities of the iPhone itself, with a total power output of 11.13Wh. AppleInsider has a good writeup of the science if you’re after more detail.
Beyond the battery cells, the teardown gives us a good look at how the battery pack dissipates heat. In February, when Bloomberg first reported the existence of the pack, it noted that development had been set back because the iPhone’s software kept thinking the accessory was overheating. It’s unclear if this problem was overcome with software or hardware fixes, but clearly a lot of effort has gone into keeping the pack cool while allowing it to supply enough power.
Unlike the right-to-repair advocates over at iFixit, Charger Lab doesn’t offer a repairability score at the end of its teardowns. But the amount of adhesive and concealed tabs holding the battery pack together don’t make it look very user serviceable. We’ll have more details on how it performs in practice in our forthcoming review.