How fast can you charge an iPhone?

An iPhone 8, now a relatively cheap model, can fully charge its battery in two hours. Faster charging is almost never necessary, but the question is fair: how much faster can it really go? [Scotty Allen] from [Strange Parts]back after a hiatus, is back to pushing the boundaries of what a regular iPhone can do, and decides to start exploring battery technologies.

What people often encounter is that the charging speed depends on the particular charger, but even a hundred chargers in parallel will not speed up the charging speed of this iPhone, so what’s going on? First, the phone’s charger chip and the battery’s BMS will both limit charging current, so those had to be bypassed for experimental purposes. The first attempt was using a hefty DC power supply with the original cell, and dissatisfied with the lack of fire and still relatively slow charging, [Scotty] decided to raise the bar.

There are a few battery technologies you can pair with a phone if you want to dramatically speed up charging, and [Scotty] show one of them in action – lithium titanate batteries, for example, can take quite a beating when it comes to charging current, and they’ve helped cut charge time to 22 minutes. That’s no match for a supercapacitor package, though, which cuts charge time down to nine minutes – a thirteenfold increase over the 90 minutes we’d expect. We may not have a supercap-based iPhone anytime soon, but now we’ve definitely seen one.

Facing this demo, Apple should be ashamed of their Lightning charging ports. Perhaps, with a few hobbyist supercapacitor tricks in hand, supercapacitors will come in handy for one’s statistically unavoidable project where charging time will be of paramount importance. Until then, we will likely continue to focus our efforts on building power banks.