An iPhone 8, now a relatively cheap model, can charge its battery fully in two hours’ time. There’s hardly ever a need for faster charging, but it’s fair to ask – how much faster could it really go? [Scotty Allen] from [Strange Parts], back after a hiatus, is back to stretching the limits of what a regular iPhone can do, and decides to start off with an exploration of battery technologies.
What people commonly encounter is that charging speed depends on the charger involved, but even one hundred chargers in parallel won’t speed up this iPhone’s charging rate, so what’s up? First off, the phone’s charger chip and the battery’s BMS will both limit charging current, so for experiment purposes, those had to be bypassed. First attempt was using a hefty DC power supply with the original cell, and, unsatisfied with the lack of fire and still relatively slow charging, [Scotty] decides to up the ante.
There’s a few battery technologies you could pair with a phone if your aim is to speed up charging dramatically, and [Scotty] demonstrates one of them in action – for instance, Lithium-titanate batteries can take quite a pounding when it comes to charging current, and they’ve helped get the charging time down to 22 minutes. However, that’s no match for a supercapacitor pack, which the charging time down to nine minutes – a thirteenfold increase from the 90 minutes we expect. We might not hold a supercap-based iPhone anytime soon, but now, we sure have seen one.
Facing this demo, Apple ought to be ashamed of their Lightning charging ports. Perhaps, with a few hobbyist-friendly supercapacitor tricks in hand, supercapacitors will be handy for someone’s statistically inevitable project where charging time will be of major importance. Until then, we’ll probably keep focusing our efforts on building powerbanks.