Today, a charger is a full-fledged computer with more processing power than the Apollo 11 spacecraft that brought humans to the Moon. Before the charging adapter starts pumping the voltage, it must first communicate with the smartphone. Incompatibility of the communication software protocol is the reason why a smartphone with USB PD, for example, cannot fast charge from a VOOC charger.

Read on technical details of fast charging technologies. Find out why the best charger – is your old feature phone's charger.

I don't think Apple was the first to use the magnets to align the phone to the charger. I think I had a nexus 5 that had the magnets in the phone and google Qi charger -- that would perfectly align the phone and charger.

>In such a situation, the best solution is slow charging, for which a low-power charger from your old feature phone is ideal.

It seems like most Android phones now have a feature that does this, though you have to enable it. Mine asked me to put in the time I go to bed and the time I wake up, and it slowly charges the battery over that time period to 100%

I feel something is missing at the moment with our ability to choose on the device how I want it to charge. Would be nice to plug the phone in and unless I say otherwise it does a nice slow charge even if the cable and charger is capable of more. But if I press a button on the front after I plug it in then I can select fast and it goes as quickly as the combination allows. Its irritating to have to have different chargers for this to preserve the battery.

Its pretty bad that only recent phones have started to add the ability to charge to only 80% to keep the battery in the optimal zone to extend the life given how long we have known that 80% was the optimal maximum. There are also a few phones now able to power themselves from USB without using the battery which if you leave them in chargers a lot throughout the day and night seems like a good feature to have to preserve the battery further.

Maybe all the complexity around this is too much and people just want to plug it in and quick 100% as quick as possible and will change their phone regularly but its pretty wasteful. We ended up going through lots of special chargers that all do very similar things and now you get a device and it often doesn't even come with a cable let alone a charger and you are digging through the specs of your charger, cable and device to work out if its all going to mesh correctly together or you'll be stuck on slow mode. We have ended up with so many standards for getting quicker than the basic charge its going to take a while for all these devices to age out and in the meantime chargers are going to be doing QC and PD and a host of other things besides for a while.

It is annoying that while the connector itself is now finally standardized, the details of implementation diverge. So while you may be able to charge, it'll be slow charge.

Many phones/chargers with propietary protocols are also equipped with USB PD compatibility. For example, you can pick up some random Xiaomi phone labelled at 90W and expect it to charge at more than 20W with USB PD, or even ~90W on some vivo models.

I don't see why the best charger is the old feature phone's charger - the point in fast charging is that you don't have to wait too long if in a hurry. That charger is the "best" if only you have almost unlimited time to charge, like during the night.

Wish they’d kept 12V throughout the PD standards. So useful for hobby stuff

One thing I was hoping the article would explain is how fast charging actually works: IE, how does the charge controller turn incoming electricity into a full battery?

The reason why I switched to wireless charging was because I had a phone go bad due to problems with the charge port. USB-c ports on my Pixels to tend to clog with dust and other debris, but as long as I use a wireless charger, it doesn't matter.

> the best solution is slow charging, for which a low-power charger from your old feature phone is ideal. These devices offer a small power output of 2–5 W, stretching the charging process to 5–7 hours depending on the adapter's power and the battery capacity. This way, your phone's battery charges under the best conditions, minimizing degradation

I've been charging my iPhone this way since the iPhone 4 (trickle charging overnight) and have noticed zero improvement in battery degradation performance vs. fast charging.

As a current example, my iPhone 15 Pro, purchased a month after launch, is at 85% capacity.

Unfortunately I’m not sure this article is good, as it doesn’t seem technically sound.

Disclaimer, I was expecting an article with such a title to talk more about silicon anode batteries, or perhaps LTO (lithium titanate oxide) batteries that can charge in about 6 minutes (10C). It’s fine that the article doesn’t talk about that… however some of its other claims are a bit problematic.

> In such a situation, the best solution is slow charging, for which a low-power charger from your old feature phone is ideal. These devices offer a small power output of 2–5 W, stretching the charging process to 5–7 hours depending on the adapter's power and the battery capacity. This way, your phone's battery charges under the best conditions, minimizing degradation. Fast charging leads to up to 1.6% battery degradation every 100 days, according to an experiment comparing 5W and 25W charging on six identical smartphone batteries.

Sorry but that’s not the correct conclusion (or advice). Fast charging to 80% at cool temperatures will give a much better lifespan than charging slowly to 100% in a warm room. The issue isn’t charging speed, it’s the heat, along with time of strain (at high SOC). In fact there are pulsed very high speed charging patterns under testing that show even lesser dendrite formation than standard charging.

For anyone wanting to learn more, I highly recommend battery university. They’re probably the best resource out there on the net for genera purpose info on lithium batteries.