I completely switched to flexible chargers from fast and now feel safe

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Highlights taken by ZDNET

• Adaptive charging aims to reduce battery wear by keeping the charging speed low.
• Anker Nano 45W is the best flexible charger available.
• You can get many benefits by using a low power charger to charge at night.

Whether you use a cheap $10 charger or something much more expensive, the modern USB charger is an amazing little piece of technology. It may look like a box connected to the wall with a cable to another box. But behind the scenes, a lot is going on.

The moment you connect the charger to your device — whether it’s a smartphone, tablet, laptop, or power bank — the charger wakes up, and the two gadgets quickly negotiate the best and safest voltage and current combination to use before continuing to charge. Then, both the charger and the device being charged continuously monitor voltage, current, and temperature to ensure that charging is safe and that nothing explodes or catches fire.

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Gone are the days when a charger just pushes as much power to a device as possible.

When the gadget is close to being fully charged, the charger lowers the voltage until the battery is full, at which point charging stops.

And if a malfunction causes an overcurrent or overvoltage spike, or a short circuit in a cable or device, the charger kicks in and cuts off power.

But what if chargers could be even smarter?

This is where smart chargers come into play. Like most new technologies, this technology goes by different names. Anker calls it Care Mode, while other manufacturers use “smart” charging, “intelligent guidance,” and sometimes “AI” for good measure. Different names for the same thing.

What is dynamic charging?

In the last few years, the USB charger power output has exploded (pun intended). Back when you only got half an amp from a USB-A charger, we needed all the power the charger could muster. But now that chargers can handle 140W or more without breaking a sweat, that power needs to be regulated.

In a perfect world, you need a quick charge to bring the device from low to about 20%, a steady charge to bulk charge to 80%, and then switch the charger to trickle charge at 20%.

Ideally, you can also look for a way to turn off this feature if you want to charge a lot of the device very quickly.

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This is exactly what variable chargers do. The charger communicates with the phone being charged, the two negotiate the best way to charge, and the phone goes through different charging stages. The Anker Nano 45W will start at 45W output before dropping down to 20 to 30W for a full charge, then dropping all the way down to 10W for final output.

This is the most convenient way to charge a device like a smartphone and keep the battery in the best possible condition, and it is the ideal charging protocol when the phone is connected to the charger overnight or for a long time.

Does variable charging work?

At first I was skeptical about flexible chargers. After all, basic charging protocols like Power Delivery do a good job of keeping things safe, and almost every charger now supports it. And I have seen many speeches in my time, so I know that talk is cheap.

However, based on the tests I’ve done, monitoring power draw and temperatures, I’ve seen a significant drop in both overall charger and device temperatures (about 25°F and 6°F, respectively), which is great when it comes to the longevity of a modern smartphone.

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But (yes, there’s always a but): Dynamic energy doesn’t break or even bend the laws of physics. The only way you can get less heat when charging is to reduce the output, and this, will increase charging times.

Does it work with every device?

Fully adaptive charging, like Anker’s Care Mode, doesn’t work for all phones. In fact, I only saw support for the iPhone 17, 16, and 15 series, as well as iPad Pro models from 2020. This is because the charger needs to know which device it is charging, and so far, the number of devices that can do this is limited.

This is a major limitation. However, considering how many hundreds of millions of iPhones support this type of charging, and the fact that other companies are working to add more support to smartphones, things look good for the future.

Don’t want to buy a new charger with flexible features? I suggest you use a low power charger to charge at night — something in the 20W range it’s perfect for this — and keep your quick chargers for day-to-day charging with larger items like laptops and power banks.

Do you need it?

This question is sure to generate debate.

Finally, how fast the battery charges is controlled by its BMS (battery management system). One might argue to push all the power the charger allows to the device and let the BMS decide how much the battery gets. Fair point, but given how hot modern phones are, I’m not sure this is the best idea when it comes to longevity. Heat and overcharging are, after all, major contributors to battery wear, and anything you can do to reduce this should get you more out of your battery.

And when modern smartphones can cost $1,000 and more, this is not a bad thing.

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However, if you’re worried about overheating while charging, you can always take a different approach and invest in a wireless charger with built-in cooling, such as Anker MagSafe 3-in-1 charging station. This unit did an amazing job of cooling my iPhone.

What should you buy?

The best option for a flexible charger is this Anker Nano 45W. It’s cheap — $29 — and its modest power output makes it worth charging overnight. This model has a TUV-Certified Maintenance Mode that handles that initial fast charge well, then switches to a low-power mode for a bunch of charging, before finally dropping down to a charging mode.

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I Green Uno 100W another good choice. This one doesn’t have the same three switch modes, but it does a pretty good job of switching to trickle mode when the bulk of the charge is done.