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Is it better to fast charge or slow charge iPhone?

With modern smartphones like the iPhone, charging speed is an important consideration. iPhones now support fast charging, which can charge your phone much more quickly than traditional slow charging. However, there are tradeoffs to consider between fast charging and slow charging your iPhone’s battery.

What is fast charging?

Fast charging uses higher wattage chargers and charging cables to deliver more power to your iPhone’s battery, charging it more quickly. For example, Apple’s 20W USB-C power adapter can provide a 50% charge in 30 minutes to newer iPhones that support fast charging.

The key things needed for fast charging are:

  • A phone that supports fast charging. Newer iPhones like the iPhone 8 and later support fast charging.
  • A compatible higher wattage power adapter. Apple’s 20W, 30W or higher USB-C adapters allow for fast charging.
  • A USB-C to Lightning cable. The cable is needed to deliver the higher power levels.

With those three things, you can fast charge newer iPhone models and achieve a 50% charge in 30 minutes or less in most cases.

What is slow charging?

Slow charging uses lower wattage chargers and cables. For example, the 5W power adapter that comes with iPhones charges at slower speeds.

With the 5W charger, an iPhone charges at about 10% per 30 minutes. So a full charge from 0 to 100% would take about 2.5 hours.

Slow charging subjects the iPhone battery to less power and heat during charging. This may help extend the battery’s lifespan over time.

Should you fast charge or slow charge your iPhone?

There are good reasons for both fast charging and slow charging your iPhone depending on your needs and priorities:

Fast Charging Slow Charging
  • Charges your iPhone battery more quickly
  • Great when you need to top up your charge in a hurry
  • Allows you to spend less time charging overall
  • Puts less heat and strain on the battery over time
  • May extend your battery’s lifespan
  • Great for overnight charging
  • Doesn’t require special cables or adapters

So in summary, fast charging is ideal when you need to charge quickly, while slow charging is better for battery longevity over years of use.

Does fast charging damage the iPhone battery?

Fast charging does not directly damage the iPhone battery, but it can lead to faster battery degradation over time compared to slow charging.

The key things that impact battery lifespan are:

  • High heat – Exposure to high temperatures during charging speeds up chemical aging reactions inside the battery, shortening its lifespan. Fast charging can cause more internal heat buildup compared to slow charging.
  • High voltage – High voltage places more strain on the battery components. The higher power delivery of fast charging applies more voltage stress.
  • Full charge cycles – Going from empty to full over and over degrades battery capacity. Fast charging tends to result in more full charge cycles since it empties the battery quicker.

However, it’s important to note that modern iPhone batteries are designed to handle some fast charging. Apple says the iPhone battery is designed for 500 full charge cycles before reaching 80% capacity.

So moderate use of fast charging will not immediately damage your battery. But relying exclusively on fast charging for years may degrade the battery slightly faster than slow charging in the long run.

Tips for maximizing iPhone battery lifespan

Here are some tips to get the most out of your iPhone battery when using fast charging:

  • Avoid charging to 100% whenever possible – Charge to around 80% for daily use to reduce strain.
  • Don’t let the battery drain below 20% too often – Shallow discharges prolong battery life.
  • Use slow chargers when you can – Like overnight charging.
  • Avoid exposing phone to high heat during charging.
  • Replace the battery after 500 full charges or when capacity drops.

Following those tips will minimize any extra battery wear caused by fast charging. Modern iPhone batteries can handle normal fast charging without too much downgrade in capacity for most users.

What iPhone models support fast charging?

Here are the iPhone models that support fast charging:

iPhone Model Fast Charging Support
iPhone 8/8 Plus Yes
iPhone X Yes
iPhone XS/XS Max Yes
iPhone XR Yes
iPhone 11/11 Pro Yes
iPhone 12/13 Yes
iPhone SE 2nd gen Yes

So in summary, the iPhone 8 and later support fast charging capabilities. Older models like the iPhone 7 and below only support standard slow charging.

Do you need a special charger for fast charging?

To fast charge your iPhone, you need a compatible higher wattage USB-C Power Delivery charger. The higher wattage chargers provide the extra power needed for fast charging.

Apple’s 20W, 30W or higher USB-C power adapters will support fast iPhone charging. Third party adapters that provide at least 18W power delivery also work.

You also need a USB-C to Lightning cable rather than the standard USB-A to Lightning cable. The USB-C cables provide the throughput needed for fast charging power delivery.

So in summary, you need both a compatible high wattage USB-C PD charger and USB-C to Lightning cable to fast charge your iPhone. The standard 5W charger and cable that come with iPhones will only slow charge.

Should you buy an official Apple fast charger?

Apple makes some great first-party fast chargers, but you can also find good third party options:

Apple Charger Third Party Charger
  • Guaranteed Apple quality
  • Seamless compatibility
  • Higher price
  • Often better value
  • Can lack compatibility
  • Lower price

Apple’s 20W and 30W USB-C adapters are good picks if you want peace of mind. But cheaper adapters from Anker, Aukey and others work well too.

One advantage of third party chargers is that higher wattage options are available for faster charging. For example, some offer 60W+ output compared to Apple’s 30W maximum charger.

How to tell if fast charging is working?

Here are some ways to confirm your iPhone is actually fast charging:

  • Use a fast charge capable wall adapter and USB-C to Lightning cable
  • Charging animation shows a lightning bolt icon
  • Battery percentage goes up quickly, around 50% in 30 mins
  • Device feels warm to the touch during charging
  • Charging speeds slow down above 80% as charging completes

As long as you see those indicators, you can be confident your iPhone is fast charging rather than slow charging.

Does wireless charging support fast charging?

The fastest wireless charging supported by iPhones is 7.5W. This is slower than the fast charging rates possible with wired charging which can reach 20W+.

Wireless charging works by transferring power between charging coils in the wireless charger and iPhone. This method has lower power efficiency compared to a direct wired connection.

Early iPhones only supported 5W wireless charging. Later models increased the charging rate to 7.5W, delivering a small boost. But wired fast charging remains much quicker for now.

The upcoming MagSafe standard promises faster 15W wireless charging. But even MagSafe won’t match the speeds possible with wired fast charging.

Should you disable fast charging at night?

It can be a good idea to disable fast charging when charging overnight or when your iPhone does not need to be charged quickly:

  • Use the standard 5W charger and USB-A to Lightning cable.
  • This will slow charge your iPhone, putting less strain on the battery.
  • Slower overnight charging generates less heat in the battery.
  • Helps prolong your battery’s lifespan in the long run.

Just remember to use a faster charger and cable when you need quicker charging. The best approach is to slow charge when possible and fast charge when you need it.

Other ways to prolong iPhone battery life

Aside from slow charging, other ways to maximize your iPhone battery lifespan include:

  • Avoid exposing iPhone to excessive heat or cold.
  • Don’t drain the battery fully to 0% too often.
  • Use low power mode to reduce performance and save power.
  • Turn off background app refresh if you don’t need it.
  • Disable unnecessary push notifications.
  • Reduce screen brightness when possible.

Combining those battery best practices with a mix of fast and slow charging will keep your iPhone battery in good shape for years.

Does fast charging reduce iPhone battery capacity?

Fast charging does not directly reduce your iPhone’s battery capacity. However, over years of use, relying solely on fast charging may degrade battery capacity a little faster compared to exclusively slow charging.

But the difference in battery lifespan between fast and slow charging over an iPhone’s usable life is fairly small. You would need to exclusively fast charge for years before noticing a significant drop in battery capacity relative to slow charging.

One study by Battery University found that after 500 full charge cycles, a battery lost 6% more capacity when fast charged compared to slow charged. But 6% less capacity after 500 cycles is unlikely to be noticed by most users.

So in summary, fast charging does not directly reduce battery capacity, but can lead to slightly faster degradation when used exclusively long term. But the difference is small enough that most users don’t need to worry.

Does the type of charger affect battery health?

The type of charger used does impact iPhone battery health in a few ways:

  • Higher wattage fast chargers degrade batteries faster – The higher voltages and power delivery puts more strain on the battery through increased heat and electrochemical damage over time.
  • Lower quality chargers can damage battery – Cheap knockoff chargers often don’t provide steady power delivery or overcharge protection, leading to battery damage.
  • Old worn out chargers can affect battery life – Old degrading chargers may provide inconsistent power delivery, which strains the battery.

To maximize your iPhone battery’s lifespan:

  • Use Apple’s own chargers or high quality third party options.
  • Avoid cheap low quality chargers.
  • Replace aging chargers after years of use.

Using Apple or other high-end fast chargers minimizes damage, while cheap chargers can degrade your battery faster.


In conclusion:

  • Fast charging allows you to charge your iPhone battery more quickly, while slow charging is better for long term battery health.
  • Using a mix of fast and slow charging is ideal – fast charge when you need a quick boost, and slow charge the rest of the time.
  • Exclusively fast charging does reduce iPhone battery lifespan slightly faster, but the difference is small over the typical useful life of the phone.
  • To maximize battery health, also avoid fully draining or overcharging the battery, expose it to less heat, and follow other best practices.

Fast charging is very convenient and most iPhone owners don’t need to worry about minor battery degradation. But being mindful of when to slow charge can help prolong your battery lifespan even further.