Comparing iPhone 8 charging speeds with fast charge, wireless and more

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With the launch of iPhone 8 and 8 Plus, Apple introduced its smartphone user base to fast charge technology capable of delivering an up to 50 percent charge in just 30 minutes. AppleInsider takes a closer look at the technology and how it compares to traditional -- and wireless -- charging methods in this video.




In order to take advantage of the new fast charge feature, users will need a few extra pieces of hardware that don't come included in an iPhone 8 box.

First, a USB-C to Lightning Cable adapter that supports USB Power Delivery (USB-PD) is needed to connect an Apple 29-watt, 61W or 87W USB-C power adapter to your iPhone 8. Alternatively, third-party USB-C power adapters that support the same specification can also be used as a stand-in for Apple's branded accessories.

For our test, we'll be taking a look at Apple's 29W charger, the 12W adapter included with the latest iPad Pro models, the 7.5W Belkin Boost Up wireless charger marketed in Apple stores and the 5W adapter included with all iPhone 8 models. In addition, we also evaluated direct charging from an iMac using both a USB-C to Lightning cable and a USB-A to Lightning cable.

Before looking at the results, it should be noted that there is no material difference in charging speed between Apple's 29W and 87W USB-C chargers. If you're buying an Apple branded charger specifically to charge your iPhone, save some money and go with the 29W version.





The first step in our test involves depleting iPhone 8 Plus' battery until the device shut down. We then plugged the handset into the selection of adapters mentioned above and recorded onscreen battery charge indications at regular intervals.

After five minutes, the fast charging method involving Apple's 29W adapter takes an early lead with iPhone showing a 9 percent charge. Trailing behind at 7 percent charge is the 12W adapter, while USB-C from an iMac stands at 6 percent. The gratis 5W adapter manages an only 4 percent charge after the same 5 minute period.

At the 15 minute mark, the fast charger reached 29 percent, extending its lead over the 12W charger's 19 percent. Interestingly, the USB-C to iMac method followed close behind at this point with an 18 percent charge.

After 30 minutes, the USB-C fast charger exceeded its promised charging rate at 52 percent, while the 12W ended at 36 percent. Not a huge difference, but definitely noticeable. The USB-C to Lightning cable plugged into our iMac was just behind the 12W adapter with 34 percent charge, while the USB-A to iMac was slower at 26 percent.

The wireless charger and 5W adapter finished the 30 minute run with about 20 percent charge, less than half what USB-C can achieve.




Moving to one hour, our fast charger system gained an additional 28 percent over the ensuing half hour. It's clear Apple's power controller ratchets down charge rates after 30 minutes. Our 12W adapter and USB-C to iMac setup gained about 34 percent over the same time period, but still lagged behind in total charge. The wireless device and 5W adapter increased by 20 percent to end the hour at about 40 percent, while USB-C to lightning inched up from 27 percent to 53 percent.

It took an additional half hour, or one and a half hours total, for the fast charger to completely charge our iPhone 8 Plus. The 12W and USB-C to iMac connection needed only 15 minutes longer to top up.

Even though the included USB-A to Lighting cable plugged into our iMac was at first noticeably quicker than the 5W adapter, it started slowing down and finished only 10 minutes ahead.

Wireless charging is currently just as slow as the included 5W adapter, both charging at a consistent rate of about 10 percent every 15 minutes. In total, it took 2.5 hours to achieve a full charge on both 5W and wireless methods. This should come as no surprise, as iPhone 8 only accepts 5 watts of power when charging wirelessly. Apple plans to boost wireless charging speeds with a future software update, bringing power transfer rates up to 7.5W, the peak output of Belkin and Mophie chargers sold in the company's stores.

If you need the fastest charge possible, use the right USB-PD charger and cable, especially in the first half hour. That said, the same USB-C to Lightning cable plugged into an iMac or an iPad charger yields performance that isn't that far off from the standalone 29W adapter.

If you want slightly quicker speeds than the included 5W adapter, but don't want to spring for a separate accessory, plug that same cable into a USB 3.0 port on a Mac.

Finally, if you care about speed over convenience, you'll want to stay away from wireless chargers, at least until Apple updates its firmware.
kenc
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Comments

  • Reply 1 of 32
    Doesn't fast charging put stress on a lithium-ion battery?
  • Reply 2 of 32
    radarthekatradarthekat Posts: 2,125moderator
    Would love to this in table format across the full line-up of on-sale iPhones, from SE to X.  Obviously there‘d be some N/A entries in that table, but it’d be great to see them all compared.  I often plug my iPhone 6 into my iPad charger to get as much charge as popsicle when getting ready to head out the door.  It does charge noticeably faster, but I don’t know by how much.
    edited October 2017 mwhite
  • Reply 3 of 32
    Thanks for this article.  Will be interesting to see how the 7.5w wireless charger performs after the update that ‘unleashes’ it past charging at 5W.

    So a 12w brick is about $19, but the usb-c brick and usb-c to lightning cable combo comes out to $75 through Apple or $50 if you buy a 3rd party charger.  That’s a big price difference to get to a full charge 15 min sooner.
    netmage
  • Reply 4 of 32
    Doesn't fast charging put stress on a lithium-ion battery?
    A little about this would be just as interesting as the charge times. I’ve always heard slower/cooler is better on the battery.
  • Reply 5 of 32
    Anker's USB chargers with PowerIQ also charge the iPhone 8 at the faster speed of the Apple 29W adaptor.
  • Reply 6 of 32
    foggyhillfoggyhill Posts: 4,365member
    Leifur said:
    Doesn't fast charging put stress on a lithium-ion battery?
    A little about this would be just as interesting as the charge times. I’ve always heard slower/cooler is better on the battery.
    It certainly is, keeping current density and heat low is one of the key to battery life.
    Though that's less the case in the middle of the curve, between 20-70% than the extremity of the curve.
    Seems the charging algorythm try to slow down charging at both ends; over 70%, the charging rates for all methods are pretty close.

    That's undoubtedly why Apple still ships the Iphone with a 5w charger.
    edited October 2017 watto_cobra
  • Reply 7 of 32
    Since most users plugin only at night to recharge, the 5 Watt charger is perfectly fine—it’s not because Apple is cheap. Some plugin at work, and will find an hour or so on a 5 Watt will be enough to end the day with plenty of usage time remaining. 

    If you’re a heavy user with short recharge windows, the 12 Watt is a great option. It doesn’t seem to hurt the battery any, that’s what I’ve always used on my 6S and its capacity is still excellent at 1,500mAh after 2 years. (Personally, I try not to let my battery drop below 25% if I can help it.)
  • Reply 8 of 32
    foggyhillfoggyhill Posts: 4,365member
    Since most users plugin only at night to recharge, the 5 Watt charger is perfectly fine—it’s not because Apple is cheap. Some plugin at work, and will find an hour or so on a 5 Watt will be enough to end the day with plenty of usage time remaining. 

    If you’re a heavy user with short recharge windows, the 12 Watt is a great option. It doesn’t seem to hurt the battery any, that’s what I’ve always used on my 6S and its capacity is still excellent at 1,500mAh after 2 years. (Personally, I try not to let my battery drop below 25% if I can help it.)
    Not letting it drop low, or using the phone to do something heavy while plugged in, is the best thing for the battery.

    You can get 3 years of battery use before its at 70% of original charge doing that, easy.
    edited October 2017 pscooter63
  • Reply 9 of 32
    Interesting how closely the 7.5w wireless so closely matches the standard 5w charger.  Almost like it was originally designed that way.

    I love the 12w charger that came with my old ipad.
    edited October 2017
  • Reply 10 of 32
    k2kwk2kw Posts: 1,066member
    Fast charging isn't really that much faster.   Its like its more a dud than a feature.   Maybe this is what it takes to keep phones from exploding like the Note 7.   Would be need to compare with fast charging on Android phones.
  • Reply 11 of 32
    macxpressmacxpress Posts: 3,880member
    I just use an iPad charger on my iPhones...always have. Thats fast enough for me. Honestly, my phone easily lasts all day on a charge so I just let it recharge overnight while sleeping. Same goes for my Series 0 Apple Watch. 
    edited October 2017 watto_cobra
  • Reply 12 of 32
    macxpressmacxpress Posts: 3,880member
    k2kw said:
    Fast charging isn't really that much faster.   Its like its more a dud than a feature.   Maybe this is what it takes to keep phones from exploding like the Note 7.   Would be need to compare with fast charging on Android phones.
    I'm sure Apple did a lot of testing to make sure the fast charge feature wasn't a major hinderance into the performance of the battery. 
  • Reply 13 of 32
    The generic Qi charger I have seems to work very well, especially for the $10 it costs. I have it plugged into a 2.1A wall charger. 
    watto_cobra
  • Reply 14 of 32
    MplsPMplsP Posts: 317member
    Any more word on the iPhone battery failures that were recently reported and whether they were at all related to charging? I also wondered about battery stress with the fast charging.

    I also noted the near identical performance of the 7.5w wireless and 5w wired charging. The thing I notice is that switching to a wireless charging pad uses/wastes 50% more power than standard wired charging. Seems like a big step backwards for a pretty minor convenience. 
  • Reply 15 of 32
    A bit off topic, but I would love to know if Apple throttles any of it's charging based on the temperature of the device? 

    I've definitely been through warm situations (a week in Italy) where my battery seemed to fry itself.   (I generally always travel with a 12w charger), Have seen this with a 6, 6s, and 7+..  Theory is apple doesn't slow down charging speed based on the temp of the battery.  And this allows the battery to fry itself shortening it's lifespan..  

    Also not helping is any form of case holding heat in while charging.  

    Quick search shows 45C is a likely max battery temp during charging..  I've definitely had my phone exceed that...

    https://electronics.stackexchange.com/questions/262917/how-hot-can-a-lithium-ion-battery-safely-get-while-charging
  • Reply 16 of 32
    Mike WuertheleMike Wuerthele Posts: 1,929administrator
    MplsP said:
    Any more word on the iPhone battery failures that were recently reported and whether they were at all related to charging? I also wondered about battery stress with the fast charging.

    Not at present. Right now, they appear to be infant failures of some sort.
    watto_cobra
  • Reply 17 of 32
    avon b7avon b7 Posts: 1,825member
    A bit off topic, but I would love to know if Apple throttles any of it's charging based on the temperature of the device? 

    I've definitely been through warm situations (a week in Italy) where my battery seemed to fry itself.   (I generally always travel with a 12w charger), Have seen this with a 6, 6s, and 7+..  Theory is apple doesn't slow down charging speed based on the temp of the battery.  And this allows the battery to fry itself shortening it's lifespan..  

    Also not helping is any form of case holding heat in while charging.  

    Quick search shows 45C is a likely max battery temp during charging..  I've definitely had my phone exceed that...

    https://electronics.stackexchange.com/questions/262917/how-hot-can-a-lithium-ion-battery-safely-get-while-charging
    I would think the charging design caters for heat and effectively 'throttles' charging in the case of excessively high temps. Perhaps the tolerances are higher than you are comfortable with but probably within the safety limits.
  • Reply 18 of 32
    k2kwk2kw Posts: 1,066member
    Max,  can you run the same test for the iPadPro?
  • Reply 19 of 32
    GeorgeBMacGeorgeBMac Posts: 1,726member
    So will this fan the wars against non-Apple chargers -- or refute them?
    ... If the power coming through the cord no longer matters to the phone, why not buy that one from China?
  • Reply 20 of 32
    maestro64maestro64 Posts: 3,907member
    Doesn't fast charging put stress on a lithium-ion battery?

    That is why they turn it off one the battery hits 50%, it is the heat that kills batteries, Apple is monitoring the battery temp along with other things to ensure the battery is not stressed. Heat has always been bad for batteries even since NiCad and NiHi prior to the Li batteries. The issue today is Li battery when they fail does it will lots of energy. NiCad fail but not to excitingly, and NiHi only had issue if the batter back was seal and the Hydrogen built up in the pack.
    watto_cobra
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