I have an iPhone 13 Mini which has a weird charging behavior. If I connect it to my MBP or Mac Studio it fast charges as I would expect. But if I connect to my Apple USB-C charger (I mean this one EU version of this: USB-C power supply) or if I connect it to my work Dell XPS it can take up to four hours before it is fully charged.

Any ideas why this is happening? I had the understanding that the USB-C power supply at least should be able to fast charge the iPhone?

I have checked the battery health and it is fine and tried multiple adapters.

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    Have you tried different cables? Higher charging power needs to be negotiated with a charging device, otherwise for safety's sake it will only output the nominal USB 500mA.
    – Tetsujin
    Aug 1, 2022 at 9:15
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    Different cables and power supplies Aug 1, 2022 at 9:24

2 Answers 2


You probably have a bad Power Adapter, and the connector on your Dell XPS is slow.

I would recommend trying charging your phone from a different Power Adapter, that should solve the problem.

  • Already tried different power adapters will update the question accordingly Aug 1, 2022 at 8:16
  • @Lars Nielsen Maybe you have too much dust/dirt in your charging port? (it happened to me and my phone would charge very slow until I went to the Apple store where they thoroughly cleaned it for me for free). You can clean it yourself using some compressed air. Also, your charging port may be defective/broken in some way, might have to be replaced if no solution is working for you.
    – mpp
    Aug 2, 2022 at 6:26
  • @mpp but why would it work with the macs then ? Aug 2, 2022 at 6:33
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    @LarsNielsen I think I understand your issue now. It may be a variety of things, such as faulty outlets, old outlets, dusty outlets, etc. Also, I have heard that dell XPS ports do not output as much wattage/limit wattage when something plugged in is draining a large amount of power. However, I don't think Macs have this behavior from what I've experienced so that's why it's much faster on Macs. The wattage must be posted online somewhere, but when I was researching I wasn't able to find exact specifications. Have you tried using outlets in different locations (house, restaurant, public, etc.)?
    – mpp
    Aug 2, 2022 at 6:44
  • @mpp yup both at home, work, at my parents, at friends Aug 2, 2022 at 8:38

There’s four different means by which an iPhone and charger can communicate, USB-PD, USB-BC, “old school” USB, and Apple’s own BrickID. Each standard has it’s own limits and quirks.

Plugging an iPhone into an Apple 20 watt USB-C charger should be just as good or better than plugging into an Apple computer with a USB-C port. Apple specs show that most any Apple computer with USB-C will be able to supply 15 watts from it’s USB-C port. Connecting an Apple to an Apple should mean they talk all the same languages. With 15 vs. 20 watts you may not even notice a difference in charging time, at that point the Lightning port may be the limiting factor. Apple won’t say exactly how much power Lightning supports but testing shows it is likely 18 watts, or at least that is my recollection. Getting a bigger power supply than what Lightning supports won’t charge the iPhone any faster. A bigger power supply could actually charge slower than a “medium sized” power supply for reasons that get very technical very quickly, reasons that I’m not sure we need to go into.

It would not surprise me to see a 3rd party charger or computer charge an iPhone slowly as that could be explained by the devices not speaking the same language. Without support for iPhone “fast charging” any charging device would fall back to the “old school” USB spec of 5 watts (or is it 4.5 watts? I forget and it’s a tiny difference regardless) which would make the charging easily 3 or 4 times longer.

My first suspicion would be that the power supply is damaged but it sounds like this may have been ruled out. If that’s not the problem then perhaps the iPhone is somehow damaged. The iPhone may have a bad wire in it somewhere or a software problem preventing communication with the power brick. When any USB device is plugged in it goes into “old school” mode for backward compatibility, once the iPhone and charger communicate their capability properly then and only then should more power flow. If more power flows than the communication allows then we tend to see things damaged and potentially people hurt.

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    At work we have tried with an iPhone 11, 12, and 13 (mini and standard), a Dell XPS 13" and three different Dell XPS 15" where one was a different model than the two others. We could reproduce it across all three laptops and all the phones. Dell XPS simply charges the phone slow... Fun fact we could reproduce for some Samsung Galaxies as well. Oct 17, 2022 at 6:42
  • I like to see that you are testing different things to sort out the most likely cause. I’ll see USB-C ports on computers and docks that are not quite up to spec and so will show the behavior you describe of inadequate power being supplied. USB-C ports should provide 7.5 W minimum and not all manufacturers will meet that spec. Even with Apple specifying up to 15 W by USB-C there’s conditions on that, such as other devices drawing power from other ports. Science is playing around while writing it down. Be scientific about this and you should figure it out.
    – MacGuffin
    Oct 17, 2022 at 15:05
  • i am just surprised a high-end laptop like a Dell XPS cannot handle this. It is kind of a deal breaker for me. Oct 18, 2022 at 5:52

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