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Is there an app for iPhone and iPad that will indicate charge voltage and current? Is this information available to the user already by some means I am not aware of? And without jailbreaking or some other hack?

The problem is that there's a number of third party Lightning cables and USB chargers that may not do exactly what they claim on the box and it would be great to be able to verify the claims. Or there's the possibility that the box is long gone and there's a need to identify the capability of a cable or charger quickly. It would be nice to get some idea on what a cable or charger can do without setting up some lengthy and involved timing of how long it takes to do a recharge. It would also be nice to get some voltage and current data without some inline USB ammeter and voltmeter, as such meters can be easily misplaced when they are needed while an iPhone is always in my reach.

I found I can get some limited information about cables and chargers with my MacBook. I can connect a cable between my iPhone and MacBook and see what System Information reports as voltage and current being supplied to the iPhone. Because every USB port on an Apple computer is limited to 5 volts at 3 amps there's only three outcomes it tests. Plug in cable and System Information shows data and power connection, this means cable has power and data connection. Plug in cable, System Information shows nothing as if the cable is not connected, but iPhone is charging, means the cable has a power connection but no data connection. Plug in cable, System Information shows nothing, and iPhone is not charging, means the cable is just broken. I guess there is a fourth option. Plug in cable and it starts a fire, then everybody dies, and people are sad.

I can do something similar with USB power bricks. I can use a known good USB-C cable and plug USB power bricks into my MacBook and see what System Information reports about it. Like with the cable test this gives little more than a pass/fail. A MacBook doesn't "speak" USB-BC and so any such USB power brick will just show as providing 5 watts even if it is capable of more. With USB-PD power supplies it will show the power supplied but not the voltage. In many cases the power supplied indicates the voltage supplied. 12 watts or less means 5 volts. More than 45 watts means 20 volts. Other than that there can be some ambiguity on what the power supply is doing.

Searching the internet for an iPhone app that does what I'm looking for has proven difficult, perhaps as I don't know the right search terms. That is assuming an app that provides the functions I'm looking for exists.

An app for macOS, or some other OS for a laptop with USB-C, might be helpful. Such an app will not be much help in identifying USB-BC power supplies and cables but if there is something that can show what a USB-PD power supply is saying can be helpful. The goal is to identify cables and power supplies in order to see how they will act with iPhones and other Apple devices with Lightning ports. Something that can tell me what a USB-PD power supply can do is at least halfway to my goal.

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  • If my answer isn't useful to you, please edit your question to be more concise and precise. However, I think Coconut-battery should at least be somewhat to you.
    – X_841
    Feb 15, 2021 at 11:40

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The only thing I have found that consistently works is a USB-C power meter, such as this one from Satechi:

https://satechi.net/products/usb-c-power-meter?variant=31043692041

I have tested many combinations of chargers, adapters, etc. and this will give the correct information. I found that some combinations of chargers and adapters work differently with for example a MacBook Pro and an iPad Pro - so getting the reading off a MacBook Pro might not reflect what actually happens with an iPad for example. This has happened to me even though the iPad Pro on paper should support that same voltage/ampere - and probably does - but for some reason having an adapter in between the charger and the iPad Pro makes for a different scenario.

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I am trying to give you some ideas, however, answering this wall of text is hardly possible, since there are multiple questions and this is a rather broad topic.

  1. Coconut-battery: This Mac App will give you information about cycle counts and power supply on the Mac side. If you connect an iPhone/iPad you can also see their information. This will give you more info about connected wall plugs and batteries.
  2. Check your cables with a multimeter: Usually a cable either works or it doesn't (and usually it does not work if there is physical damage that you can see). However, you could check that in detail if you use a multimeter.
  3. Using iPhone/iPad/Mac cables/wall plugs interchangeably is no problem: Your device will draw the current it needs. This means, as long as the voltage is the same, you can use wall plugs interchangeably. E.g. I use my MBPs wall plug (87W, USB-C) sometimes to charge my iPad. Further, all wall plugs have small text on them, indicating the voltage and current they provide. E.g. my MBPs charger states:

Input: 100-240V ~ 1.5A 50-60HZ
Output: 20.2V--4.3A (USB PD) or 9V--3A (USB PD) or 5.2V--2.4A

I know that you mentioned you don't want to use a multimeter, however, for other readers this info/tip might be useful.

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  • " Coconut-battery " I tried this app and it provided no more information on chargers than Apple's System Information and it had a tendency to crash.
    – MacGuffin
    Feb 15, 2021 at 14:46
  • " I know that you mentioned you don't want to use a multimeter, however, for other readers this info/tip might be useful. " How is using a multimeter useful? The contacts on a Lightning and USB connectors are quite small making them difficult to measure with a multimeter. Also, without some guidance on what to look for the suggestion of using a multimeter is not answering the question.
    – MacGuffin
    Feb 15, 2021 at 14:50
  • " Further, all wall plugs have small text on them, indicating the voltage and current they provide. " Indeed the voltage and current they provide is often indicated on USB power bricks but that does not necessarily give any indication of how Apple devices will respond to them. A USB power brick from a third party may indicate 5 V @ 3 A supplied but unless the power brick adheres to USB-BC, USB-PD, or Apple's BrickId an iPhone will sink only 5 watts from it.
    – MacGuffin
    Feb 15, 2021 at 15:00
  • I See, my answer only scratched the surface of what you are trying to find out. Weird that coconut-battery is unstable, it has worked fine ever since for me. Also, I can't find the information about connected iOS devices and the history viewer in Apples system info - wouldn't that be something you are looking for? You are correct, multimeter measurements on that small scale aren't easy, but surely possible. Are you looking for advice on how to get the correct tools or not interested in multimeter measurements at all?
    – X_841
    Feb 15, 2021 at 15:39
  • " I See, my answer only scratched the surface of what you are trying to find out. " No, it appears you've gone on a tangent about battery health. The question is, to rephrase it a bit, how can I quickly and easily determine the capability of Lightning cables and USB power bricks used to charge iPhones? The rest of the text is not asking new questions but describing what has already been tried. I discovered I can get only so much information to this end from macOS applications. I believe I'd get further with an iPhone app.
    – MacGuffin
    Feb 15, 2021 at 16:30

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