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Is it OK to use my iPhone charger for charging other USB powered devices like the Kindle or a digital camera (with a rechargeable battery)? Can it cause any damage to the charger or to the device being charged?

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related: apple.stackexchange.com/questions/2017/… – Cawas Feb 25 '11 at 19:43
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8 Answers

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Most standard USB charges for 0.5A. But not all USB are standardized - there are some that go for up to 1.8A and even the MacBook Pro is said to raise up to 1.1A when relevant. iPhone's charger do little more than 1.1A and it's pretty decent. That's why iPhone charging on regular USB usually take double the time to fully charge. iPad's charger are roughly 10W and 5V which translates to 2A.

There's nothing wrong that can happen with the charger because USB devices are made to work with the same standard voltage (about 5V). The USB hosts are only outputting the maximum energy it can provide up to what the client can receive. A 10W energy source will only give up to 10W and just 1W if the plugged device can only take 1W.

I'm no electrical specialist but...

Having bigger power supply (measured in watts) or bigger current (measured in amperes) on itself can't break any system because what puts them in movement is the difference of potential measured by volts.

Think of a light bulb and picture all USB devices are prepared to receive about 5V (actually little more). If you get a 220V and put in on a 110V nothing wrong happens, but it will be very weak. Apple's chargers only go up to 5V, which is within the USB standard. So yeah, it's all good and safe.

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The current/voltage comments regarding the iPad charger is incorrect. It supplies 5V @ 2A. The iPad internally converts the 5V to the 4.2V max required to charge the lithium batteries. Frankly, any device that has a USB connector, and supplies anything other then 5V is a fire hazard. – Fake Name Oct 26 '11 at 9:15
As a side note, I use my iPad charger to charge my (Android) phone regularly. It works fine. – Fake Name Oct 26 '11 at 9:16
@FakeName if you mean both 4V and 6V USB hosts are both fire hazards, that makes no sense to me. As for the iPad charger, I stand corrected. I'm not sure where I got the 3.7V figure from, but Apple sure gives a hard time publishing this data as I couldn't find any! – Cawas Oct 27 '11 at 0:26
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A USB host that supplies anything other then 5V is (significantly) out of spec, and not really a USB host anymore. A USB Host that supplies 6V is definitely a fire hazard. A USB host that supplies 4V could be dangerous, depending on how the connected device handles an undervoltage problem. It should be safe, but I'd rather not risk it. – Fake Name Oct 27 '11 at 7:02
Also, USB is standardised. On 500 mA (USB 3 is 900 mA). USB hosts that supply more current are violating the standard. Generally, the non-standard extensions used to allow higher charging currents are carefully designed to fall back to standard USB behaviour in the event that a standard USB device is connected. – Fake Name Oct 27 '11 at 7:05
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up vote 4 down vote

Yes, you can. It converts the AC power to the standard USB power, so anything that charges with USB will charge with the iPhone's adapter.

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up vote 1 down vote

Usually you can use the charger for other devices. But check the power requirements of the device in question. For instance an iPhone charger can't charge an iPad that's not sleeping (because it requires 10W and your iPhone charger is probably rated for 5W).

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actually iphone charger can charge an ipad much better than regular USB can. and both do it. but it's true they might not charge fast enough if the iPad is being used. – Cawas Feb 25 '11 at 20:10
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up vote 1 down vote

Regarding to USB charging, there are two kinds of USB devices:

  • Dumb ones that doesn't check if they are connected to a charger and always use less than 100 milliamperes. Some use up to 500mA, but they are out of USB specs.
  • Smart ones that check if they are connected to a charger and try to use full power of the charger (up to 1800mA or 2100mA).

Apple USB chargers (1000mA to 2100mA) are of the second type but doesn't follow the USB charging standard (1800mA) and aren't compatible with other smart devices that follow that standard. Only with dumb devices and other apple devices.

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up vote 0 down vote

I have a Nuvi nav system with a mini-USB charging/sync port. It hangs when plugged into a generic charger. My theory is that the nuvi gets confused for some reason and tries to go into sync mode when it should just charge. I don't know how the nuvi charger or cable is different than a generic USB charger or cable.

So caveat emptor. But I would expect that it usually works across devices.

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the Nuvi might be setup to work only with their gear. I hate it when companies do that... – Nathan Greenstein♦ Feb 24 '11 at 23:50
The nuvi is a general issue; only their car charger can tell it that it's not a computer. – SLaks Feb 25 '11 at 3:32
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up vote 0 down vote

My brother charged his Blackberry just great using his USB cable and my iPhone prongs-to-USB wall cube.

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up vote 0 down vote

There is no doubt that you can't because iPhone charger is not even the same as iPad charger. The full info about this you can read here

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There seems to be some doubt that you can't, actually: see also all the other answers to this question. – Dan J Feb 7 at 18:23
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up vote 0 down vote

Be careful. I tried charging a Kindle Fire with my Apple iPhone chargers and ended up burning out 2 of them.

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