Using your iPad charger with other devices
Ask iLounge offers readers the opportunity to get answers to their iPod-, iPhone-, iPad-, iTunes-, or Apple TV-related questions from a member of the iLounge editorial team. We'll answer several questions here each week, and of course, you can always get help with more immediate concerns from the iLounge Discussion Forums. Submit your questions for consideration using our Ask iLounge Submit Form. We reserve the right to edit questions for grammar, spelling, and length.
Q: Can I use the iPad power adapter to charge my first-generation iPod touch and second-generation iPod shuffle? I know it is only designed for iPads. Thanks for your help.
A: The short answer is yes. The rule of thumb when dealing with DC power adapters is to ensure that the polarity and voltage matches and that the adapter can supply at least as much current as the electronic device requires. Incorrect voltage or mismatched polarity can damage an electronic device; insufficient current will only result in insufficient power to operate or charge the device.
However, all USB power sources provide 5 volts regardless of whether they are ports on your computer or AC chargers, and both the USB port and Dock Connector are standardized in terms of polarity and can only be plugged in one way. Therefore, your iPad, iPhone and iPod models all use the same voltage and the iPad and iPod adapters supply the same voltage, as do your computer’s USB ports and third-party USB power adapters. Basically, if it’s a USB device, it’s always 5 volts.
However, although all USB devices run at the same voltage, some like the iPad require more power (wattage) than others. Since power is a factor of voltage and current (amperage), and the voltage in this case is a constant, then the charger must be able to supply more current to meet the increased demand for power. In the case of the iPad, the USB charger is able to provide 2.1A of current (or 10W of power); by comparison, standard computer USB ports normally provide only 0.5A (2.5W), and most USB chargers provide between 1A (5W) and 1.5A (7.5W). Some computer USB ports can provide up to 1.5A expressly for charging purposes, and modern Macs can even provide the 2.1A required for iPad charging on at least some of their USB ports.
Regardless of the current available, however, electronic devices only draw as much as they need. This means that if you connect an iPhone or iPod to an iPad charger, it will still only draw around 1A of current—the charger effectively runs at a lower power level, supplying 5W of charging power. Conversely, when you connect an iPad to an iPhone charger, it will try to get a full 2.1A, but won’t be able to as the charger is only capable of supplying 1A. This results in a considerably slower charging time as the iPad is effectively draining the battery as fast as it can be recharged.
The bottom line is that you can plug any USB device into any USB charging port without having to worry about damaging anything. It’s worth noting, however, that many cheaper USB charging accessories do not properly comply with the USB Battery Charging Specification and as a result many electronic devices—including the iPad, iPhone and iPod—will not detect these as valid chargers and will refuse to draw any power at all. This will still not harm anything, however—they simply won’t work.
- Will removing a credit card from Safari also remove it from Apple Pay?
- Can I mute Handoff calls coming into my Mac from my iPhone?
- How do I keep my iPhone calls from ringing on my Mac?
- Why doesn’t Traffic show up on my Today Notifications Screen?
- Why doesn’t my iPhone reconnect to Wi-Fi after I turn it on?
- Why can’t I see the iPad-style landscape view on my iPhone 6 Plus?
- Report: iPhone 8 likely to come in three glass-backed sizes
- Report: New Apple TV app to provide show recommendations
- Apple’s German website adds Apple Pay support page, but still no launch
- Notes from Apple’s Q4 2016 earnings call
- Apple Q4 2016: $46.9B revenue, 45.5M iPhones + 9.2M iPads sold
- Apple reportedly hiring engineers from BlackBerry, developing car operating system in Canada
- Apple releases PowerBeats3 Wireless earphones
- Apple Pay launch in Japan encounters major problems
- Apple releases iOS 10.1, tvOS 10.0.1, watchOS 3.1
- New details about Apple Watch Nike+ exclusives, availability
- Bowers & Wilkins P3 Series 2 Headphones
- Incase Icon, Pop, and Textured Snap for iPhone 7/7 Plus
- Philips Hue Motion Sensor
- Bowers & Wilkins P9 Signature Headphones
- Tech Armor FlexProtect and Shock Flex for iPhone 7/7 Plus
- SwitchEasy Flash and Fleur for iPhone 7/7 Plus
- Blue Microphones Raspberry Mobile Microphone
- Incipio Haven for iPhone 7 and Reprieve Sport for iPhone 7 Plus
- Mophie Hold Force Magnetic Case System for iPhone 7
- Speck Presidio and Tech21 Evo Tactical for iPhone 7
- Instant Expert: Secrets & Features of watchOS 3
- Instant Expert: Secrets & Features of tvOS 10
- Instant Expert: Secrets & Features of iOS 10
- Inside the betas: iOS 10 Photos gets Advanced Computer Vision
- Inside the betas: iOS 10 Music app delivers ‘clarity and simplicity’
- Inside the betas: iOS 10 Maps gets a major redesign
- Inside the betas: iOS 10 shakes up the user experience
- Inside the betas: watchOS 3 promises a real speed boost
- Inside the betas: A sneak peek at what’s new in tvOS 10
- Filling the Gap: A look at third-party HomeKit apps