Mac ac power adapter

Mac ac power adapter DEFAULT

Mac AC Power Adapter Plug Duck Head US Wall Charger AC Cord US Standard Duck Head Compatible with Mac Book/Mac iBook/iPhone/iPad/iPod AC Power Adapter Brick

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Great Replacement for Your Cracked Adapter

The Plug Compatible with All US Plug Mac Products, iPhone, iPod or iBook Power Adapters.

It is small and light,it can be used to replace the old crack adapter and let your power adapter work properly.

It is good for you when you are at home or go out for traveling!


The AC plug only work with US and Canada plug adapters or chargers, please do not use it on European chargers.

Package Included:

2 x US AC Wall Plug Duck Head Adapter


How to Connect the AC Adapter for a MacBook Pro

By Jeff Grundy

MagSafe adapters charge MacBooks in three to five hours.

According to test results compiled by, the battery in an Apple MacBook Pro laptop lasts five to six hours even with the Wi-Fi adapter turned on and the processor running full speed. This means entrepreneurs can be more productive for longer when on the road. Nevertheless, you still have to connect the AC power adapter to charge the MacBook Pro occasionally. Like AC adapters for other laptops, the MagSafe adapter used with the MacBook Pro allows you to use the notebook while charging the battery; it connects to any standard V or V electrical outlet. The MagSafe adapter’s innovative design helps to prevent accidental drops and stress on the charging socket but also makes connecting the adapter a bit different from ones designed for other laptops.

Align the five pins on the smaller end of the MagSafe AC power adapter with the pinholes in the adapter connector on the side of the MacBook Pro. Hold the end of the adapter so that it almost touches the pins in the connector on the laptop but do not push the adapter into the socket.

Release the end of the MagSafe AC power adapter cable and allow it to snap into place inside the socket. The MagSafe adapter has a magnetic edge that connects and secures it to the pins inside the charging socket. The magnetic edge of the adapter ensures a reliable and secure connection between the adapter and the charging socket while allowing the cable end to disconnect easily in the event someone trips over the power cord. If someone trips over the power cord while the laptop is charging, the adapter end simply pulls away from the MacBook Pro rather than pulling the notebook off the desk onto the floor.

Plug the power cord that connects to the power converter brick at the opposite end of the AC adapter cable into an electrical socket or power strip. Alternatively, unplug the standard power cord from the power converter brick and connect the longer extension cable included with the MacBook Pro. After you connect the extension power cord to the power converter brick, plug the other end of the cord into an electrical socket.

Pull the two white prongs located on the rear of the power converter brick out until fully extended. Wrap any excess slack in the power cord around the two white prongs.



  • Disconnect the MacBook Pro's MagSafe adapter by gripping the connector end of the adapter cable and wobbling it up and down or side to side. Never pull the end of the MagSafe adapter straight out, as this can damage the magnetic seal on the edge of the adapter.

Writer Bio

Jeff Grundy has been writing computer-related articles and tutorials since Since that time, Grundy has written many guides to using various applications that are published on numerous how-to and tutorial sites. Born and raised in South Georgia, Grundy holds a Master of Science degree in mathematics from the Georgia Institute of Technology.

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The real story behind MagSafe, USB-C PD, and why you need a 20W AC charger

If you want to charge your iPhone 12 using MagSafe, Apple recommends using certain 20W AC adapters — and they don't need to come from Apple, despite what you may have heard. We explain what the requirements are, and why an older 18W adapter just won't cut it.

Apple released the iPhone 12 lineup with an all-new accessory and charging system called MagSafe. The name was previously used to refer to a magnetic quick-release cable for Apple's portable Mac line, but had since been lost when Apple shifted to USB-C.

What is MagSafe?

MagSafe in this case, refers to the magnetic capability of the accessories more so than the safety the accessories provide like it did prior. One accessory released is the MagSafe Charger, which is a large charging puck that attaches to the rear of the iPhone 12 for wireless charging. Unlike other wireless chargers, it magnetically grips the iPhone when in use which means you can pick up and use the iPhone while charging.

The large surface area coupled with Apple's own proprietary design allows for up to 15W of delivered power to a device when charging when using the MagSafe charger vs only W on Qi chargers. The ability to charge at twice the speed of Qi is a major benefit to using MagSafe, but it does come with some caveats.

Buckle up. This is going to get a little more technical than we normally get. If this stops you from reading further, here's the takeaway: if you don't want to buy Apple's USB-C AC adapter, any USB-PD one with equivalent specs will do to get that faster charging speed, and a lesser one, won't.

USB-C Power Delivery

USB PD is a specification for handling higher power on USB and allows a range of devices to charge quickly over a USB connection. It facilitates negotiation between two devices so they can determine how much power can be pulled from the charger. Power Delivery offers multiple power profiles from 5V to 20V, including a crucial amp power profile. More on this in a bit.

The USB PD spec was released in mid and the rollout of the technology takes time. Adapters purchased before may not have the spec, and thus, will not and cannot meet the charging requirements for MagSafe. Apple chose this spec for a reason, it is a more intelligent standard that understands more about the device it is charging.

A USB PD device would negotiate power based on power requirements alone. The USB PD spec allows the adapter to gain more information from the device while charging, like temperature and charging malfunction.

The USB PD spec also includes more intelligence for controlling amperage and voltage while charging. When adjusting voltage or amperage it can move by as little as 20mV or 50mA steps, which is constantly negotiated every 10 seconds by the source.

So while Apple could have gone with an older spec for its 15W charging requirements, it decided to engineer a safer and more efficient solution by relying on the newer spec. USB PD is backwards compatible though, which is why you will still get 10W out of older chargers, even if its rated for 96W.

If the MagSafe puck and the AC adapter can't negotiate the 9V and amps, USB Power Delivery will default to the highest common mutually compatible voltage and amperage that it can, not to exceed that 9V or amps. This will vary, depending on what AC adapter you have, given that the MagSafe puck can handle that 9V and amps.

USB power profiles

Monotonic Incremental Power Rule (Image Credit:Texas Instruments)

Monotonic Incremental Power Rule (Image Credit:Texas Instruments)

The PD spec includes specific requirements for available voltage rails for a given power rating. Any adapter above W will include only 5V delivered. Greater than 15W will utilize both 5V and 9V.

For even more power and variability greater than 27W adapters will have 5V, 9V, and 15V rails, and finally any adapter greater than 45W will have 5V, 9V, 15V, and 20V power options.

Other voltages can be offered for negotiation, but cannot exceed the highest required voltage "rail" in the adapter. Once a device is connected, it negotiates with the adapter for the best combination of voltage rails to achieve maximum efficiency while charging.

Adapters can offer any amperage up to a 5A rating and will determine the best amperage to use when negotiating. Modern devices choose a variable voltage and constant amperage for better temperature control. Only the 20V rail uses the 5A rating to achieve the W power rating for something like a MacBook Pro, while the rest rely on A to 3A ratings for constant current.

Like we said, Apple uses 9V and A for its MagSafe Charger to get to 20W. You can only get this combination in USB PD 20W or higher wattage adapters — and Apple is not alone in providing that combination. A higher wattage alone won't work.

That 15W wireless charging in the MagSafe adapter

Apple recommends using a 20W adapter, but doesn't specify what spec is needed. Conveniently, the one with the correct spec is one they recently started selling and include with the inch iPad and iPad Air 4. There are 18W USB-C adapters available, but as we've discussed, they do not meet the minimum requirements for charging at 15W.

Apple says the MagSafe Charger will charge with any adapter greater than 12W, but at a reduced rate. Tests show around 10W or less when used with adapters below 20W. When the MagSafe Charger negotiates for power it specifically looks for the 9V x A supply, which is only present in 20W PD adapters — and only some with a greater power potential, given that it specifically needs that 9V x A supply. This is why it defaults to the 5V x 2A supply when using the 18W adapter, and will do the same with most — but not all — existing 60W USB-C power adapters.

Why can't a 15W adapter get 15W out of the MagSafe charger?

Apple's 20W adapter next to Anker's 20W adapter

Apple's 20W adapter next to Anker's 20W adapter

Even accounting for USB PD requirements mentioned above, no system will ever be % efficient. Even if we ignored the industry specifications and built a 15W adapter for the 15W wireless charger, it wouldn't meet the minimum requirements to charge at full speed.

No system is inherently perfect, and every system will lose efficiency in charging based on multiple factors:

  • Length of cable used
  • Size of cable used
  • Conductor used (Copper)
  • Surface area of connected charger
  • Heat generation

These characteristics affect regular charging over a cable plugged directly to a device, so a 15W adapter connected to a suitable cable will still only charge less than 15W due to efficiency losses. In fact, the heat given off by your iPhone when charging, wired or wireless, is generated by the chemical reaction of charging the battery, which represents a loss in charging efficiency.

There is already some loss in efficiency in charging with a direct cable, just because of the resistance of the cable itself. A short and thick cable will have less resistance than a long and thin cable. The more resistance a cable has, the more energy is converted to heat. This is referred to as copper loss, and is inherent to any electrical system just as friction is inherent to a mechanical system.

When passing current through a charging coil, multiple losses are happening. First is copper loss, due to the thickness of the coil you are introducing more resistance, thus more heat. The second loss is from producing a magnetic field within the charging coil called eddy current loss, which also introduces heat to the system.

The heat generated from wireless charging due to how energy is passed between charging coils represents the sheer inefficiency of wireless charging. While more convenient, assuming a constant rate of battery charge, you are using more power per minute when using MagSafe or Qi. Alternatively, using the same charger with the same power per minute, you will deliver less power to the battery wirelessly charging than when using a cable.

What MagSafe, Qi, and USB-C PD practically means for buyers

If you purchase a MagSafe Charger, be aware of the power adapter you use with it. Purchasing the Apple 20W adapter with the demanded specs for the full 15W charging from quality manufacturers will get you the desired results. Be sure to follow Apple's recommendations though, as 20W with USB PD is the minimum in order to charge with MagSafe at full efficiency.

Some speculate that Apple has introduced an artificial limitation to force users to buy new power adapters. Other than the minimum spec that has been a factor in tech purchases since the dawn of personal computing, there is no secret sauce.

Between inefficiency and energy loss when wireless charging, voltage profile requirements, and intelligent charging systems, Apple's minimum requirement fits within industry standards. But, Apple's isn't the only charger that will, and we'll be discussing which will work, and which won't, soon.

MacBook Pro 16 How to Properly Plug-In and Charge

Find the right power adapter and cable for your Mac notebook

Learn which power adapter, cable, and plug works with your Mac notebook computer.

Power adapters for Mac notebooks are available in 29W, 30W, 45W, 60W, 61W, 85W, 87W, and 96W varieties. You should use the appropriate wattage power adapter for your Mac notebook. You can use a compatible higher wattage power adapter without issue, but it won't make your computer charge faster or operate differently. If you use a power adapter that is lower in wattage than the adapter that came with your Mac, it won't provide enough power to your computer.

Mac notebooks that charge via USB-C come with an Apple USB-C Power Adapter with detachable AC plug (or "duckhead"), and a USB-C Charge Cable. 

Mac notebooks that charge via MagSafe come with an AC adapter with MagSafe connector and detachable AC plug, and an AC cable.

The images below show the style of adapter that comes with each MacBook, MacBook Pro, and MacBook Air. If you're not sure which model Mac you have, use these articles:


Apple 29W or 30W USB-C Power Adapter and USB-C Charge Cable

  • MacBook models introduced in or later

Apple 30W USB-C Power Adapter and USB-C Charge Cable

  • MacBook Air models introduced in or later


Apple 61W USB-C Power Adapter and USB-C Charge Cable

  • inch MacBook Pro models introduced in or later


Apple 87W USB-C Power Adapter and USB-C Charge Cable

  • inch MacBook Pro models introduced in or later


Apple 96W USB-C Power Adapter and USB-C Charge Cable

  • inch MacBook Pro models introduced in

Make sure you're using the correct USB-C charge cable

For the best charging experience, you should use the USB-C charge cable that comes with your Mac notebook. If you use a higher wattage USB-C cable, your Mac will still charge normally. USB-C cables rated for 29W or 30W will work with any USB-C power adapter, but won't provide enough power when connected to a power adapter that is more than 61W, such as the 96W USB-C Power Adapter.

You can verify that you're using the correct version of the Apple USB-C Charge Cable with your Mac notebook and its USB-C AC Adapter. The cable's serial number is printed on its external housing, next to the words "Designed by Apple in California. Assembled in China." 

  • If the first three characters of the serial number are C4M or FL4, the cable is for use with an Apple USB-C Power Adapter up to 61W.
  • If the first three characters of the serial number are DLC, CTC, FTL, or G0J, the cable is for use with an Apple USB-C Power Adapter up to W.
  • If the cable says "Designed by Apple in California. Assembled in China" but has no serial number, you might be eligible for a replacement USB-C charge cable.

MagSafe 2

85W MagSafe power adapter with MagSafe 2 style connector

  • inch MacBook Pro models introduced in through

60W MagSafe power adapter with MagSafe 2 style connector

  • inch MacBook Pro models introduced in through

45W MagSafe power adapter with MagSafe 2 style connector

  • MacBook Air models introduced in through

About the MagSafe to MagSafe 2 Converter

If you have an older MagSafe adapter, you can use it with newer Mac computers that have MagSafe 2 ports using a MagSafe to MagSafe 2 Converter (shown).

MagSafe "L" and "T" shaped adapters 

60W MagSafe power adapter with "T" style connector

  • inch MacBook Pro models introduced in
  • MacBook models introduced in through mid

60W MagSafe power adapter with "L" style connector

  • inch MacBook Pro models introduced in through
  • MacBook models introduced in late through

85W MagSafe power adapter with "T" style connector

  • inch MacBook Pro models introduced in through
  • inch MacBook Pro models introduced in through

85W MagSafe power adapter with "L" style connector

  • inch MacBook Pro models introduced in through
  • inch MacBook Pro models introduced in through

45W MagSafe power adapter with "L" style connector

  • inch MacBook Air models introduced in through *
  • inch MacBook Air models introduced in through

* Adapters that shipped with the MacBook Air (Original), MacBook Air (Late ), and MacBook Air (Mid ) are not recommended for use with MacBook Air (Late ) models. When possible, use your computer's original adapter or a newer adapter.

Published Date: 


Power mac adapter ac

You plug in your adapter to your laptop, and the battery doesn’t charge reliably. Sometimes, your Mac dings to let you know it’s plugged in to power; other times, you have to plug and unplug, or even restart your computer. What’s up?

Battery charging involves three separate elements, so you have to go through a process of troubleshooting to identify which one is faulty.

The battery

For several releases of macOS, Apple has provided alerts and information about the health and status of a laptop’s battery. macOS warns you if something’s actively wrong with a battery when it determines this.

In macOS Catalina and earlier, you can Option-click the battery icon in the menu bar, and get a little more insight about the state of the battery. In macOS Big Sur, there’s a lot more detail about the battery available by default, but the condition is nested more deeply: go to the Battery preference pane, click Battery, and click Battery Health.

mac big sur battery dropdownIDG

The condition should be listed as Normal, but if the battery’s maximum capacity has dropped below a certain point (which Apple doesn’t specify), it might say Service Battery. You may also see one of a number of other messages that Apple doesn’t document, such as Service Recommended, Replace Soon, or Replace Now, all of which have a little more urgency, as the operating system has deemed the battery holds a charge poorly, or even not at all. If the battery dies entirely, an X appears through the battery icon, and the message reads No Battery Available.

In Big Sur through many earlier releases,  you can hold down the Option key and select &#; > System Information and click the Power item under Hardware in the left-hand navigation bar. Look for Condition there, where you can also see Cycle Count and, on certain models and versions of macOS, Maximum Capacity. The Cycle Count isn’t the number of times you’ve charged, but rather the total capacity of the battery divided by the total energy every used. The more cycles, the lower total capacity the battery has remaining, though it should be both years and hundreds of cycles before you see degradation below 80 percent. (A cycle measures percent of the capacity discharged, not the time between being unplugged and plugged back in. If you deplete to 50 percent on two successive days and recharge to percent, it counts as one cycle.)

In Big Sur, you can also use the Battery preference pane’s Usage History view to examine how and when your battery has been in use and when it’s been recharged. Starting in Big Sur, Apple automatically throttles and adjusts your charging pattern to reduce stressing the battery: it no longer charges the battery to percent at all times, but based on your usage, keeps it at 80 percent whenever possible. Lithium-ion batteries face additional wear when fully charged all the time, which reduces battery life. This chart may reveal a pattern of slow failure.

mac big sur battery historyIDG

The adapter

It’s natural to look at your power adapter for signs of wear, like a crushed portion, fraying cable insulation, bent or marked AC plug blades, dirty or bent parts of the laptop connector, or other signs of problems. However, a frequently used adapter may look fine to the eye, but the internal wiring or circuitry and components in the power conversion part that handles AC-to-DC transformation could be on their way out.

If, when you plug in your adapter, your computer doesn’t seem to charge immediately or reliably, see if you can borrow an identical or similar adapter from someone else temporarily to see if it helps. You might even purchase a replacement from a store with a liberal return policy, and keep it if that’s the problem. (For Macs that use MagSafe, please, for your own safety, avoid third-party MagSafe chargers and adapters. Read the reviews to understand the risk you’re taking.)

With MagSafe connectors, find the appropriate matching adapter; Apple has all the information in this note.

For Macs with USB-C ports (released starting in ), it’s okay to test with an adapter that’s rated with higher or lower wattage than your laptop, by the way. If you have a laptop that comes with a watt adapter, you can use an 89W one or vice versa: the laptop that requires 29W charges fully when in use with a paired 29W adapter, but it doesn’t pull in more electricity than necessary with a higher-wattage one. Likewise, an 89W laptop can charge with a 29W one, though it may charge very, very slowly or you might even see the battery decline. But you can still check whether the adapter is recognized and the adapter is attempting to charge it.

All of Apple’s USB-C power adapters have a removable charging cable. Try swapping the cable out. You need another one that’s designed to carry the wattage noted. Many USB-C cables are designed with a maximum wattage that’s far below the capacity of the adapter, or can only carry data and low-wattage power over USB, such as is used to charge an iPhone or iPad.

Apple notes also in its notes on troubleshooting USB-C adapters: “Some possible sources of line noise include lights with ballasts, refrigerators, or mini-refrigerators that are on the same electrical circuit as the outlet you’re using. Plugging the power adapter into an uninterruptible power supply (UPS) or an outlet that’s on a different circuit can help.” I have never seen this kind of behavior, nor heard of it from readers, but Apple clearly has.

Charging circuitry in the laptop

If you’ve gone through the above troubleshooting and still have problems, particularly intermittent, the internal components required for charging may be configured incorrectly, failing, or have suffered damage. This can explain why restarting your computer allows it to start charging again, or it might only charge when it’s been shut down, and the components have cooled.

If there’s a setting fault, you can reset the System Management Controller on your Mac, which handles battery charging, fans, sensors, lights, and a number of other active hardware components. Follow Apple’s instructions for your Mac model to reset the SMC, and see if that solves the problem.

If not, your final step is to find service, hopefully under AppleCare. If your AppleCare has expired, I recommend finding a shop (via recommendations from friends and colleagues) that can repair components or source used parts. Because of the integrated nature of power in most of Apple’s laptops, it can be an expensive repair to get a new motherboard or subsystem board, when a used one may work just as well.

This Mac article is in response to a question submitted by Macworld reader Michael.

Ask Mac

We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to [email protected] screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.

Apple power adapter extension cable


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