Questions tagged [power]

The electricity drained by a device

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68
votes
10answers
152k views

Can I use 45/60/85W MacBook chargers interchangeably?

I have a 13" Macbook Pro that came with a 60W power adapter and a 15" Macbook Pro that came with a 85W power adapter. Can I use either adapter with either laptop? There seems to be disagreement in the ...
20
votes
7answers
29k views

iPad displays “Not Charging” when plugged into USB ports. What can I do?

When I plug my iPad into my computer's USB ports, the iPad battery area displays "Not Charging". I understand the iPad requires more wattage to charge compared to an iPhone or iPod, as evidenced by ...
29
votes
5answers
64k views

Is it OK to charge my iPhone with my iPad charger?

I have an iPhone 4 and an iPad. Since the iPad really charges best off the wall charger I keep it plugged in, but I usually just charge the iPhone off the computer. Although frequently if the iPad ...
53
votes
12answers
85k views

How can I avoid my MacBook Pro giving me minor shocks?

The aluminum Macbook Pro gives a mild shock when connected to a wall socket and charging. It only happens when I'm, for example, not wearing shoes or slippers and my feet are resting on the ground (i....
3
votes
3answers
835 views

Battery - Shut down or sleep an MBP

For the lifetime of a battery, is it better to shut down or sleep an Mac book Pro? Could anyone be able to explicit a full answer to this question?
1
vote
1answer
2k views

Danger of damaging 13" macbook pro by charging it with 85w charger? [duplicate]

We've got a range of laptops in our office all macbook pros some of which are 13" and some of which are 15". The 15" laptops came with 85w chargers, and the 13" came with 60w chargers. I want to ...
113
votes
6answers
140k views

How can I keep my Mac awake AND locked?

I want to leave my Mac awake overnight so it syncs 4GB of data from Dropbox. I need to prevent the machine from going to sleep because that pauses the Dropbox sync I've been using Caffeine to keep ...
40
votes
4answers
20k views

Use caffeinate to prevent sleep on lid close on battery

The native caffeinate utility is not working to prevent my macbook from sleeping when I close the display. Instead, the system sleeps and various network services ( VPN, screenshares, VOIP calls, ...
12
votes
2answers
7k views

Should I use the adapter or the battery?

I want to know when my MBP's battery was fully charged it's better to unplug my adapter and use my battery power or still let use adapter power? I somewhere read that when MBP's battery was fully ...
4
votes
2answers
4k views

Macbook Pro Battery 0% and wrong date

Model: MacBook Pro Retina, 13-inch, Early 2015 While I was working, I didn't realize that the battery was low and as a result, my MacBook Pro shut down when the battery had no power. So, then I ...
20
votes
4answers
23k views

How to monitor USB power consumption?

I'm looking for a way to monitor the power being drawn from the USB ports on my Mac. System Profiler doesn't appear to display this and I haven't been able to find any applications or tools to do the ...
7
votes
3answers
41k views

Does closing the lid put a MacBook Pro to sleep? Would it hurt the computer if I carry it around without shutting it down?

When I first got my MacBook Pro, it took less than 30 seconds to start up. Now, after several months, it takes about two minutes to startup and I can tell that it is not as responsive when using some ...
2
votes
3answers
28k views

Battery is not charging despite SMC reset

I have a problem with charging of my Battery which has been appeared last night. It was working perfectly well for a long time. All of my friends who had different laptops were so jealous at my ...
42
votes
6answers
19k views

Turning Power Chime Off

On new Macbook Pro, Power Chime runs. Whenever I delete from core services it comes right back. It makes a sound when plugging in your power cord even when the volume is at 0%. The solution I have ...
21
votes
12answers
36k views

How to retrieve current wattage info on OS X?

Is there a way to retrieve the current watt usage info on OS X Snow Leopard? I'm using mid-2010 iMac, so I'm not looking for just battery-related apps. Does OS X even monitor power usage? Do I need ...
14
votes
3answers
3k views

How does Apple calculate the energy consumption of a process in OS X Mavericks

In OS X Mavericks you can monitor the energy consumption of different processes in Activity Monitor. Here we can see 'Energy Impact' and Avg Energy Impact' and that the values can exceed 100. Also ...
16
votes
3answers
16k views

What are the consequences of using a low-wattage USB-C power supply with a MacBook Pro?

This question pertains to USB-C not MagSafe. MagSafe negotiates available power with the Dallas 1-wire protocol. USB Power Delivery (PD) is an unrelated protocol. Answers based on experience with ...
8
votes
1answer
21k views

How much power can be drawn from the lightning connector by a external device?

How much power can be drawn from the iPhone/iPad lightning connector by a external device? Update: The use case is a audio-related device for iPhone/iPads. It would require around ~100 mA at 3,3 ...
14
votes
3answers
18k views

Force “low power mode” on mac

When there is less than 5% battery left on a mac, the battery indicator goes red and system performance significantly drops - presumably in an attempt to make that remaining 5% last a little longer. ...
9
votes
2answers
17k views

How to reset a magsafe charger that doesn't charge macbook pro's battery?

I have a Magsafe charger (original) that doesn't charge my MacBook Pro's battery. When it is connected, it will allow the machine to switch to power adapter mode (meaning no battery consumption) but ...
9
votes
4answers
148k views

How do you get the Apple Watch out of Power Reserve mode?

I got it into power reserve but can't figure how to resume normal mode. I have tried tapping and pressing the screen and holding both side buttons.
5
votes
1answer
287 views

iPhone 7 Plus takes days to turn on showing Apple logo or black screen

I’ve had this issue for months but in the last couple of days it’s got very very bad. When my phone runs out of battery it needs like 2–3 days to turn back on. At the beginning of this problem the ...
4
votes
2answers
2k views

Transporting from home to work (~10 min by car), should I just make my MacBook Pro sleep, or shut it completely down first?

I just got a new MacBook Pro, and is looking at how the power modes work, and according to this article: About Energy Saver sleep and idle modes in Mac OS X, making it sleep by closing the lid (say) ...
4
votes
6answers
10k views

My MagSafe to MagSafe 2 converter becomes extremely hot. Why?

Out of nothing, my MagSafe to MagSafe2 converter became extremely hot while charging. So hot, I could not even touch it. What could cause it? I've been using it so I can leave multiple old 85W ...
3
votes
1answer
7k views

Are there no explicit Power modes in Mac?

Does Macbook Pro not provide power modes (Power Saver, High Performance, etc) like a Windows laptop? If there is nothing like that, then I'd assume that OS X manages optimal settings itself. Or is ...
3
votes
1answer
12k views

Can a thunderbolt cable transmit power?

Is it possible for thunderbolt to transmit power to or from a Macbook Pro. Perhaps to power/charge it or power/charge an external device?
2
votes
1answer
164 views

How to know which one is used when charging a MacBook Pro with usb-c from multiple power adapters?

There is this great question: What happens if you plug more than one charger in the new MacBook Pro (2016)? It doesn't tell me how to find out from which source the MacBook is charging though. ...
1
vote
2answers
93 views

MacBook Pro never goes to sleep

I got a brand new mid-2015 MacBook Pro 15", OSX 10.11.3. Display never turns off even it is configured to turn off after 10 mins in power adapter AND in battery mode. Screen saver (aerial) stays ...
1
vote
1answer
440 views

Show USB power use

I wanted to see how much power the Anker Astro external battery draws when charging from the MacBook Pro (Retina, 15-inch, Late 2013) (right hand port next to the SD slot), but when listing the USB ...
1
vote
4answers
3k views

MacBook Pro turned off and won't turn on!

I was just using my laptop normally when suddenly the whole computer just shut down. I turned it back on straight away and it was fine. Another hour passed and it did the same thing. I could also turn ...
40
votes
10answers
132k views

What would happen if I use a power supply with a different wattage than the system is designed for?

My girlfriend has a Macbook Air. The power supply is smaller and lighter than the Pro. It has an output of 14.85V and 3.05Amps. My Pro Retina has a power supply that is 20V and 4.25 Amps. Both ...
23
votes
4answers
23k views

Why does GPS on the iPhone use so much power?

I keep reading in articles that GPS on the iPhone, or any cell phone for that matter, uses a lot of power, but I've never heard an explanation of why. Why is this? The phone doesn't have to transmit ...
13
votes
3answers
4k views

Can I restore pre-Mavericks power key behavior?

Mavericks changed the behavior of my MacBook Air's power key to put the Air to sleep immediately when pressed briefly. Prior to Mavericks, the power key would summon the Shut Down dialog. As ...
10
votes
4answers
16k views

What is the iPhone's standby policy regarding WiFi and 3G?

I have an iPhone 4s with the latest iOS. It seems that when I wake it up from standby, it switches from 3G (or EDGE) to WiFi. Judging from that, I suspect it turns off WiFi when in standby, and only ...
9
votes
4answers
8k views

Does an iPad consume more battery power when there are multiple applications open?

Does an iPad consume more battery power when there are multiple applications open compared to let's say, having only one application resident in memory? If there are differences between the ...
8
votes
1answer
3k views

How does the iPhone know it's not using an Apple cable?

Sometimes when I plug a cable in to charge, the iPhone says it may not work with this device. How does it know it's not an Apple cable?
6
votes
2answers
17k views

Monitoring power consumption on Mac

The Android OS monitors the power consumption of running apps and hardware (display). As you may guess, this is a useful feature as it allows to track down energy greedy apps. Is there an application ...
4
votes
3answers
14k views

MacBook Pro 2011 logging itself out after a period of inactivity

when I am not using it, at some point, every day, my MBP tries to log out on its own. When I 'wake it up' I can see message windows about "applications aborting logout", obviously because some ...
2
votes
2answers
5k views

Can a low-wattage adapter fully recharge the battery of a turned off MacBook?

MacBooks come with power adapters that provide a certain wattage (for example 87 W) required to keep the computer running and charge the battery. If used with a lower-wattage power adapter (for ...
10
votes
2answers
960 views

Why can my Mac charge my iPad but other computers can't?

What do Macs do differently so its USB ports can charge my iPad, but if I plug into a USB port on my PC I get the "not charging" message?
9
votes
2answers
38k views

How do you check how much current a Mac USB port can deliver?

This question is similar to the superuser question "How to check how much power a USB port can deliver", which is answered for Linux and Windows. How do you check the same on a Mac?
9
votes
4answers
40k views

Can I (or should I) use a MacBook charger on my iPhone?

I recently got a MacBook with the USB-C charger. It comes with a 29-watt power brick, and I was wondering if I should use this to charge my iPhone. I've heard that the iPad power brick (I think 10 ...
4
votes
6answers
15k views

Is my MagSafe covered under my MacBook's AppleCare?

I have a white 2010 MacBook, and the outer casing for the wire on the MagSafe power adapter has developed a small split. Is this something that may be covered under my MacBook's AppleCare? Is it ...
3
votes
2answers
18k views

Out of warranty MBP ,Burned Magsafe port and frayed charger cable - repair option and cost?

I have a MBP 15" 2011 model and has is the burned magsafe port (leftmost pin melted) which i noticed today. The connector gets too hot sometimes ( but remains ok when I charge in sleep mode). ...
2
votes
1answer
106 views

Can I use a DC 60W 18v 3A solar pannel to power my macbook pro 15" retina mid-2012?

I have found this solar pannel ( https://fr.aliexpress.com/item/Suaoki-60-w-Panneau-Solaire-5-v-USB-et-18-v-DC-Sortie-Portable-Pliable-Puissance/32935273533.html?spm=a2g0w.search0104.8.83....
1
vote
1answer
373 views

USB to MagSafe 2 Adapter

In case of an emergency, I'd like to use my solar powerbank to charge my Macbook 2015 13". It outputs 2.1A 5V, and I learned that the MBP can be charged with that, but I don't know if that's actually ...
0
votes
2answers
7k views

Is it better for the battery to leave the iPad plugged when charging is done?

I charge my iPad. Later, I notice that the battery is charged at 100 %. Now, what is better to preserve the battery capacity ? Unplugging the cable. Leaving the cable plugged. The answer may vary ...
5
votes
1answer
879 views

Macbook Pro Power Consumption

I was wondering if it is possible first of all to get the overall power consumption for my MacBook? And if it is possible can I get this power consumption for each peripheral running (like ...
4
votes
3answers
3k views

“usb device was drawing too much power” error message

Ever since I upgraded to Lion, I've been getting this error message a lot. It seems to trigger(not every time though) when I plug in my iPhone to the usb port on my keyboard. The only other USB ...
4
votes
1answer
136 views

Change what percentage/time remaining causes the battery icon on Mac to go red

I'm dead broke. So, I have a cheap battery for my dead-broke-esque 2008 MacBook. It only lasts about 2 hours on a full charge. However, it's a little goofy at times. Not in a dangerous way, just that ...