iPhone Charging (USB Computer vs. Wall)

l3oom

macrumors newbie
Original poster
Sep 26, 2016
16
0
Hi,

I typically charge my phone at work using a USB Lightning cable plugged directly into the front of my desktop computer. I usually don't charge it much elsewhere, as it holds enough juice until the next day, although on the weekends will sometimes use the wall charger.

Is there anything wrong with using USB/desktop connection as your primary charge source?

I just got the iPhone SE and haven't charged it by a wall charger yet, only USB. Is there anything to worry about when charging this way?

I see mixed insight here:
https://www.quora.com/Should-I-charge-my-phone-by-computer-using-a-USB-or-directly-to-the-wall

Let me know your thoughts. I've also read somewhere that the FIRST charge should be via a wall charger, why...I have no idea. Let me know if anyone knows.
 

elf69

macrumors 68020
Jun 2, 2016
2,316
482
Cornwall UK
USB on computer will charge slower at only 500mAh wall charger is 1000mAh or 2000mAh depending on phone/charger you have.

Some say the slower usb charge is better for long term battery use.

I only use wall charger for my iphone and all my previous android phones.
Never had a problem in past with this.

I do not think what you are doing is going to hurt anything.
Just carry on.
 

C DM

macrumors Sandy Bridge
Oct 17, 2011
47,557
16,059
Nothing wrong and nothing to worry about either way as long as the device is getting charged.
 
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BigMcGuire

Contributor
Jan 10, 2012
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Tons of battery misinformation out there. With the iPhone's Lithium Ion battery you don't need to first charge anything or do anything special out of the box. Just use it. Doesn't really matter where you charge it either - just realize that computers (especially USB 2.0 ports) can charge VERY very slowly versus the included phone charger (1amp). A lot of us even use chargers that are 2.4 amps and above (iPad charger or 3rd party) to charge our phones even faster. The phone will only ask for current that is safe.

The phone trickle charges from 90% - 100% and that can take hours - it will do this even if the phone displays 100%. You can never OVER charge a phone - it will turn off charging when it reaches true 100% so leaving it plugged in is fine (though if you leave it plugged in for weeks on end, take it off the charger and let it drop to 40% every few weeks).

Want to take care of your phone's battery? Don't let it get hot - don't leave it in the sun or in a hot car. Try to minimize the times you go below 20% capacity. Leaving it plugged in for hours at a time or charging it whenever you can is actually a good thing and will not harm your battery.

http://www.apple.com/batteries/maximizing-performance/
http://www.apple.com/batteries/why-lithium-ion/

And if you want some heavy reading:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
 

Mlrollin91

macrumors G5
Nov 20, 2008
13,482
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Ventura County
Whats the charging difference between a computer with USB 2.0 and 3.0? I've noticed, using Coconut battery that my phone charges at a higher watt with USB 3.0. I don't know if its just coincidence, but I've seen my iPhone 7Plus reach 7.9watts in the USB 3.0 slot, but 5.5watts in the 2.0 slot.
 

BigMcGuire

Contributor
Jan 10, 2012
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California
Whats the charging difference between a computer with USB 2.0 and 3.0? I've noticed, using Coconut battery that my phone charges at a higher watt with USB 3.0. I don't know if its just coincidence, but I've seen my iPhone 7Plus reach 7.9watts in the USB 3.0 slot, but 5.5watts in the 2.0 slot.
USB 2.0 is 500 mAh and USB 3.0 is 900 mAh. Some manufacturers do more for USB 3.0.

https://support.apple.com/en-us/HT204377
 
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bufffilm

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May 3, 2011
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I have USB ports as well as a 6 port charger which can go to up to 2.1A per port.

I prefer the USB port...slower charge which some say is better for the battery. For iPads needing more than 1A juice, like my sisters Mini1 or my Tab Pro 8.4, they go on the 6 port charger.
 

BigMcGuire

Contributor
Jan 10, 2012
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California
Whats the logic to slower charging is better? Is it because it reduces the heat?
Yes, reduction of heat. The faster you charge a battery the higher the heat is. Rapid charging on my Nexus 6 (when I had it) resulted in a very hot phone - but supposedly the rapid charging took that into account and varied the current so it wouldn't overheat. But heat is #1 killer of a lithium ion battery.

But will a normal user see a difference charging off of a 900 mAh USB 3.0 port or a 2.4a iPad charger ? Probably not in a 2 year 300+ cycle lifetime. I've charged my 6+ off of an Anker 4.8a charger for its 1.5 years and after 250? cycles it still had 99.7% life left (coconutBattery).
 
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Mlrollin91

macrumors G5
Nov 20, 2008
13,482
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Yes, reduction of heat. The faster you charge a battery the higher the heat is. Rapid charging on my Nexus 6 (when I had it) resulted in a very hot phone - but supposedly the rapid charging took that into account and varied the current so it wouldn't overheat. But heat is #1 killer of a lithium ion battery.

But will a normal user see a difference charging off of a 900 mAh USB 3.0 port or a 2.4a iPad charger ? Probably not in a 2 year 300+ cycle lifetime. I've charged my 6+ off of an Anker 4.8a charger for its 1.5 years and after 250? cycles it still had 99.7% life left (coconutBattery).
Awesome. I always try not to charge my phone after heavy gaming as the device is already hot. I use Coconut battery whenever I can to verify the temperature of the battery. I do use a 10watt iPad charger as my primary charging unit, but have never noticed any extreme heat from it. Usually never even breaks 90 degrees.
 
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BigMcGuire

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Awesome. I always try not to charge my phone after heavy gaming as the device is already hot. I use Coconut battery whenever I can to verify the temperature of the battery. I do use a 10watt iPad charger as my primary charging unit, but have never noticed any extreme heat from it. Usually never even breaks 90 degrees.
Yeah, that's definitely going to help your battery long term. I love coconutBattery. Was so sad that I couldn't run it anymore on the phone because of iOS 10 :) But I'll settle for using it on my Mac.

The phone will only ask for what it wants from the wall, so you could have a 10a charger and it would still only draw 2.1-2.2? amps (I believe). So you're safe. iPad chargers are very nice and provide very clean power - love those things (especially the 12watt one - but some cool macrumors member did a test between the 10watt and 12watt ipad chargers and there was hardly any difference in overall charge time).
 
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bufffilm

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Whats the logic to slower charging is better? Is it because it reduces the heat?
Some articles I read...favor a slower charge to put less 'stress' on the battery. Heat and other factors.

It's funny because my ipad2 can take a faster charger (> 1A). I have a Cydia app that measures the charging current.

Prior to getting the 6 port charger a month ago, my iPad 2 was always charged via the USB port or the 1A wall charger - 5 years of wear and only a 18% degradation in the battery in all that time.

For that reason, I will continue to 1A charge it. The 2A tablets go on the fast charger as will the Pro (once I get one).

My 6s also is charged by the USB port...not putting it on the faster charger.
 
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BigMcGuire

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Some articles I read...favor a slower charge to put less 'stress' on the battery. Heat and other factors.

Prior to getting the 6 port charger a month ago, my iPad 2 was always charged via the USB port or the 1A wall charger - 5 years of wear and only a 18% degradation in the battery in all that time.
Yeah, you're right. I believe Battery University is a huge proponent of charging slower. Interesting results - I'd believe after 5 years you'd see advantages of 1a vs 2a, especially if shallow depth of charge/discharge (40-80%).
 

bufffilm

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Yeah, you're right. I believe Battery University is a huge proponent of charging slower. Interesting results - I'd believe after 5 years you'd see advantages of 1a vs 2a, especially if shallow depth of charge/discharge (40-80%).
Prior to 2015, I would plug in the ipad2 at around 25-30% left. Since then, I'm doing it at around 45-55% instead.

At the same time (2015) i also stopped the calibration thing where I would drain it down to 0% every 2-3 months.

Accuracy hasn't really suffered since then either.
 
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Thor_1

macrumors 6502a
Sep 18, 2016
950
599
Texas
Hi,

I typically charge my phone at work using a USB Lightning cable plugged directly into the front of my desktop computer. I usually don't charge it much elsewhere, as it holds enough juice until the next day, although on the weekends will sometimes use the wall charger.

Is there anything wrong with using USB/desktop connection as your primary charge source?

I just got the iPhone SE and haven't charged it by a wall charger yet, only USB. Is there anything to worry about when charging this way?

I see mixed insight here:
https://www.quora.com/Should-I-charge-my-phone-by-computer-using-a-USB-or-directly-to-the-wall

Let me know your thoughts. I've also read somewhere that the FIRST charge should be via a wall charger, why...I have no idea. Let me know if anyone knows.
This is from personal experience. Avoid cheap after market chargers and cords. My daughters phone was doing crazy things and I discovered she was using a cute (cheap) charger. Once she switched to the one that came with the phone, all was normal.
 
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BigMcGuire

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Jan 10, 2012
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This is from personal experience. Avoid cheap after market chargers and cords. My daughters phone was doing crazy things and I discovered she was using a cute (cheap) charger. Once she switched to the one that came with the phone, all was normal.
Yes, I bought a large batch of super cheap 6ft iphone cables and several didn't work, and the ones that did refused to charge anywhere near 1a (took 8 hours to charge my 6s+). Some make the touch screen not work. Stick with the MFI certified (I like the Anker brand).
 

Brookzy

macrumors 601
May 30, 2010
4,747
4,723
UK
Remember that charging from a USB port on a computer does not necessarily mean you are charging at a slow rate. Modern Macs support up to 2.1A via USB.
USB 2.0 is 500 mAh and USB 3.0 is 900 mAh. Some manufacturers do more for USB 3.0.

https://support.apple.com/en-us/HT204377
This article puzzles me because it states the maximum a Mac can output over USB is 900mA (if I'm reading it correctly), yet if I plug an iPhone or iPad into my 2015 iMac I get the following in System Profiler:

Current Available (mA): 1000
Current Required (mA): 500
Extra Operating Current (mA): 1600
Sleep current (mA): 2100​
 
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bufffilm

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Yes, I bought a large batch of super cheap 6ft iphone cables and several didn't work, and the ones that did refused to charge anywhere near 1a (took 8 hours to charge my 6s+). Some make the touch screen not work. Stick with the MFI certified (I like the Anker brand).
My ipad2 uses generic cables (bought years ago), the phone has the Apple one.

But I bought 2 Anker cables for when people come over and as a backup...pretty inexpensive and of course, the quality is tops. I know there are more expensive cables out there...I'm not convinced they are worth it though, but I'm not particularly hard on mine's.
 
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Mrbobb

macrumors 601
Aug 27, 2012
4,987
192
I was curious as to what new things people are saying I clicked the link..... and read the expert chemists.

Suggestion: Don't go the deep end, stop reading how you should charge, keep doing whatever is convenient. Spend $$money to make your life easier and not further add stress and obsessions.
 

BigMcGuire

Contributor
Jan 10, 2012
4,623
5,670
California
Remember that charging from a USB port on a computer does not necessarily mean you are charging at a slow rate. Modern Macs support up to 2.1A via USB.


This article puzzles me because it states the maximum a Mac can output over USB is 900mA (if I'm reading it correctly), yet if I plug an iPhone or iPad into my 2015 iMac I get the following in System Profiler:

Current Available (mA): 1000
Current Required (mA): 500
Extra Operating Current (mA): 1600
Sleep current (mA): 2100​
Yeah same experience here with my Macs. I read that too and was like, wait a minute? lol. So I just added: Some manufacturers do more. I know mine does, lol.
 

C DM

macrumors Sandy Bridge
Oct 17, 2011
47,557
16,059
I was curious as to what new things people are saying I clicked the link..... and read the expert chemists.

Suggestion: Don't go the deep end, stop reading how you should charge, keep doing whatever is convenient. Spend $$money to make your life easier and not further add stress and obsessions.
Ultimately that seems to be the better of way of going about it for most people.
 
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