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Berthacrowley

macrumors member
Original poster
Sep 29, 2015
97
46
Nahant, MA
Since getting my 6S+, I've noticed it's very slow to charge when hooked up to the charging cable via my work PC's USB port. With the phone screen off, in 30 minutes it only charged 7%.

By comparison, when plugged into a wall outlet at home or into my car charger, it will charge at least triple that amount in the same time.

In fact, even though it's plugged into my computer right now, the battery percentage is slowly dropping during use, even though it's plugged in! This never happened with my 5S which is why I'm curious. Does the 6S+ use that much more power? Or is my cord? Or is it my piece of crap work PC?

At home I use the OEM Apple cord, in my car is a Radio Shack cord & at work it's an Anker cord (both the Radio Shack & Anker cords are Apple certified).

I plan to bring in a power brick from home tomorrow to see if it'll charge faster, I'm just curious as to why it's SO much slower now.
 
I've always found charging to be slower when plugged into the USB port on my computer. Wall charging is much faster.
 
It all depends on how many amps are delivered by your computer. Many only provide 500mA, instead of 2.1A by a newer iPad charger. I wouldn't expect it to be losing power while plugged in, but what "use" are you putting it to?

C
 
Charging via a computer or vehicle USB port is considerably slower than if using the wall charger. It's because they put out different amounts of juice. A USB port is for feeding very low power devices and you'll find that if you're doing something on your phone at the same time as charging via a computer port, the battery will barely charge at all.
 
It all depends on how many amps are delivered by your computer. Many only provide 500mA, instead of 2.1A by a newer iPad charger. I wouldn't expect it to be losing power while plugged in, but what "use" are you putting it to?

C
Usually just browsing/twitter/Instagram but I do keep my screen brightness at 100%. If I'm browsing for 15-20 minutes (during my breaks of course!) while the phone is plugged into the computer, I lose 1-2% battery.

Interesting, thanks for the info guys! I knew a computer would be a little slower than a wall but I didn't realize it would be quite this much slower. As I said, I didn't notice this much of a difference on my 5S but maybe I'm just using the 6S+ more since it's shiny & new.
 
Charging via a computer or vehicle USB port is considerably slower than if using the wall charger. It's because they put out different amounts of juice. A USB port is for feeding very low power devices and you'll find that if you're doing something on your phone at the same time as charging via a computer port, the battery will barely charge at all.

It depends entirely on which computer and which car charger. Blanket statements are incorrect, in this case.

C
 
Usually just browsing, but I do keep my screen brightness at 100%. If I'm browsing for 15-20 minutes (during my breaks of course!) while the phone is plugged into the computer, I lose 1-2% battery.

Interesting, thanks for the info guys! I knew a computer would be a little slower than a wall but I didn't realize it would be quite this much slower. As I said, I didn't notice this much of a difference on my 5S but maybe I'm just using the 6S+ more since it's shiny & new.

What computer do you have?

C
 
It all depends on how many amps are delivered by your computer. Many only provide 500mA, instead of 2.1A by a newer iPad charger. I wouldn't expect it to be losing power while plugged in, but what "use" are you putting it to?

C


Well apparantly it takes around 3 hours to fully charge using the mains charger (2.1A), and you get about 9 hours active use from a full charge. So if a computer USB only gives you 500ma (a quarter of the mains charger), it could take 12 hours to fully charge - which is longer than it lasts on a full charge. So it is feasible that it could drain faster than it can charge.
 
I use ASUS AI Charger downloading from
here

If your motherboard is supported, charging speed will increase up to 2A. Having USB3 port is an added advantage. iPad no longer shows "Connected but not charging" message.

Mysteriously, the program is from 2010 but works flawlessly even on Windows 10. It just sits quietly under Windows system tray but becomes active once a compatible charging device is detected and has started charging.

Love it.
 
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It's an older IBM tower. I don't have any of the specs on it because work has disabled access to anything on the machine that isn't Outlook or our internal work software. Can't get into any kind of system info.

Well, there's your problem... :) Time to break the computer!

It's likely only putting out 500mA, with is less than 25% of the 2.1A that the iPad type wall plugs can put out. So yes, it's likely your piece of crap work PC. Not computers in general.

C
 
I use ASUS AI Charger downloading from
here

If your motherboard is supported, charging speed will increase up to 2A. Having USB3 port is an added advantage. iPad no longer shows "Connected but not charging" message.

Mysteriously, the program is from 2010 but works flawlessly even on Windows 10. It just sits quietly under Windows system tray but becomes active once a compatible charging device is detected and has started charging.

Love it.
I used to use that app as well, sort of neat being able to charge your iPad even with an old USB2 port. Not needed now as I use the high power USB port on my iMac. Great app anyways!
 
Well apparantly it takes around 3 hours to fully charge using the mains charger (2.1A), and you get about 9 hours active use from a full charge. So if a computer USB only gives you 500ma (a quarter of the mains charger), it could take 12 hours to fully charge - which is longer than it lasts on a full charge. So it is feasible that it could drain faster than it can charge.
Isn't the typical iPhone charger 1A though?
 
In vehicle I use a 2.1a charger that plugs into the 12v cigarette lighter, at home I use the 2.1a iPad charger and at work my laptop has two 2.1a usb slots.

Even the power brick I use has a 2.1a slot. Never understood why people still use anything but 2.1a chargers.

Using the 2.1a chargers it takes no time at all to charge
 
Most Usb ports only deliver 500mah. The OEM charger is 1a, double that. The ipad charger is 2.1 amps or double that (4 times the USB port).

My 6S charges super fast on the ipad charger and super slow on usb.
 
Isn't the typical iPhone charger 1A though?

Is it?? Why aren't they shipping with 2A chargers - no wonder they get such rubbish charging times. Can you safely use an iPad charger on an iPhone? I have a couple in the house.
 
Is it?? Why aren't they shipping with 2A chargers - no wonder they get such rubbish charging times. Can you safely use an iPad charger on an iPhone? I have a couple in the house.
You can use an iPad charger. Traditionally they ship the smaller iPhone charger which is 1A. The charge times are fairly typical, and and until iPhone 6 the phones couldn't charge at a faster rate anyway.
 
So just to reiterate what everyone already knows, I brought my power brick in to work today. To have the most accurate comparison, I ran the phone down to 60% battery before plugging it in for exactly 30 minutes, which is what I did yesterday when testing the charging speed via my computer's USB.

Yesterday, after 30 min of charging via the computer with phone screen off, it went from 60% to 67%.

Today, after 30 min of charging via the wall with the phone screen off, it went from 60% to 77%, so more than double. And in the 3 minutes it took me to type this, still plugged into the wall with the screen at full brightness, it's jumped to 80%.

Lesson learned: wall charge forever (at least until work updates our computers!)
 
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