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Wirenut

macrumors regular
Original poster
Nov 6, 2016
198
94
I have a question about charging my iPhone 6S, in which I just got a new battery and I'd like to see how long I can use this phone for.

I find myself at my desk for an hour or so at a time, and often my phone will have 30-40% charge. I know that I won't be at my desk long enough to fully charge the phone, so I don't plug it in. The same for trips in the car.

I was under the impression that when charging a phone it was best to fully charge it... that charging it only to 80% or so isn't good for the battery. Is that true?
 

Adam.Kb2Jpd

macrumors member
Jan 20, 2018
69
16
I have a question about charging my iPhone 6S, in which I just got a new battery and I'd like to see how long I can use this phone for.

I find myself at my desk for an hour or so at a time, and often my phone will have 30-40% charge. I know that I won't be at my desk long enough to fully charge the phone, so I don't plug it in. The same for trips in the car.

I was under the impression that when charging a phone it was best to fully charge it... that charging it only to 80% or so isn't good for the battery. Is that true?

Good question. You have a new battery and it hasn't been broken in. It will have to endure a series of charges and discharges to properly keep a charge.

If your charge goes down to 20% charge it. It doesn't have to be at 100 85 to 88 will do. You might also to turn on the battery precentage on the screen.

Once charged, remove it from the charger so the battery won't heat up.
 

JPack

macrumors G4
Mar 27, 2017
11,478
20,798
I was under the impression that when charging a phone it was best to fully charge it... that charging it only to 80% or so isn't good for the battery. Is that true?

No, the opposite is true. Full charges and discharges are poor for battery health. Ideally, you do not want to reach the extremes, i.e. fully charge or discharge a battery. If possible, follow the 80/20 rule of charging up to 80% and avoiding discharge levels below 20%.
 

Wirenut

macrumors regular
Original poster
Nov 6, 2016
198
94
Just use you phone and enjoy.
That's how I have been doing it for years, and I find myself with a very low battery at bad times so I am looking for the best way to charge it.
[doublepost=1522498913][/doublepost]
No, the opposite is true. Full charges and discharges are poor for battery health. Ideally, you do not want to reach the extremes, i.e. fully charge or discharge a battery. If possible, follow the 80/20 rule of charging up to 80% and avoiding discharge levels below 20%.
So even if I could leave it on the charger longer, it's best to unplug it at 80%?

I never heard that. That would be easy to do since going from 20% to 80% goes really fast. It's that last 20% that drags on for an hour.
 

JPack

macrumors G4
Mar 27, 2017
11,478
20,798
So even if I could leave it on the charger longer, it's best to unplug it at 80%?

I never heard that. That would be easy to do since going from 20% to 80% goes really fast. It's that last 20% that drags on for an hour.

This is standard operating practice with Li-ion batteries.

If you look at Tesla, they recommend this 80/20 rule to maximize battery health and available cycles. The software default avoids charging to 100%. Tesla batteries cost tens of thousands of dollars and have an 8 year warranty. It’s less of a concern for Apple because iPhone warranty is 1 year and the battery costs less than $5.

Even iOS 11.3 acknowledges this with the “iPad Charge Management” feature. It avoids charging to 100% for long periods of time. If a full charge were not harmful, this feature wouldn’t be necessary.
 
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Wirenut

macrumors regular
Original poster
Nov 6, 2016
198
94
This is standard operating practice with Li-ion batteries.

If you look at Tesla, they recommend this 80/20 rule to maximize battery health and available cycles. The software default avoids charging to 100%. Tesla batteries cost tens of thousands of dollars and have an 8 year warranty. It’s less of a concern for Apple because iPhone warranty is 1 year and the battery costs less than $5.

Even iOS 11.3 acknowledges this with the “iPad Charge Management” feature. It avoids charging to 100% for long periods of time. If a full charge were not harmful, this feature wouldn’t be necessary.
Thank you sir.
 

mikzn

macrumors 68040
Sep 2, 2013
3,005
2,290
North Vancouver
I find myself at my desk for an hour or so at a time, and often my phone will have 30-40% charge. I know that I won't be at my desk long enough to fully charge the phone, so I don't plug it in. The same for trips in the car.

I was under the impression that when charging a phone it was best to fully charge it... that charging it only to 80% or so isn't good for the battery. Is that true?

Everyone has different priorities - I use my phone at my computer and in the car like you mention (iPhone 6) - I always charge as much as I can because I never know how long I will be using it with out charging.

Perhaps the cycle count iand battery capacity is a more useful gauge - coconut battery is a great tool for this and you can track the history of the design capacity against the current full charge - great little software for Mac's and iOS devices.
 

now i see it

macrumors G4
Jan 2, 2002
10,153
21,061
Whenever you're near power and it's convenient, plug the phone in to get the battery up to 80%. Even if its at 65%. Since keeping the max charge at 80% will obviously reduce your max run time, you want to keep it near there so when you do have to unplug you'll have some reserve.

On the other hand, if you know you'll be away from power all day and you'll be using the phone, charge it up to 100%. You'll need all the power you can get.

But ideally (and more of a hassle) bring a battery pack with you so you never have to charge it up to 100%. A 100% charge to the battery is poison to it (low grade poison).

Or...
Just forget all the battery care hassle & keep it plugged in to 100% whenever convenient- and when the battery wears out in 1-1/2 to 2 years, just get another one from Apple. No big deal.
 

Newtons Apple

Suspended
Mar 12, 2014
22,757
15,250
Jacksonville, Florida
That's how I have been doing it for years, and I find myself with a very low battery at bad times so I am looking for the best way to charge it.

Just plug it in before you go to bed and repeat each night. If your battery does not make it though the day, you either have a bad battery or are living on your phone. Apple did I not design the phone for all day constant use. The battery is designed for average use but the average user.
 

Wirenut

macrumors regular
Original poster
Nov 6, 2016
198
94
I am getting conflicting information. A few people say to only charge it to 80%. Another person says it's fine to charge it to 100% by leaving it plugged in all night, every night. And another person said that is bad to leave it plugged in because the battery will heat up.

If for nothing other than curiosity's sake, I'd like to know which one is accurate.
 

Adam.Kb2Jpd

macrumors member
Jan 20, 2018
69
16
I am getting conflicting information. A few people say to only charge it to 80%. Another person says it's fine to charge it to 100% by leaving it plugged in all night, every night. And another person said that is bad to leave it plugged in because the battery will heat up.

If for nothing other than curiosity's sake, I'd like to know which one is accurate.

Read this:

https://www.apple.com/batteries/maximizing-performance/

from the Horses mouth: Apple. Reread and then decide how you wish to proceed.
 

tonybarnaby

macrumors 68020
Dec 3, 2017
2,363
1,682
Just so everyone knows, there is no way to calibrate an iPhone battery. This is straight from Apple themselves.

I had bad battery ocd until recently. Now I charge overnight and don’t worry. It feels much better than babysitting a stupid battery.
 
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Wirenut

macrumors regular
Original poster
Nov 6, 2016
198
94
Just so everyone knows, there is no way to calibrate an iPhone battery. This is straight from Apple themselves.

I had bad battery ocd until recently. Now I charge overnight and don’t worry. It feels much better than babysitting a stupid battery.
I normally just let it sit and charge and forget it too. Like Ron Popeil, set it and forget it :p

The question that I had that made me ask today was whether it's OK to let it charge when there won't be enough time to fully charge it.

Now I am just interested in the specifics out of curiosity, since there has been so many different things posted.
 

Newtons Apple

Suspended
Mar 12, 2014
22,757
15,250
Jacksonville, Florida
Thanks for the link.

I didn't see anything there saying that you shouldn't leave it plugged in after it is fully charged because the battery will heat up.

You will get a 100 answers on batteries. Still so many old wives tales.

Yours will not heat up after charged. The charging system will simply turn off.
 

1050792

Suspended
Oct 2, 2016
2,515
3,991
Sorry but unfortunately there's no correct way to charge lithium batteries besides not letting it completely discharged for a LONG period of time. Lithium batteries work with cycles so you can charger whenever you want for how much time you want or need. No rules here.
 

MacDawg

Moderator emeritus
Mar 20, 2004
19,824
4,518
"Between the Hedges"
I charge overnight, every night, regardless of how much charge it has when I go to bed
At work, sometimes I leave it on the wireless charger and pick it up when I leave my desk
I never pay any attention at all to my phones charge, I just use it and charge as I have opportunity

And I am certainly not going to set an alarm at night to unplug my phone at 80% to prevent it from reaching 100%

I've had my X since November and I just checked the Battery Health for this thread - 100%
 

Wirenut

macrumors regular
Original poster
Nov 6, 2016
198
94
In order to charge my phone at night I would need a 6 foot charging cord. I don't know why Apple only includes a 3 foot cord, 6 foot has been the standard length for power cords for 60 years.
 

MacDawg

Moderator emeritus
Mar 20, 2004
19,824
4,518
"Between the Hedges"
In order to charge my phone at night I would need a 6 foot charging cord. I don't know why Apple only includes a 3 foot cord, 6 foot has been the standard length for power cords for 60 years.

My phone is in a different room from me on my desk at night when I am in bed
On a wireless charger, plugged into an extension cord

Lots of options here
 

now i see it

macrumors G4
Jan 2, 2002
10,153
21,061
Charging a Li Ion battery is a trade off between shooting for ultimate battery life span (attainable charge cycles, not daily capacity) and convenience.

This graph shows it all.
image.jpeg


No phone manufacturer is going to recommend to their customers to charge the phone to 75% then unplug it, then plug it back in at 65% because that's rediculous and nobody would do it - though doing so would give the battery the longest life span.

So pick your evils. If you lived out in the boonies or Mars and getting a battery replacement is near impossible- then following one of those charge profiles above would give you the longest battery life.

If you lived next to an Apple Store & don't mind spending $80 every 1-1/2 to 2 years on a new battery - just plug in the phone & forget about it - and use it each day until it's depleted to zero. It's just a battery.

But any way you choose to use your battery, it's ALWAYS best to plug in even for a couple minutes if you're below 80% if you've got the chance. Using an iPad charger also really speeds things up.
 
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