Battery Life

[charlesxy]

Is there truth to the notion that one can preserve a battery longer if it not charged and maintained all the way to 100% all the time?

Is also true that the it helps to let the battery die every once and awhile?

If true, why so?

Thanks.

 

[Tim1954]

Google battery doctor and you'll get the full story.

 

[chanchan05]

Source is from Battety University website:


The gist is, basically, batteries work by ion movement, and like a machine, these ions wear out over time due to use. And similar to machines, heavy use wears them out more. You're more likely to break an engine by running it for 1 day at max rev, than running it over a month at half capacity. The smaller the depth of discharge, the lower the wear. Lab tests have concluded that when you constantly discharge from 100 to 0, it allows you betwrrn 300-500 charge cycles before it starts to break down and not hold charges. More specifically, when you reach that magic number your battery can only hold 75% of it's original charge. That's typically 1-2 years of use if you charge once a day. And heavy abusers charge more than once a day, so that decreases the time span to however many weeks it takes them to reach 500 charge cycles. Now, the increase in charge cycles is exponential, not arithmetical. So a depth of discharge to 50 before recharging will not give you 600-1000 charges. Rather it will give you 1200-1500 charge cycles. Mathematically, draining a 3600mah to zero for 300 charges gives you 1080000mah to burn through however short your battery life will be. On the other hand, using only 50% of the battery before recharging gives you 2160000mah to burn through before it expires after at least 1200 charge cycles. In other words, it stored twice more power for you to use. If you say, charge once every 24hrs, going always from 100 to 0 gives you at least 300 days. Recharging twice a day at 50% gives your battery at least 600 days of use before battery capacity deteriorates noticeably. Discharging to 75% before recharging actually gives you 2000-2500 charge cycles, making it even longer. Basically the point is, always plug the phone in when given the chance. Don't wait for 50%, or whatever. 40% is an arbitrary number actually, not sure why it's chosen. Also, this is why one of the choices to auto activate power saving in the S7 is at 50%, so that it keeps the battery up as close to 50% as possible when you get the chance to plug in.
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As for charging to 80%, this is because partial charge is better than full charge for lithium ion batteries. The ions are placed on stress to hold charges. Maximum stress is at 100% charge. And like everything else, stuff tends to break more. So not running it to 100% all the time will reduce overall stress experienced and increase the time before deterioration occurs. Personally I charge to 90%, and discharge to 40% or above. That's a 50% depth of charge, so that's good for up to 1500 charge cycles, plus whatever number of cycles the decrease in max stress gives me.

However, note that environmental temperatures also play a role in battery longevity.

 

[charlesxy]

Thanks for all the info. Much to digest, to be sure.

So, basically, there is no need to charge to 100% when I leave home every morning?

I used to charge my S3 before going to bed each night because it would take all night to charge. However, with my new 7, it doesn't take all night. I guess then I should simply charge to 90/100 and discharge before sleeping. When I wake up the next day, the battery is only so slightly drained. But, I feel it is enough to make it through the day. With the 3, I would keep it charged at work. However, to make my new s7 and it's battery last, it is therefore suggested I keep it discharged at work?

Thanks.

 

[chanchan05]

Just don't let it go below 40.

 

[charlesxy]

So, 40 and below is no good for the battery? Once again, Is this because it takes a lot out of the battery to charge from below 40 to 90?

Thanks.

 

[chanchan05]

It's 10% below that has potential to damage the battery. But you want to keep it above 40 to increase lifespan.

 

[charlesxy]

I see. Thanks. And, is best to keep from 80 to 90 on the other end>

Is 100 too much for the battery?

I assume therefore that there is no truth to the fact that one should let the battery die every once and awhile?

 

[chanchan05]

100 isn't bad. But not going to 100 is better.

Letting the battery die was true 15 years ago with nickel batteries. We are using different batteries now.

 

[charlesxy]

Got it. Thanks.

In addition to my 7 that I have for personal reasons, I've also been issued an iPhone 5 for work use. I hardly use that iPhone, however. But, I did notice that the battery life on the iPhone is comparable, if not better than the galaxy s7. Is this in part because the screen on the iPhone is much smaller than the s7? Thanks.

 

[PauloPImenta]

I have my S7 for more than 1 year. I notice battery is getting worst. I have bought a mophie case that charges wireless and the combo gives me a full day. I use to charge every night on my Samsung pad. I do not understand why they are manufacturing devices thinner instead of caring more about larger batteries. Any device should last at least a day so we don't need for care about battery all day. I have acquired for USD 250 a Xiaomi redmi note for holidays so I can use two sim cards, and the battery last me one and half days using it more intensely than the S7 as I'm watching a lot of netflix. To be honest, I think I will not buy a top phone and waste more than USD 750 as long they don't increase battery capacity. This redmi has a 4000 battery capacity.

 

[chanchan05]

Got it. Thanks.

In addition to my 7 that I have for personal reasons, I've also been issued an iPhone 5 for work use. I hardly use that iPhone, however. But, I did notice that the battery life on the iPhone is comparable, if not better than the galaxy s7. Is this in part because the screen on the iPhone is much smaller than the s7? Thanks.

Smaller screen, less stuff running since iPhone heavily restricts background processes, also screen tech, and features. For example, the Always On Screen feature alone eats up almost 2% per hour when active. I've tested this where my phone runs at 2.5% per hour idle with that feature on, and just 0.6% per hour with it off.

 

[CWinkler]

I don't use my phone much during the day while at work. I've gotten into the habit of putting it face down while not in use, thinking that will fool it into thinking it's in a bag so the display will stay dark. I can still hear the notification sounds, so know if I need to pick it up to check on anything. I can often go 9 hours and still be at 70% with this approach.

 

[chanchan05]

I don't use my phone much during the day while at work. I've gotten into the habit of putting it face down while not in use, thinking that will fool it into thinking it's in a bag so the display will stay dark. I can still hear the notification sounds, so know if I need to pick it up to check on anything. I can often go 9 hours and still be at 70% with this approach.

Curious as to why not turn off the AOD if you use it like that? Won't it be just easier to turn off AOD so you can have it face up and see the LED?

 

[CWinkler]

Curious as to why not turn off the AOD if you use it like that? Won't it be just easier to turn off AOD so you can have it face up and see the LED?

I like to have it available when I do want to use it. No big deal to put it face down.