iPhone battery health and charging practices — looking for official guidance

I 100% concur with LD150. There's no need to overthink this. The phone is designed to manage its battery.

deedy_89 wrote:

I chose this model simply because I don’t like large phones, and at the time it was the smallest new iPhone available.

The smaller the phone, the smaller the battery. And yes, over time the battery capacity declines. Check yours in Settings>Battery>Battery Health>Maximum Capacity. It's its 80% or below, you need a new battery. It sounds as if you may be due. Two to three years is pretty standard for battery life.

Despite being a light user, the battery performance has declined noticeably. I don’t use Instagram, TikTok, Snapchat, or similar apps. I don’t game, I don’t do heavy video streaming, and I don’t use the camera constantly. My usage is limited to calls, messages, WhatsApp, Spotify, Notes, and Files. Even with this relatively modest usage, the phone now requires charging more than once per day.

That sounds like an aging battery to me.

Lately, I’ve also been keeping the phone in Low Power Mode most of the time in an attempt to extend battery life, and I’m unsure whether this is considered a good long-term practice or simply a short-term workaround.

It won't hurt anything. And, because you're using less power, the battery will last a bit longer.

Over the years, I’ve encountered a lot of conflicting advice, including recommendations such as waiting until the battery drops below 20% and then always charging to 100%, and I’m unsure whether this guidance is still valid for modern iPhones.

No, that is not valid advice for modern lithium-ion batteries. In fact, 20% is about when you should plug it in. Letting it go below that is not ideal. How much you charge it is really a matter of how much time you have.

You may want to look as this overview. It has good advice and links to Apple's offical documentation.

When to charge your iPhone or iPad - Apple Community

The Adaptive Power feature on new phones is frankly, amazing, by the way.

GeeZ06 wrote:

Hello deedy_89,

The more charge cycles your battery completes the faster it ages. Charging just to 80% nightly has worked best for me keeping my charge cycles to a minimum on my iPhone 17PM. How you use your iPhone should determine if you want to charge nightly to 100% with optimize charging turned on. See if this article on Lithium batteries is helpful to you.

Batteries - Why Lithium-ion? - Apple

Charging cycles (ie equivalent full charge cycles) will be the same whatever you do with the Charge Limit placebo. Charge cycles reflect your battery usage when off charge. No more, no less

The basic issue is the last 20% charge (from 80% to 100%) produces more heat than charging from 60% to 80%. The topping off cause chemical stress, even though it’s being trickle charged. Trickle charging mostly prevents lithium plating, but not entirely. But holding a 100% charge is harmful to overall battery life. Therefore, optimized charging is highly recommended if charging to 100%.

I’m sure Apple has the facts to backup their recommendations. After all, hundreds of millions of iPhones share analytics with Apple every year. Recommendations are based on science and facts gathered from millions of users. This makes for very reliable recommendations.

The second consideration is what is worse for overall battery health, charging to 100% or discharging below 20%? While repeatedly discharging below 20% risks damage to the copper electrodes, prolonged or continual charging to 100% is again more damaging because of the long term risks the heat and lithium plating that occurs over extended periods.

However, at the end of the day, an iPhone is almost useless if its battery is depleted and not functioning as intended. A discharged battery imposes risks beyond just battery life. Phones are needed for personal safety, medical emergencies etc. and are an integral part of our modern lives. You must make choices based on the needs of the iPhones owner and those that depend on him/her. I do not choose my charging routines based on what’s best for the battery. I choose what’s best for me and for those that depend on me.

There will be a number of opinions in this Pandora's box! And you didn't evaluate considerable decline.

Here is mine.

Charge every night, all night, to 100% with optimised charging on. Charge limit is merely a placebo.

If a light user has to charge more than once a day there is a rogue app installed.

Keep the phone out of hot and sunny conditions like on a car dashboard.

In the end it is usage that ages batteries.

Hello deedy_89,

The more charge cycles your battery completes the faster it ages. Charging just to 80% nightly has worked best for me keeping my charge cycles to a minimum on my iPhone 17PM. How you use your iPhone should determine if you want to charge nightly to 100% with optimize charging turned on. See if this article on Lithium batteries is helpful to you.

Batteries - Why Lithium-ion? - Apple

GeeZ06 wrote:

The more charge cycles your battery completes the faster it ages. Charging just to 80% nightly has worked best for me keeping my charge cycles to a minimum on my iPhone 17PM.

LD150 is 100% correct on this. If your phone is at 30%, and you charge it to 80%, that's half a charge cycle. It doesn't "save" anything in the long run because you have to charge your phone again sooner than if you charged it to 100%.

Use Adaptive Power mode and Optimized Battery Charging with the 100% limit, and don't worry about it. Charge when you can or when you need to. The phone's algorithm will do a better job than you ever could at managing the battery. It has more information.

"Over the years, I’ve encountered a lot of conflicting advice, including recommendations such as waiting until the battery drops below 20% and then always charging to 100%, and I’m unsure whether this guidance is still valid for modern iPhones."

That advice was for NiCad and even NiMh batteries to avoid charge memory.

I have an SE3 which I use as an Apple Music server overnight (tinnitus!) In the morning it is at about 80%. It goes on charge every morning, optimised, til the evening.

My wife's iphone SE bought at the same time is hardly used. It drops to 85% by evening by just being an iphone. That's what an idle phone uses. It goes on charge all night every night, optimised, til morning.

After a year battery health on both phones is 98%

It is usage, not charging regime, that affects ageing.

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looking for official guidance

Could you please clarify what you mean be "official"?

Would Apple qualify as "official", or would an iPhone expert qualify as well?

Please remember that guidance from different sources is going to vary, so you are going to be faced with having to guess which "official" advice you want to accept.

What I do know is what works best for me. Optimized Battery Charging. Connecting the phone to the power supply at night and leaving it connected all night....every night. Ignoring Charge Limits.

Speaking of Charge Limits, my opinion is that they are more of a gimmick than anything else, but that might be another discussion.

Bob Timmons wrote:

What I do know is what works best for me. Optimized Battery Charging. Connecting the phone to the power supply at night and leaving it connected all night....every night. Ignoring Charge Limits.

Speaking of Charge Limits, my opinion is that they are more of a gimmick than anything else, but that might be another discussion.

It seems to be the opinion of quite a few, if not most, of the regular posters. Especially the charge limits part!

IdrisSeabright wrote:

Bob Timmons wrote:

What I do know is what works best for me. Optimized Battery Charging. Connecting the phone to the power supply at night and leaving it connected all night....every night. Ignoring Charge Limits.

Speaking of Charge Limits, my opinion is that they are more of a gimmick than anything else, but that might be another discussion.

It seems to be the opinion of quite a few, if not most, of the regular posters. Especially the charge limits part!

Gimmick, Placebo, Sop, Snake Oil...

LD150 wrote:

Gimmick, Placebo, Sop, Snake Oil...

I'm going with "placebo." So many people want to monkey with and micromanage their batteries that Apple decided to give them a harmless setting to play with. It gives them a sense of control.

By the way, Apple Certified experts generally don't visit here, we are all users.

You’re welcome and I hope you have a great weekend!