iPhone 16 Pro Max 80% Charge Limit: One Year Later, Was It Worth It?

[BigMcGuire]

My 17PM is at 100% health at 207 cycles using the 80% charge limit (and almost never going below 20%). 99.9% magsafe charging (one of my bedside table for overnight charging, one in my cars for car charging, one at my desk at work for work charging). I basically only plug it in if I need to FAST charge for some reason... which has probably happened less than 10 times.

It spends a lot of it's life at 80%, between the overnight charging and work charging.

I think this is where the 80% rule benefits the most - those of us who leave our phones constantly plugged in and/or on a charger. I work a desk job during my day job and outside of that my phone is constantly on a charger (at night/at home) - so sitting at 80% is far more beneficial than at 100%.

Those that use their phones off of a charger - there is a benefit of 80% charging but not as much as those of us who have our devices spend a lot of time on the charger.

There are many variables.

 

[Obioban]

I also have a launch day Apple Watch Ultra 2 that I've been charging to ~80%. It doesn't have a cycle counter, but most days it uses ~55% of a cycle (charged entirely during showering/teeth brushing, worn overnight and the rest of the time). Given that and the ~1000 days of service life, I'd estimate it's at ~550 cycles.

Easy to charge the Ultra 2 to ~80%-- it charges FAST to 80%, then really slows down. So, charging it while taking a shower and brushing my teeth in the evening basically always gets it to 80-83%, regardless of where it starts. I then wear it overnight and throughout the next day, and it's always 25-30% SoC the next night when I put it on the charger. Once every month or 2 I try to give it a 100% charge (leave it on after my shower till bed time) so it can do battery conditioning.

95% indicated battery health at ~550 cycles. Which, I think may be the first step down from 100% on the Watch? I never saw it at anything other than 100% before it went to 95%.

With apple dropping WatchOS support for all the 7nm watches at the same time, decent odds they'll do the same for 5nm watches-- so I figure I have at least 3 more years of software updates for this, plus some years of security updates. I'll do my next watch hardware upgrade at the first node shrink after WatchOS updates end... so this thing will likely end up getting 7-8 years of use. 3 years in, I'm pretty confident I shouldn't have any battery capacity issues in that time period. Really, since I have buffer at the top end and bottom end, the only thing that would require me to change behavior is if the charging rate significantly degrades at some point.

 

[Obioban]

I have also have 3 Tesla PowerWalls with a 80% charge limit, plus a Home Assistant automation that charges them to 100% 90 days since the last 100% charger (for conditioning, and not just every 90 days because sometimes Storm Watch charges them to do a 100% charge in preparation for a storm).

Here is their capacity over time. November is when I used Home Assistant to turn on a 80% charge limit on them. The 3 lines are the 3 different batteries.

You can argue that it's not useful on a phone, but Powerwalls are $14,000 each, and I have 3-- I'd like them to last! Plus, I only need ~20% on days we don't have grid outages, to cover my 4 hours of peak power rates.

In the interest of fairness, I also used Home Assistant to slow the rate of charging by 60%. So long as they can get a "full" charge during my super off peak rates (midnight-6am), I don't care how fast they get there-- and slower charging should also be better for battery longevity.

It's pretty dramatic, though-- look at the capacity drop off before/after the 80%/slow charging changeover (November)!

 

[WebHead]

My 13 mini's battery capacity has dropped below 80% after just over four years, so I can confirm my "only charge to 80%" experiment is a failure. A lot of wasted effort over that time!

Will upgrade the battery and just leave it on the charger from now on

 

[Sosab123]

80% is super nice for casual users. Especially if your iPhone isn't your only device. That's one of the main reasons I like using both iPhone and iPad Mini together as it help cut down on charge cycles across both devices.

I got my iPad Mini 7 and 17e in May, it is now august and I only have 20 charge cycles on Mini, and just 8 on my iPhone 17e cause I don't use it all that much. Glad I went with 17e instead of Air cause the battery life is worth it. Casual use gets 2+ days without really needing to plug it in. I have a few of those Samsung wireless chargers with the fan built in them.

 

[Obioban]

My 13 mini's battery capacity has dropped below 80% after just over four years, so I can confirm my "only charge to 80%" experiment is a failure. A lot of wasted effort over that time!

Will upgrade the battery and just leave it on the charger from now on

That phone doesn’t have the charge limit feature?

 

[Und Eser]

Been charging my 16 Pro to 80% for about a year, phone's 21 months old and battery's at 96% for 242 cycles.

Decided to stop playing this daft battery-babying game, its a consumable item which Apple has unsurprisingly seen fit to turn into a profit-generating inconvenience for their customers. 16 Pro needs a full charge to be used to its full potential for any worthwhile time anyway IMO.

My 4 1/2 year-old Apple Watch 7 Series, now excluded from any further software upgrades, is currently reporting 89% battery capacity. Might indicate battery life being somewhere lower on the list of things to get undergarments in a twist about than OS support...