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macrumors newbie
Original poster
Oct 28, 2012

So, I’ve seen many posts saying using new official battery case for X/S (Max) decreased people’s battery health, like 3-5%.

Can people using this product confirm if it’s true in their case?

I really wanna get one but I’m a bit worried. My battery is already at 90% health and I don’t want it to decrease any further.


macrumors newbie
Mar 5, 2019
I’ve owned the battery case since the day it came out, so a little over a month now. My iPhone X battery has stayed at 87% since October or November, and the case hasn’t changed that.

I’m not a professional in this matter, but I don’t think the case is harming the phone.


macrumors 6502
Jul 27, 2010
Have had for my XS Max since day 1 and my battery health has remained at 100%.


macrumors 6502a
Oct 24, 2018
I posted this in the other thread about the Smart Battery Case, but I put the case on my phone on February 19, and I took it off yesterday (February 28); my battery health dropped to 97%. I bought the XS Max on October 2, 2018, and the battery health was at 100% up to that point.


macrumors G4
Sep 6, 2002
I really wanna get one but I’m a bit worried.
Being in constant fear is a sad way to live. If you want or need longer life because you're away from power, get either a power bank or a battery case. End of story.


macrumors 603
Aug 19, 2017
I’ve found the battery health reading on the native app is hit or miss. Mine says my X is a 97% yet when plugged into coconut battery it reads 99%. I’d say it’s an estimate at best..


macrumors G3
Oct 18, 2011
Still 100% here on my launch day XS Max and I've had the smart battery case since launch day as well.


Sep 16, 2014
I stopped using the 2 I bought when both phones I am using XS and XS Max took 3% drops in a month. Definitely not worth it killing the internal battery. Both were at a 100% prior to using the cases.


macrumors newbie
Original poster
Oct 28, 2012
Thanks so much for all your answers guys. It seems mostly people with new batteries around 95-100% see decrease in battery health. I’ll risk and get one for my 90% battery iPhone X, let’s see if it drops any further.


macrumors member
Sep 11, 2014
I have an iPhone XS Max that I purchased at launch. After 6 months, the battery health dropped from 100% to 99%. I had the case for 2 to 3 weeks and my battery health has dropped to 97%. I was using the smart battery case 24/7. I am going to stop using it now and only use it if I absolutely need it. I have 5 kids and my phones get passed down multiple times so I would rather preserve battery health.
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manu chao

macrumors 604
Jul 30, 2003
So, I’ve seen many posts saying using new official battery case for X/S (Max) decreased people’s battery health, like 3-5%.
If anything, a battery case will slow the battery degradation of the internal iPhone battery because it significantly reduces the number of charge cycles the internal battery goes through (in an approximate way, instead of charging your phone battery twice a day, with a battery case, it might only get charged once per day because for the first half of the day it is essentially plugged into a power source, the battery case). Sure, any phone case, in particular a thick one, will make heat dissipation harder and thus might slightly affect the battery health.

But keeping your phone plugged in at 100% battery capacity for roughly the first half of the day (which is what a battery case does) will have practically no measurable effect. You'll very likely still exercise the battery every day (if you were to get by with only the case's battery for anything close to a full week, you'd have no real reason to actually use the battery case daily). If keeping the phone plugged in at 100% battery for part of the day would be detrimental, people would start recommending to not charge your phone overnight (but either in the morning or evening, depending on your schedule). What might happen is that you much less frequently (almost) completely deplete the iPhone's internal battery. But if you are worried about that, just intentionally deplete it once or twice a month.

In regard to the reported 2 to 3% drop in battery capacity, that in all likelihood is completely incidental (ie, due to other reasons that just happened to occur at the same time people started using the battery case, from normal degradation that just happened to pass some thresholds that made it visible on the percentage scale to new OS versions that slightly changed how things are calculated). It is naturally also possible that the different discharge-charge pattern simply triggered an artefact in the calculation of the battery capacity that is largely artificial without reflecting any real decrease in capacity.
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