iPhone 6(S)/Plus iPhone 6S sudden battery drain

[Candlelight]

I've had my iPhone 6S for a couple of years and it's been very reliable. I've kept in on iOS 9 as I've never needed to up upgrade it, battery usually gives me 70-80% full when I leave work at 5pm without having needed to charge it throughout the day.

Then in the last 10 days it started draining a lot faster. I would barely make it to 3pm before it would completely run out. I bit the bullet and upgraded to iOS 11.3 (which is just horrible FWIW) and that didn't fix it. Did a complete backup and restore and that didn't fix it. I changed it for a new battery three days ago and now the new battery is down to 47% after four hours coming off the charger.

I have disabled location services, background app refresh, fancy iOS 11 animations, anything that might drain the battery. I have a few third party apps (games, social media, news, etc) installed and they're all up to date (my co-worker has an identical phone which he got at the same time as mine and he's running almost the same apps as me and his is fine).

The phone has never been dropped or damaged, never been jail broken, only opened once three days ago to replace the battery.

Any ideas? If it were a straight battery issue I would've thought the replacement would've been fine.

I know the iPhone 6 has issues but I hadn't heard anything about the 6S.

(and FYI New Zealand doesn't have any Apple Stores so I can't really go find a genius. )

 

[Funsize93]

A few questions:
Was your battery replaced at an Authorised repairer?
Did you restore the phone as new without restoring the backup and tested without user data?

You need to isolate a software/ hardware issue.

If you restore the device using DFU mode and setting it up as new without user data and the issue persists more than likely that would indicate an underlying hardware issue. Not necessarily regarding the battery but could be another hardware component being faulty draining the battery instead. I would recommend contacting Apple support if the issue persists after performing the steps above and have them run a remote diagnostics or reserve an appointment at your nearest Apple Store.

If you find that your device does have a hardware failure and your device has no unauthorised modifications you may be entitled for a repair covered under the Consumer Law in NZ, if the device was purchased and you still reside in NZ.

 

[Candlelight]

A few questions:
Was your battery replaced at an Authorised repairer?
Did you restore the phone as new without restoring the backup and tested without user data?

You need to isolate a software/ hardware issue.

If you restore the device using DFU mode and setting it up as new without user data and the issue persists more than likely that would indicate an underlying hardware issue. Not necessarily regarding the battery but could be another hardware component being faulty draining the battery instead. I would recommend contacting Apple support if the issue persists after performing the steps above and have them run a remote diagnostics or reserve an appointment at your nearest Apple Store.

If you find that your device does have a hardware failure and your device has no unauthorised modifications you may be entitled for a repair covered under the Consumer Law in NZ, if the device was purchased and you still reside in NZ.

Thanks for the reply. The battery was a genuine apple replacement but I replaced the battery myself (I work in IT and have done this a couple of dozen of times).

I have currently wiped the phone using DFU mode and am setting it up as new with just the defaults, and will leave it off the charger overnight. If it's dead in the morning, I'll contact Apple.

 

[Candlelight]

So I left it off the charger overnight. Went from 100% at 10.30pm down to 19% at 6am.

About to contact Mr Apple.

 

[Newtons Apple]

How did you get hold of a OEM Apple battery? They do not sell them.

If they detect you have had you phone opened and worked on, they could refuse any service.

 

[JPack]

A battery drain problem like this is often due to a problem with the "Tristar" power management IC. That chip gets damaged if you charge the phone using a poor quality USB charger, such as cigarette lighters.

If you've already wiped the phone, it's clearly not a software issue.

 

[Candlelight]

A battery drain problem like this is often due to a problem with the "Tristar" power management IC. That chip gets damaged if you charge the phone using a poor quality USB charger, such as cigarette lighters.

That's interesting. I've only ever used genuine chargers and cables.