iPhone 17 Pro Max battery draining quickly

Can you define “quickly”?

If you follow the best practice of charging overnight, every night, with Optimized Charging enabled the iPhone should not need charging until the next night unless you are a very heavy user of high energy demand apps (interactive video games, heavy camera use, for example).

Here’s more information from Apple Support: If the battery in your iPhone drains too quickly - Apple Support

Gaurav_41 wrote:

The battery dropped by 6% during a 20-minute voice call. I also play games, and the battery drains by about 4% in 10 minutes of gaming.

 Prior to this device, I was using an iPhone 14 Plus, which consistently provided around 1.5 days of battery backup under similar usage conditions. However, my new iPhone 17 Pro Max is only providing approximately 20 hours of battery life,

I purchased a new iPhone 17 Pro Max approximately 6 days ago

• The iPhone 17 Pro Max reportedly has a battery capacity that is approximately 700–800 mAh larger than the iPhone 14 Plus.

• Apple advertises the iPhone 17 Pro Max as offering improved battery life compared to previous generations.

A phone call can chew through a battery fast, especially if the phone has to work harder to connect with your carrier. And you bought a phone, which has Apple Intelligence and is capable of doing a lot more than your previous phone, all of which uses power and that means the battery is working harder. A 6% drop for a 20 minute call doesn't seem out of line to me.

When you suggest you had a day and a half of charge on your previous phone suggests that you weren't following charging best practices, which is to plug your phone in to charge when you go to bed at night, with Optimized Battery Charging turned on and leave it on the charger ALL night, EVERY night. That's what just about every senior member of this forum does. We wake a phone fully charged, ready for a full days use, then plug it in to charge when we go to bed.

Don't try to babysit your battery. Just enjoy your phone or you'll drive yourself crazy.

This is a great user tip from Lawrence Finch --> When to charge your iPhone or iPad - Apple Community

The only expectation of battery usage that Apple targets to balance performance to usage is All Day Battery Life. That means you should be charging your phone all night, every night, and use Optimized Charging so it will charge to only 80% until it has learned when you normally take it off the charger.

Newer phones are faster, consume more battery, and include a larger battery to account for the increased performance in order to maintain the All Day Battery Life target. Yours providing 20 hours of usage in a day for those tasks is performing quite well.

raida777 wrote:

Battery draining quickly also heats up during call and normal daily tasks I am facing this issue too

Of course it heats during a call. Every one of the 6 billion-odd cell phones from any manufacturer used around the world heat up when making calls, because it takes huge amount of energy to operate a radio transmitter, which is only about 30% efficient. So it needs 3 times the energy from the battery to provide that 30% to the cellular radio. It’s called the Second Law of Thermodynamics. Anything that creates or uses energy does so with some loss. That lost energy becomes heat. Grade school science at work.

Battery draining quickly also heats up during call and normal daily tasks I am facing this issue too

So, the answers above would also apply to you.