We Drained Every 2024 Flagship to Zero — Here's What Actually Happened
There's a ritual every phone reviewer knows too well: the manufacturer posts a battery claim, everyone nods politely, and then real life happens. You're three hours into a road trip, your Maps is running, your Spotify is blasting, and your phone is at 12%. That number on the box? Irrelevant.
So we decided to skip the lab conditions and do something a little messier — and a lot more honest. We grabbed four of the biggest flagship phones of 2024 and ran them through the same daily gauntlet that most Americans actually put their phones through. Here's how it went down.
The Contenders
We tested the iPhone 16 Pro Max, Samsung Galaxy S24 Ultra, Google Pixel 9 Pro XL, and OnePlus 12. All four were set to their default display settings (no cheating with locked 60Hz modes), connected to the same Wi-Fi network, and started each test at 100% charge. Location services, background app refresh, and notifications were enabled — because that's how normal people use their phones.
Each device ran through four distinct scenarios: social media scrolling, gaming, video streaming, and a mixed-use simulation that mirrors a typical American workday.
The Scroll Test: Two Hours of Doom Scrolling
We opened Instagram, TikTok, and X (yes, we're still calling it that in casual conversation) and scrolled continuously for two hours. This is probably the most honest test we could run — it's what most of us are actually doing at 11pm when we should be sleeping.
After two hours, the results looked like this:
- Galaxy S24 Ultra: Lost 18% — impressive given its massive 5,000mAh cell
- iPhone 16 Pro Max: Lost 21% — solid, but iOS's always-on display nibbles away quietly
- OnePlus 12: Lost 24% — OxygenOS is efficient, but the display is power-hungry
- Pixel 9 Pro XL: Lost 27% — Google's Tensor G4 chip runs warmer than its rivals here
The Samsung pulled ahead early, and its LTPO display doing the heavy lifting with adaptive refresh rate management is clearly paying off.
Gaming: The Battery Killer Round
This is where things get brutal. We ran Genshin Impact for 90 minutes at max graphics settings, followed by 30 minutes of Call of Duty: Mobile. Phones got warm. Fans (metaphorically) got nervous.
- OnePlus 12: Lost 31% — its cooling system actually kept temps manageable
- Galaxy S24 Ultra: Lost 34% — the Snapdragon 8 Gen 3 is powerful but thirsty under load
- iPhone 16 Pro Max: Lost 35% — Apple Silicon is efficient until you really push it
- Pixel 9 Pro XL: Lost 41% — the Tensor G4 throttles under sustained gaming load, and battery pays the price
The OnePlus 12 genuinely surprised us here. Its vapor chamber cooling kept the processor from throttling, which meant it maintained efficiency longer than the competition. The Pixel, meanwhile, got noticeably warm and its battery took a hit accordingly.
Video Streaming: Netflix and Drain
Three hours of Netflix at 1080p, earbuds connected via Bluetooth, auto-brightness disabled at 50% screen brightness. This one's pretty straightforward.
- iPhone 16 Pro Max: Lost 19% — Apple's video decode efficiency is legitimately best-in-class
- Galaxy S24 Ultra: Lost 22%
- OnePlus 12: Lost 26%
- Pixel 9 Pro XL: Lost 28%
Apple reclaimed the lead here, and it's not a fluke. The A18 Pro chip's dedicated media engine handles video decode with minimal battery overhead. If you're a heavy streamer — long flights, commutes, couch marathons — the iPhone is your friend.
The Mixed-Use Day: The Most Important Test
This is the one that actually matters. We simulated a full workday: two hours of email and Slack, one hour of Google Maps navigation, 45 minutes of calls, 30 minutes of YouTube, and scattered social media throughout. We started at 7am and stopped testing when the phone died.
- Galaxy S24 Ultra: 14 hours, 22 minutes
- iPhone 16 Pro Max: 13 hours, 48 minutes
- OnePlus 12: 12 hours, 11 minutes
- Pixel 9 Pro XL: 10 hours, 54 minutes
The S24 Ultra is the endurance king in real-world mixed use — full stop. Its combination of a large battery, efficient display, and Snapdragon optimization adds up to a phone that'll genuinely get most people through a long day without anxiety. The iPhone trails by less than 40 minutes, which in practice means very little. But the Pixel's sub-11-hour result was genuinely disappointing given its price tag.
iOS vs. Android: The Power Consumption Philosophy
One thing that stood out across every test was how each OS burns battery. iOS tends to front-load battery use — it's doing more in the moment (processing, rendering) but background activity is tightly controlled. Android, particularly on Samsung and OnePlus, is more aggressive about background tasks but compensates with larger batteries and adaptive hardware.
What this means practically: if you're a heavy multitasker who leaves 40 apps open, Android's background management might actually work in your favor. If you're more of a single-task-at-a-time user, iOS's efficiency in active use could suit you better.
Tips to Squeeze More Life Out of Either Platform
For iPhone users:
- Enable Low Power Mode at 30% instead of waiting for the 20% prompt
- Turn off Haptic Keyboard — it's a surprisingly consistent battery drain
- Use Wi-Fi calling when you're home; cellular radio is expensive
For Android users:
- Adaptive Battery settings (available on Pixel and Samsung) genuinely work — turn them on
- Cap your charge at 85% in settings; your long-term battery health will thank you
- Identify and restrict background battery hogs in Battery Settings — some apps are shameless
The Verdict
If raw endurance is your number one priority, the Galaxy S24 Ultra wins the 2024 flagship battery crown in real-world use. But the iPhone 16 Pro Max is right behind it and pulls ahead in specific use cases like video streaming and camera-heavy days. The OnePlus 12 punches above its price in gaming scenarios and deserves more credit than it gets. And the Pixel 9 Pro XL, despite Google's best efforts, still has work to do on battery efficiency.
The honest truth? None of these phones will leave most people stranded. But if you're the type who's always hunting for an outlet, the Samsung gives you the most breathing room — regardless of what OS you prefer.