The Apple Charging Situation — Built by Grumbles

The Charging Curve

Three phases. One that matters.

0 → 50%

Full-speed constant current. Your charger matters here. Only here.

50 → 80%

Current tapers. Better charger still helps. Less than you'd think.

80 → 100%

Trickle charge. 140W and 20W finish the same. Chemistry doesn't negotiate.

iPhones

No charger since 2020. Good for the planet. Confusing for everyone else.

Device	Max W	0→50% Stock	0→50% Optimal	Faster
iPhone 17 Pro Max (19.6 Wh)	40W	~38m	~20m	47%
iPhone 17 Pro (16.0 Wh)	40W	~31m	~20m	35%
iPhone 17 (14.0 Wh)	~27W	~28m	~20m	29%
iPhone 16 Pro Max (18.0 Wh)	30W	~30m	~26m	13%
iPhone 16 Plus (18.0 Wh)	~27W	~30m	~27m	10%
iPhone 16 (13.7 Wh)	~23W	~30m	~27m	10%
iPhone 15 Pro Max (17.3 Wh)	27W	~30m	~27m	10%
iPhone Air (12.3 Wh)	~20W	~30m	~30m	—

The Air is thermally capped — no charger helps. I checked.

iPads

Where the right charger matters most.

Device	Ships With	Max W	0→50% Stock	0→50% Optimal	Faster
iPad Pro 13" M4 (39.0 Wh)	20W	~35W	~1h 30m	~45m	50%
iPad Pro 11" M4 (31.3 Wh)	20W	~35W	~1h 15m	~37m	51%
iPad Air 13" M3 (36.6 Wh)	20W	~31W	~1h 25m	~55m	35%
iPad Air 11" M3 (28.9 Wh)	20W	~31W	~1h 10m	~45m	36%
iPad mini 7 (19.3 Wh)	20W	~20W	~45m	~45m	—

The Pro costs $1,299. Apple included a half-speed charger. I have feelings about this.

MacBooks

The Airs ship slow. The Pros ship right.

Device	Ships With	Max W	0→50% Stock	0→50% Optimal	Faster
MBP 16" (Pro/Max) (100 Wh)	140W	140W	~26m	~26m	—
MBP 14" (all configs) (72.4 Wh)	70–96W	96W	~30–35m	~30m	0–14%
Air 15" M4 (66.5 Wh)	35W	~70W	~60m	~30m	50%
Air 13" M4 (10-core) (53.8 Wh)	35W	~70W	~55m	~26m	53%
Air 13" M4 (8-core) (53.8 Wh)	30W	~70W	~55m	~26m	53%

Airs fast-charge at 70W but ship with 30–35W. The base M4 and 12-core Pro ship with 70W — below their 96W fast-charge threshold. Only the 14-core Pro and Max ship right.

Wearables

Any charger. Don't overthink it.

Apple Watch Series 10, Ultra 2 · AirPods Pro 2, 4, Max (USB-C)

All draw 3–7W. A 2012 cube and a 140W brick finish identical. Save the good ports.

Battery Health

Everyone worries about the wrong thing.

Heat

The #1 killer. At 45°C (113°F), lifespan is halved vs. 20°C (68°F). Your phone on a hot dashboard with a 5W charger? Worse than fast-charging indoors. I checked.

Time at 100%

High voltage stresses the cell. Optimized Battery Charging exists specifically to minimize this — holding at 80% overnight instead of sitting at 100% for hours.

Charge Depth

Shallow cycles (30–80%) are gentler than deep ones (0–100%). Apple already accounts for this in their specs. Don't obsess.

Charge Speed

Least important for Apple devices. The charge curve tapers so aggressively that "fast charging" only hits peak wattage for ~15 minutes, then throttles back on its own.

Ranked by actual impact. Most people worry about #4. They should worry about #1.

The 80% Question

Not a myth. Apple read the same papers I did.

If charging stops at	Battery lasts for	vs. 100%
100%	300–500 cycles	baseline
~90%	600–1,000 cycles	~2×
~80%	1,200–2,000 cycles	~4×
~70%	2,400–4,000 cycles	~8×

"This is the math behind Optimized Battery Charging. Every 10% Apple holds back roughly doubles battery lifespan."

Optimized Battery Charging

Learns your routine. If you unplug at 7 AM, it holds at 80% overnight and tops off at ~6:30 AM. Cuts time at max voltage from 8 hours to ~90 minutes.

Charge Limit (iOS 17+ / macOS Sequoia+)

Manual cap between 80–100% in 5% steps. Built for the "MacBook lives on the desk" crowd. If you keep devices 3+ years, this one's for you.

Thermal Throttling

Monitors temperature in real time. Reduces power when hot, pauses entirely if too hot. That steep wattage drop in the charge curve? That's this kicking in.

Cold Charging Block

Below 0°C (32°F), charging is blocked entirely — cold causes permanent damage. Between 0–10°C (32–50°F), charge speed is reduced automatically.

Above 80%, the battery is working its hardest — voltage spikes, chemistry gets stressed, wear accelerates. Apple knows. That's why all four of these exist. Also: USB-C means the device controls wattage, not the charger. A 140W brick on an iPhone delivers only what the iPhone asks for. You can't overfeed it. I tried.

Cycle Counts

Apple's promise. Your mileage will vary.

Device	Cycles to 80%
iPhone 15 and later	1,000
iPhone 14 and earlier	500
All modern MacBooks	1,000

A "cycle" isn't plug-in to unplug. It's 100% of capacity used cumulatively. 50% today + 50% tomorrow = one cycle.

Two phones with identical cycle counts can have very different health. The difference? Heat exposure, charge habits, and how often they sat at 100%. Cycles are the odometer. Temperature is the road.

Overnight
Charging

Apple already fixed this.

Optimized Battery Charging is on by default. Your phone holds at 80% most of the night and tops off before your alarm. The "8 hours at max voltage" thing people worry about? Doesn't happen anymore.

Batteries don't trickle-charge. At 100%, charging stops. Dips a few percent, tops back up. The concern was never overcharging — it was sustained high voltage. Apple fixed it years ago. Plug in. Go to sleep.

Anker Prime 160W 3-Port (A2687)

One charger. All of it.

USB-C1 (up to 140W)

MacBook — priority port, gets the most watts

USB-C2 (up to 140W)

iPad, second laptop, or iPhone 17 Pro

USB-C3 (up to 140W)

iPhone, Watch puck, AirPods — whatever's left

Ports Active	Split
One port	140W
Two ports	~78W + ~76W
All three	~60W + ~50W + ~35W

160W total. Splits dynamically. The display shows you exactly who's getting what.

That Little White Charger

Found one in the drawer. Did the math.

Device	0→50% That charger	0→50% 20W	0→50% Optimal
iPhone 17 Pro Max	~2h+	~38m	~20m
iPhone 17	~1h 45m	~28m	~20m
iPad Pro 13" M4	~4h+	~1h 30m	~45m
iPad Air 13" M3	~4h+	~1h 25m	~55m
MacBook Air 15" M4	won't charge	~3h+	~30m

Apple shipped this 5W charger with every iPhone from 2007 to 2019. Then stopped including chargers entirely. Hundreds of millions still in drawers. And yes — it's USB-A, so you need a USB-A to USB-C cable for anything made after 2023. Still in use. Still slow.