iPhone 17 Charging Too Slowly? It’s Your Cable — Not Your Phone

TL;DR: If your iPhone 17 is charging slower than expected, chances are your cable or charger isn’t compatible with Apple’s new AVS fast-charging standard. The right gear can make a huge difference.

You just unboxed the new iPhone 17, plugged in your favorite USB-C cable and charger…
But 10 minutes later, the battery’s barely moved.

You’re not imagining things — and your phone isn’t defective. Most likely, your current cable and charger aren’t fully compatible with Apple’s new high-speed charging standard, USB Power Delivery 3.2 AVS.

This guide breaks down:

• Why old accessories might be slowing you down
• What AVS means and why it matters
• Exactly what type of cable and charger you need
• How to verify if you’re charging at full speed

What Changed: iPhone 17 Introduced AVS (Adjustable Voltage Supply)

Apple’s iPhone 17 and 17 Pro are the first iPhones to support USB Power Delivery 3.2 AVS, a next-gen charging spec that allows the charger to adjust voltage more precisely.

This upgrade enables Apple to promise:

“Up to 50% charge in 20 minutes.”

But that impressive speed only works with compatible gear — and that’s where most users get tripped up.

The Problem: Most Old Cables & Chargers Don’t Support AVS

Just because a cable is USB-C, or a charger is labeled 30W, doesn’t mean it’s AVS-compatible.

Common limitations include:

⚠️ Result: Your iPhone will charge — but not at maximum speed.

Solution 1: Use an AVS-Compatible Charger (Not Just Any USB-C Brick)

To fully unlock fast charging on iPhone 17, you need a charger that supports PD 3.2 with AVS (Adjustable Voltage Supply).

✅ Examples of Compatible Chargers:

💡 Tip: Look for “PD 3.2” and “AVS” in the spec sheet — if it only says “PPS” or “PD 3.0,” it’s not enough.

Solution 2: Use a Certified USB-C Cable with eMarker (5A / 100W)

It’s not just the charger. Your cable plays a big role, too.

Many USB-C cables:

• Can only handle 3A (60W)
• Lack the internal eMarker chip required for high current delivery
• Aren’t designed for AVS communication

✅ Look for cables with:

• 5A / 100W rated
• eMarker chip support
• Labeled for PD 3.2 or AVS
• Trusted brands (Anker, Belkin, UGREEN)

📌 Bonus tip: Data speed (USB 2.0 vs 3.1) doesn’t affect charging — don’t overpay for “10Gbps” if you only need power.

Solution 3: Check If You’re Actually Charging at Full Speed

Currently, iOS doesn’t clearly show real-time charging speed — but you can verify in a few ways:

🔍 Option 1: Use a USB-C Power Meter

• Small inline device that shows watts, volts, and amps
• Recommended models: MakerHawk, YZXStudio
• Shows if you’re hitting the expected 20–30W+ range

🔍 Option 2: System Settings (future iOS update)

• iOS 18 is rumored to include more visible charging metrics
• For now, you’ll have to rely on charging time and external tools

Solution 4: Know When Fast Charging Is Intentionally Limited

Even with the right hardware, fast charging may be throttled in certain scenarios:

→ Tip: For best results, fast charge between 0–50% at room temperature with screen off.

Summary: Charging Slow? Here’s the 3-Step Fix

If your iPhone 17 isn’t charging as fast as expected:

✅ Step 1: Upgrade to an AVS-Compatible Charger

Look for PD 3.2 AVS or the Apple 40W Dynamic Charger.

✅ Step 2: Use a 5A eMarker USB-C Cable

Not all USB-C cables are created equal — 100W or “AVS-ready” ones work best.

✅ Step 3: Avoid Heat & High Battery % While Charging

Fast charging is fastest under 50% and in cool conditions.

🔗 Sources & References

• 9to5Mac: What You Need for iPhone 17 Fast Charging
• The Verge: Apple’s New AVS-Compatible Charger
• Notebookcheck: AVS Not Supported on Older Chargers
• USB-IF: USB Power Delivery 3.2 Specification