The iPhone 18 Pro and Pro Max have finally addressed one of the most persistent complaints from power users: charging speed. With the new models, Apple promises that you can reach 50% battery in just around 15 minutes, a notable improvement over the previous generation. However, this leap in performance comes with a significant catch. If you simply plug your new iPhone 18 into the old 20W brick you have lying in a drawer, you will not see these speeds. To unlock the full 60W fast charging potential, your charger must support a specific, relatively new technology called AVS.
What is AVS?
AVS stands for Adjustable Voltage Supply. It is a feature introduced in the USB Power Delivery (USB PD) 3.1 specification and further refined in PD 3.2. To understand why Apple insists on AVS, it helps to compare it to its predecessor, PPS (Programmable Power Supply).
For years, PPS was the standard for fast charging in the Android ecosystem. It allowed devices to finely tune the voltage in very small steps (20mV) to reduce heat and improve efficiency. However, PPS has a fundamental flaw: it operates like a constant current source, which can lead to a “power cliff.” Under certain voltage conditions—particularly when a phone battery is nearly empty and needs a lower voltage but higher current—PPS can actually limit the power delivery, slowing down the charge just when you need it most.
AVS takes a different approach. Instead of acting as a current source, AVS operates as a constant voltage supply. It allows the charger and the device to negotiate a precise, steady voltage level that is closer to what the system actually needs. This avoids the efficiency losses and power limitations inherent in PPS. While AVS steps are slightly coarser (100mV instead of 20mV), this is actually more practical. Real-world factors like cable resistance and electrical noise often exceed 20mV anyway, making PPS’s theoretical precision difficult to achieve in practice. By using a more robust 100mV step, AVS delivers a stable, predictable power flow that is ideal for high-wattage, sustained charging.
Why Your iPhone 18 Needs an AVS Charger
The iPhone 18 Pro models require a 60W-capable USB-C power adapter that supports USB PD 3.1 or later with AVS. The specific voltage range relevant here is SPR AVS (Standard Power Range), which operates between 9V and 20V. This is the sweet spot for smartphones and tablets.
Without an AVS-compatible charger, your iPhone 18 will fall back to standard USB PD fixed-voltage profiles. While it will still charge, it won’t hit the 60W peak. Apple’s own technical specifications note that the fastest charging was tested using the Apple 40W Dynamic Power Adapter (Model A3351), which is capable of peaking at 60W thanks to its support for AVS.
This creates a somewhat confusing situation for consumers. A standard 65W laptop charger you might already own likely supports USB PD, but it may not support AVS. For instance, some older Apple 96W or 140W chargers do not necessarily include the AVS protocol required by the iPhone 18. You need to check for “USB PD 3.1” or “PD 3.2” and specifically look for “AVS” in the spec sheet.
How to Choose the Right iPhone Charger
When shopping for a charger to unlock the iPhone 18’s full speed, look for the following:
- Power Rating: At least 60W. A 45W charger may work, but it won’t deliver the full 60W peak.
- Protocol: USB PD 3.1 or USB PD 3.2. The critical keyword is AVS.
- Cable: You also need a USB-C cable rated for 60W (typically a cable with an E-Marker chip). The cable in the box is fine, but a cheap legacy cable will bottleneck the charge.
For a safe bet, Apple’s own 40W Dynamic Power Adapter is designed explicitly for this purpose. It dynamically adjusts its output to provide up to 60W when the iPhone 18 requests it, then steps down to lower voltages as the battery fills, all while maintaining the AVS constant-voltage profile. Third-party manufacturers like Belkin are also releasing compatible options.
The Bottom Line
The iPhone 18’s 60W charging is a genuine improvement, but it is not a plug-and-play upgrade for everyone. It signals Apple’s commitment to the newer AVS standard over the older PPS system, prioritizing stable, sustained power delivery over theoretical precision. If you want to experience the convenience of a 15-minute charge to 50%, you will need to invest in a modern, AVS-certified USB-C power adapter. Your old charger simply won’t cut it.