The ASUS Zenbook 15 OLED UM3504 is a premium 15-inch laptop powered by the AMD Ryzen 7 7735U processor. It supports charging via USB-C on its Thunderbolt 4 port — a convenient feature for users who travel with a single cable. When USB-C charging stops working, it can leave you hunting for the original barrel charger or stuck near an outlet.
This guide explains why USB-C charging fails and walks you through every fix to restore it.
Why USB-C Charging Stops Working
USB-C charging on the Zenbook 15 OLED requires both hardware and software to cooperate. Common failure points include:
- Charger wattage too low — the UM3504 requires at least 65W via USB-C Power Delivery; lower wattage adapters may not charge under load
- USB-C port used instead of Thunderbolt 4 port — only the Thunderbolt 4 port on this model supports full charging speeds
- Outdated BIOS or USB-C controller firmware — older firmware versions have known Power Delivery negotiation bugs
- Windows power settings conflict — battery charge threshold settings in MyASUS can interfere
- Cable issue — not all USB-C cables support Power Delivery; a data-only cable will not charge
Step-by-Step Fixes
Fix 1: Use the Correct Port and a Certified Charger
On the ASUS Zenbook 15 OLED UM3504, USB-C charging works through the Thunderbolt 4 port. Use a USB-C charger rated at 65W or higher with Power Delivery (PD) support. GaN chargers from brands like Anker, Baseus, or UGREEN work reliably. Make sure the cable itself is a full-featured USB-C cable, not a charge-only or data-only cable.
Fix 2: Check the Battery Charge Limit in MyASUS
- Open the MyASUS app from the Start menu
- Go to Customization > Battery Care
- If a charge limit (such as 80%) is set, the laptop will not charge beyond that point and may appear to not charge at all if the battery is already above the threshold
- Temporarily set it to Full Capacity Mode to test
“My Zenbook 15 showed ‘plugged in, not charging’ via USB-C for days. It turned out MyASUS had a battery limit set to 60%. Switching to Full Capacity mode fixed it instantly.”
— Rina Mohd Nor, digital marketer
Fix 3: Update BIOS and Thunderbolt Firmware
Visit the ASUS Support page for the Zenbook 15 OLED UM3504. Download and install the latest BIOS update and Thunderbolt Controller firmware. ASUS frequently patches USB-C Power Delivery behavior in BIOS releases.
Fix 4: Reset EC (Embedded Controller)
Shut down the laptop completely and unplug all cables. Hold the power button for 30 seconds to drain residual charge and reset the embedded controller. Reconnect the USB-C charger and power on.
Fix 5: Reinstall Thunderbolt Driver
In Device Manager, expand Universal Serial Bus controllers and look for the Intel Thunderbolt 4 USB Controller. Right-click and choose Update driver. If the problem persists, uninstall the device and restart to let Windows reinstall it.
Frequently Asked Questions
Ryan holds a Computer Science degree and has spent over 15 years troubleshooting Windows hardware and driver issues across major laptop brands. He writes practical, step-by-step guides for everyday users at softwaredriverdownload.com.
What wattage USB-C charger does the ASUS Zenbook 15 OLED UM3504 need?
ASUS recommends a minimum of 65W USB-C Power Delivery for the Zenbook 15 OLED UM3504. A 45W charger may charge slowly or not at all under heavy CPU load. A 100W charger offers the fastest charging speed.
Can I charge the Zenbook 15 OLED UM3504 from any USB-C port?
Only the Thunderbolt 4 port on this model supports USB-C Power Delivery charging. The standard USB-C port may support data transfer but not power input. Check the port markings for the Thunderbolt symbol.
Why does my Zenbook 15 show plugged in, not charging?
This usually means the battery charge limit in MyASUS is set below the current charge level, or the charger wattage is insufficient. Check the MyASUS Battery Care settings and switch to Full Capacity Mode to test.
Does the Zenbook 15 OLED UM3504 support USB-C charging while in sleep mode?
Yes. As long as the charger meets the wattage requirement, the laptop charges in sleep, hibernate, and shutdown states through the Thunderbolt 4 port.
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