Steam Deck charges fastest with a charger and cable that both support Qualcomm Quick Charge. A proprietary fast-charging standard found on many Android phones with Qualcomm chipsets; recent versions are largely PD-compatible.
Using a charger that doesn’t support the device’s preferred fast-charging standard isn’t unsafe — it just falls back to a slower, universally-supported charging rate, typically 5W to 10W over basic USB.
If the device supports wireless charging, alignment matters: even a slight offset on the pad can cut the charging speed noticeably.
Look for a charger explicitly labeled with Qualcomm Quick Charge support, paired with a cable rated for the same wattage — a mismatched cable is the most common reason fast charging silently doesn’t kick in.