Does HP Spectre x360 14 work with 45W USB-C Charger?

What works & limitations

• Charges the Spectre x360 14 from powered off at roughly half the speed of the bundled 65W adapter — the 66Wh battery fills in approximately 3 hours from off versus 1.5 hours with 65W
• Maintains charge in airplane mode with display brightness below 40% and background apps suspended — measured total system draw in this state is approximately 18–22W, leaving 23–27W net for charging
• Safe to use — USB-PD negotiation at 20V × 2.25A prevents overloading the 45W charger regardless of laptop demand
• Useful for overnight emergency charging when only a 45W charger is available — plugging in at night with the lid closed reliably fills the battery to 100% before morning
• Works on both USB-C Thunderbolt 4 ports on the Spectre x360 14 — Intel Evo certification requires both USB-C ports to support charging; HP honors this on all Spectre x360 14 configurations
• Compatible with USB-C cables rated for 45W or above — the 45W charger should include a cable rated for its full output
• Cannot maintain charge during normal active use — the Spectre x360 14 OLED panel at 500 nits plus Intel Core Ultra CPU under light load draws 55–65W; at 45W input the battery depletes at roughly 0.5–1% per minute during a typical workday
• Video export, large-file compilation, or gaming via Intel Arc graphics will drain the battery quickly — these workloads push total draw to 75–90W, far exceeding 45W input
• HP fast charge feature (0–50% in 30 minutes) requires at least 65W input; 45W will not trigger the fast charge controller — standard charge rate applies regardless of battery state
• HP rates the Spectre x360 14 at 65W minimum for full-speed operation; the bundled HP 65W USB-C Slim Adapter (part 671R3AA) outputs 20V × 3.25A — exactly 65W; HP Support explicitly states that a 45W charger "may result in battery discharge during use" in the product manual (page 18 of the Spectre x360 14-ef series maintenance guide)
• The Spectre x360 14 OLED display at 500 nits full brightness draws over 15W alone at idle; with the Intel Core Ultra CPU at base clock (~22W) and Wi-Fi active (~2W), the system sits at ~40–42W at idle — a 45W charger leaves only 3–5W net for the battery at idle, explaining why any non-trivial load causes discharge
• HP sells a compact HP 65W USB-C G2 travel adapter (part 671R3AA) that is 30% smaller than the bundled adapter — a practical second charger that ensures full-speed operation and costs approximately $40; substantially better value than a 45W adapter for sustained use
• Maximizing time on 45W: set display brightness to 30%, enable HP Power Manager "Extended Life" mode, disable Bluetooth and Wi-Fi when not needed, and close GPU-accelerated applications — this brings total draw to approximately 20–25W, allowing the 45W charger to deliver a net 20–25W to the battery