Gadget
Laptop chargers are bought on wattage and trusted to just work. Most of the time they do. But when you’re paying £60 for a 65 W USB-C GaN brick that only delivers 47 W under load, something has gone wrong — and the label won’t tell you.
We spent three weeks running nine chargers — four GaN, three traditional silicon, and two no-brand units — through a fixed test protocol: 48-hour charge cycles, sustained load at 80% rated output, and infrared temperature scans every 30 minutes. All UK plugs were checked against BS 1363 pin tolerances. Here’s what we found.
What GaN actually changes
Gallium nitride semiconductors switch at higher frequencies than silicon, which means less energy lost as heat and a physically smaller transformer. A 65 W GaN charger is typically 40% smaller than its silicon equivalent — useful if you travel with a laptop and a phone charger fighting for the same bag pocket.
The efficiency advantage is real but modest at partial load: we measured 88–91% efficiency on GaN units versus 82–85% on silicon at 50% load. At full sustained load the gap narrows because GaN units that run hot throttle their output to protect the chip — a behaviour none of the marketing sheets mention.
Test results: rated vs. measured output
| Charger | Rated Output | Measured (30 min load) | Peak Temp (°C) | BS 1363 Pass |
|---|---|---|---|---|
| Lenovo 65W USB-C (OEM) | 65 W | 63.4 W | 44 | Yes |
| Anker 65W GaN Prime | 65 W | 61.8 W | 48 | Yes |
| Baseus 67W GaN | 67 W | 58.2 W | 56 | Yes |
| No-brand “65W” (market) | 65 W | 41.1 W | 71 | No |
| RavPower 61W PD | 61 W | 59.3 W | 47 | Yes |
| Apple 67W USB-C | 67 W | 65.9 W | 43 | Yes |
| Belkin 65W GaN | 65 W | 62.1 W | 45 | Yes |
| Aukey Omnia 65W | 65 W | 57.6 W | 52 | Yes |
| No-brand “45W” (market) | 45 W | 28.9 W | 74 | No |
The two no-brand units ran hot enough to trigger thermal throttling within 18 minutes and neither carried a valid UKCA marking. At 71°C surface temperature in a 22°C room, the “65W” unit exceeded safe handling limits.
USB-C Power Delivery: profiles matter
USB-C PD isn’t a single standard — it’s a negotiation. A charger advertised as 65 W might only offer a 20 V × 3 A profile. If your laptop requests 20 V × 3.25 A (65 W), the charger steps down to the next available profile — often 45 W — and you’ll see slower charging without any error message.
We used a USB-C power meter (Fnirsi FNB58) to log all negotiated profiles during testing. The Anker GaN Prime and Belkin GaN both offered full 65 W profiles to our test laptop. Baseus throttled to 45 W within 20 minutes under sustained load.
Performance ratings
What to check before you buy
The UKCA mark (or CE mark for units manufactured before January 2023) is the minimum bar for electrical safety in the UK. Beyond that, look for:
- Explicit USB-C PD profile list (not just “supports PD”)
- Over-temperature and over-current protection stated in spec sheet
- UL or TUV certification mark alongside UKCA
- A supplied cable rated to match the charger’s maximum current
Wireless charging: Qi2 vs. MagSafe vs. basic Qi
Qi2 pads now commonly ship with 15 W profiles and improved coil alignment via the Magnetic Power Profile. In our testing, a Qi2 pad charged a compatible Android phone to 50% in 38 minutes versus 54 minutes on a standard 10 W Qi pad. MagSafe on an iPhone 15 Pro reached the same 50% mark in 33 minutes — still faster, but the gap has narrowed considerably since Qi2’s launch.
Basic Qi pads (5 W default, 7.5–10 W extended) remain the cheapest option but generate noticeably more heat at the coil interface. One test unit hit 38°C on the phone’s back surface — still within safe operating range, but warmer than wired charging at equivalent speed.
Our verdict
For most users: the Anker 65W GaN Prime or Belkin 65W GaN are the safest choices in the mid-market. Both maintained their rated output, stayed cool, and carry all required UK certifications. Avoid unlabelled chargers entirely — the cost saving versus a failed laptop or a fire hazard is not rational. The Apple 67W unit leads on thermal performance but costs significantly more than the Anker equivalent for the same functional result.
If you need a travel charger that handles both laptop and phone from a single port, the Anker 65W GaN Prime’s dual-output mode reduces the laptop port to 45 W when a phone is attached — enough to maintain charge on most modern ultrabooks under light load.