Buying used smartphones can be a bit of a minefield, but there are some excellent bargains to be had if you know what to look for. Often, you might have to forgo the original box, or perhaps a few of the normal accessories are missing which lowers the asking price. In that latter case, you might not want to pick up that second-hand OnePlus 6T. You won’t be able to fast charge a OnePlus 6T if you don’t have an official Dash or Warp Charge plug and the cable provided in the box.
I’ve been testing a number of phones to find out how nicely they play with chargers and cables from other companies. Proprietary charging technologies are increasingly common and, as such, most smartphones charge fastest when using the charger and cables in the box. However, the OnePlus 6T and the McLaren Edition are the only phones I’ve tested so far that flat-out refuse to charge quickly if you ditch the in-box cable or charger.
This isn’t a complete surprise, as OnePlus acknowledges that you need to use the company’s Fast Charge Type-C Cable to achieve the fastest speeds. What’s more troubling is that changing out the cable doesn’t slow charging down the speeds, it stops fast charging completely. The OnePlus 6T also doesn’t support any other charging standards as a backup.
At a minimum, a phone should draw 10W to be considered fast charging.
By comparison, the Huawei Mate 20 Pro slows down when using non-Huawei cables, but still achieves fast charging speeds. Although, the Mate 20 Pro doesn’t fast charge when using other phone chargers, making it less than ideal as well.
Meanwhile, the LG V40 is slower out-of-the-box, but provides greater than 10W of power when using both the LG and Huawei charger. This is likely because the phone makes use of the more common Quick Charge standard rather than an in-house technology, which Huawei’s charger appears to support as a backup.
The bottom line is that you can’t fast charge a OnePlus 6T with any charger or cable from a different OEM. Not exactly good news for second-hand buyers or even when charging up your phone at a friend’s house or in your car.
More important is whether the OnePlus 6T supports common third-party chargers, such as those that use USB Power Delivery or Qualcomm’s Quick Charge standards. I’ve tested that too.
Disappointingly, neither the OnePlus 6T nor the OnePlus 6T McLaren Edition support Qualcomm’s Quick Charge 3.0 adapters. The phones don’t work with USB Power Delivery either. In my opinion, this a major drawback for a high-end piece of technology and makes the phone a contributor to the irritating inconsistencies with USB Type-C devices that can be confusing for consumers.
The Mate 20 Pro, LG V40, and Google Pixel 3 XL provide fast charging speeds via USB Power Delivery. The Pixel 3 XL doesn’t like Quick Charge 3.0, but the two other phones also draw fast-charging current from a Quick Charge 3.0 adapter. Having at least one other method of fast charging, preferably USB Power Delivery, ensures compatibility with third-party chargers and accessories like power packs. That’s something that we want to see from all smartphones.
Warp Charge is a particularly bad example of a proprietary standard. It doesn't support Power Delivery as a backup.
The explosion of proprietary fast charging technologies has greatly increased the speed at which our phones go from empty to full. However, proprietary tech always runs the risk of locking consumers out of third-party products and that’s exactly the situation with the OnePlus 6T. Competitors like Huawei manage to support USB PD and Quick Charge in addition to their super fast in-house charging tech. There’s no good defense for OnePlus’ more limited technology.
Of course, this isn’t a problem if you’ll always have your OnePlus Dash or Warp Charge equipment around. But if you’re looking to buy a second-hand OnePlus 6T, make sure that it comes with the default charger and cable in the box or you’ll be stuck with slow charging speeds.