Xiaomi 45W USB-C power adapter review: I still can't believe this thing only costs S$20

The power story of USB-C

USB-C is fast becoming the go-to connector system for mobile and computing devices. Apple’s MacBook Pros use it, Google’s Pixel phones use it, Samsung’s Galaxy S8 and S8+ use it, LG’s UltraFine monitors use it, SanDisk’s flash drives use it, Nintendo’s Switch gaming console use it - well, you get the idea.

The can’t-go-wrong reversible connector aside, USB-C is also quickly becoming synonymous with fast charging. That’s because with compatible devices, USB Type-C charging allows up to a 3A current for 5V devices; and on USB-C devices that additionally support the Power Delivery standard, up to 100W of power can move between the device and charger.

To cut the long story short, if everything goes according to USB-IF’s plan (that’s the non-profit organization behind the USB standard), in the future all our devices would only have USB-C ports, we’d only have one type of cable to deal with (USB-C-to-C), and as long as it can supply enough watts, the same USB-C charger/hub/power bank would work across different brands of USB-C smartphones, laptops, etc.

Enter the Xiaomi 45W USB-C power adapter

Which brings me to today’s main event: the new Xiaomi 45W USB-C power adapter. Those familiar with Xiaomi’s products will know that this is not the Chinese company’s first USB-C power adapter: the 12.5-inch and 13.3-inch Mi Book Air laptops, which support USB-C charging, already come with their own 45W and 65W USB-C adapter respectively. But this 45W adapter I’ve here (model number: CDQ02ZM) is an entirely new product that just went on sale in China as a standalone accessory. It’s made by ZMI, which for what it’s worth, is the same company that makes the popular Xiaomi-branded Mi Power Banks.

Like the Mi Book Air laptops’ adapters, this new 45W adapter uses China’s 2-pin plug (but foldable this time) and supports 100 to 240V AC and 50/60Hz frequencies, making it great for overseas use.

More importantly, this 45W adapter seems to be the first USB-C adapter that Xiaomi explicitly claims to support the USB Power Delivery v2.0 standard. The markings on the adapter seem to check out, as it advertises 5V (3A), 9V (3A), 15V (3A), and 20V (2.25A) power rules. Even the optional 12V (3A) power rule is supported by this adapter.

Additionally, the adapter also claims to support Qualcomm’s Quick Charge 3.0 standard. This is welcomed because let’s face it, most people are likely to own more Quick Charge phones than USB-C phones with Power Delivery capability at the moment.

Xiaomi is known for making value-for-money gadgets, and this 45W USB-C adapter isn’t going to break that reputation. In China, the adapter costs 99 RMB, which is about S$20. (Note: Since this adaptor isn't available here, I had to use a shipping forwarder. Even with that and local postage factored in, my total cost only came up to be around S$26.) There's a local retailer who's selling it at Lazmall now. In comparison, Apple’s 29W USB-C adapter for the 12-inch MacBook costs S$68, and Innergie’s 45W PowerGear USB-C adapter costs S$63.

A few words on performance

So, is this Xiaomi 45W USB-C power adapter any good? Short answer: it does what it says on the tin.

Longer story: here’s a summary of my findings and observations:

• The adapter uses Taiwan-based Weltrend Semiconductor’s WT6632F, a USB Power Delivery controller chipset that has just recently passed USB-IF’s certification test for USB Type-C Downstream Facing Port (DFP) applications. Depending on how and when it’s being implemented by the device maker, it technically can support USB PD 3.0/2.0, QC3.0/2.0, BC 1.2, and FCP (Fast Charge Protocol).
• Based on my testings, it’s clear the adapter supports USB PD 2.0 and QC3.0/2.0. I especially like that it supports five USB PD power rules, because that increases its compatibility with different types of USB PD devices.
• The Xiaomi adapter was able to supply roughly 42W of power to the 15-inch MacBook Pro with Touch Bar. Of course, Apple’s own 87W adapter, which is capable of 20V at 4.35A, is able to charge the laptop faster than Xiaomi’s adapter, but the point is, if you don’t mind waiting a bit (roughly 30% longer for a zero-to-full charge) or if you tend to leave your MacBook Pro to charge overnight, Xiaomi’s 45W adapter is more than serviceable. And by extension, this adapter should charge the smaller and less power-demanding MacBook at full speed.
• Expectedly, the adapter doesn’t support Huawei’s new Super Charge scheme, which means no 4.5V at 5A or 5V at 4.5A charging. But on the P10, it did manage 9V at 2A. But Huawei’s devices can be tricky: for some reason, on the P9 Plus, I couldn’t coax anything more than 5V/1A.
• This adapter isn’t really designed with iOS devices in mind, too. Be it iPhones or iPads, I couldn't get pass 5V/1A. (This suggests it doesn't support Apple's 2.1/2.4A charging schemes.) The only exception is the 12.9-inch iPad Pro, which managed to get 28W from the Xiaomi adapter, because this is the only iPad that supports USB PD. (Rumor has it that the next iPhone would support PD, so...)
• Additional notes (added Dec 21): Now that the iPhone 8 / 8 Plus and X are out, it's time to see if the Xiaomi charger plays nice with these phones. And no surprise, they do. With the iPhone 8 / 8 Plus, the 9V power rule was engaged, and the phones were charged at up to 15W. I didn't have a low-batt X with me at the time, so I didn't measure the maximum draw for that phone - but I don't expect it to vastly differ from the 8 / 8 Plus. The thing to note here is that Apple's implementation of PD at the moment is to get you to a 50% charge quickly, so don't expect the fast charge to last the whole 0 - 100% cycle. For e.g., on the iPhone 8, the draw dropped to around 9W (while maintaining 9V) when the phone got to around 20-ish percent charge. The voltage will eventually dip to 5V, and the current will also gradually drop as the phone approaches full charge.

Long story short, yes, I’d recommend the Xiaomi 45W USB-C power adapter. It is small, light, and its support for both USB Power Delivery and Quick Charge is highly sensible at this period of transition. Remember, while I mostly tested it on USB-C laptops or phones, it’s also great for charging USD PD and QC-compatible power banks.

Just take my S$20, Xiaomi.

• Update, Dec 21: Added iPhone 8, 8 Plus, and X charging observations.
• Update, Apr 18: Edited article to include how much I spent in total, after taking into account shipping cost. Article was originally published on April 15, 2017.