Nexus 4 and Nexus 5 natively support Qi wireless charging. I have decided to get one to reduce the chance of damaging the Nexus 5 micro USB port – unlike most other people who use wireless charging, I don’t finding plugging in a cable to charge a phone to be inconvenient.
The name-brand wireless chargers are very expensive. The Google Nexus 4 wireless charging orb even got really poor reviews in Amazon. So I may as well get a cheap one – even if it does not work too well it will not be a great loss. The cheapest wireless chargers in China now start from RMB50 (about USD8.5). However, reviews of those chargers sometimes contain complaints about very slow charging, inability to position correctly for charging to work, heat, or a premature failure. So I tried to find one that at least reveals its manufacturer name and has some photos to show that its inside construction to have reasonable quality.
I settled on a unit that is made by a company called Smamao (its pronunciation means “digital cat” in Mandarin). I’m attracted to it because its advertisement says it uses a second-generation Ti chip, which I’m unable to confirm. I got this for RMB77 (~USD13) plus shipping (the manufacturer lists it as RMB58 each for an order of 1000). It also features a very slim design (5.8mm thick), although that is not important for me. More on this below.
What’s in the Box
– Wireless charger
– Micro USB cable
– Instruction manual in Chinese (which is pretty unimportant, but I noticed that it says the wireless charger should be placed 22cm away from human body, and 50cm away from magnetic disks, magnetic tapes, TV, radio, and watches.)
– A card that indicates QC passed
Actually, the important thing is what’s NOT in the box:
– No power supply
One may expect a wireless charger can be plugged into a wall AC outlet, but that’s not true here. Apparently all the cheap wireless chargers from China do not ship with a power supply. (The manual says the power supply can be purchased as an option, and the box already reserved some space for that.) The user is expected to use the power supply that came with the phone, and plug it into the micro USB port of the wireless charger. (Since there have been several low-quality power supply induced fire or explosions in China, even if it comes with a power supply I may choose not to use it.) Although this makes economical sense for both the manufacturer and the customer, it does have an impact to the performance. The specifications say it will output 1A if given a 1.5A input. However, the Nexus 5 charger gives 1.2A only, so this means the charging speed I get will not be the maximum that the charger potentially offers.
The advertisement says its dimensions (129.8 x 66 x 5.8mm) are designed to match iPhone 5. This is really misguided because iPhone does not support wireless charging at all. (They should really design it to match Nexus 5 instead, or even Samsung phones, which at least have a slot reserved for a wireless charging receiver.) The manufacturer sells a special case that can be fitted on the iPhone 5 to let it make use of the wireless charger. However, this case makes the iPhone 5 even longer, wider, and much thicker than it already is. I seriously doubt iPhone users will like this.
The wireless charger is indeed very slim:
- The top side of the wireless charger has a pattern done to the plastic so it looks okay even if not anything especially good
- The bottom side reveals the plastic to be cheap and looks like a toy
- There are dirt on the wireless charger, which is shown in the following photo if you magnify it:
Although the web specifications say it takes a 1.5A input, the label on the back of the charger says 2A:
Other than the dirt, the cheap-looking plastic, and the specifications discrepancies, I have no complaint about the build quality so far.
Using the Wireless Charger
It beeps! Upon connecting a power supply to the wireless charger, it flashes the red LED once and makes a beep sound. Upon placing the Nexus 5 on it, it makes a beep sound again! The red LED, even if flashed, is now covered by the Nexus 5. There is no way to turn off the beep sound, so some people may not like it.
Since the size of the wireless charger is not too different from Nexus 5, I can position the Nexus 5 easily for the wireless charging to work. (Same with Nexus 4, but not really tested much.) I tried different positions – if the Nexus 5 placement is off by 1cm to any side, then the charging does not work.
Nexus 5 Qi Wireless Charging Speed Test
The following test is done using a Nexus 5 with the free app Battery Log. Nexus 4 compatibility was briefly verified to be ok, but not actually went through a charging test. (There are other concerns with Nexus 4 wireless charging stability, and associated wakelocks in Jelly Bean, but these are not explored further for now.)
Charging measurements from 15% -> 100%:
- Nexus 5 1.2A AC charger: 106 minutes
- SMAMAO M-S1 Qi charger: 163 minutes
Speed = 106 / 163 = 65%. Since the specs say 75% efficiency, I consider this result to be not bad (although that efficiency figure probably means a different thing). When doing the wireless charging test, I have a Nillkin Frosted Shield between the wireless charger and the Nexus 5 – without this hard case perhaps the result can be slightly better (not sure).
Note: as explained before the use of the Nexus 5 1.2A charger to drive this wireless charger probably does not allow it to charge at the maximum speed.
Nexus 5 Qi Wireless Charging Temperature Test
There are fairly common complaints about wireless chargers producing heat, which will degrade battery life.
Subjectively the wireless charger being reviewed here is only slightly warm, nothing to be concerned with.
Objectively, here’s the figures from Battery Log:
- Nexus 5 1.2A AC charger: up to 31 degree Celsius
- SMAMAO M-S1 Qi charger: up to 38.2 degree Celsius – again since I have a hard case perhaps without it the temperature may even be slightly higher