Micro USB V8 Cable 2016 High Quality New Arrival Nice Black White Colors USB Car Charger (WHL #15)
Today, I have something springy for you. A powerful car charger for two of your favourite electronics!
…except I broke it during first use Prepare for some Wan Hung Lo qualitty goodness!
I bought this fine piece of equipment for 2.48€ at AliExpress back in November. And I got my money back.
Notice something? Well…the center pin looks a bit…retracted. But first things first. As I have a matching car receptacle to test such things with lab equipment instead of doing measurements in the car, I first tried the charger at my lab power supply. And what do you know, it worked out of the
box bag. Voltage was fine over a large variation of input voltages, certainly exceeding everything the charger would experience in a real car.
I also set up more circuitry to test the charger under load. And, surprise, it performed well. High efficiency, current almost as advertised when using both USB ports. Both of my current phones did charge on it. When using only one, current wouldn’t compete with a 2 amp Samsung charger, but it delivered well over one ampere. More than enough to keep a phone going when using GPS navigation and what not.
As this is not the right way that Wan Hung Lo equipment should behave, I decided to actually use it in my car before review. And before taking photos of it, which is why I only have the photos from the AliExpress dispute ready. My old charger is only capable of less than one amp, which is exceeded by my new phone, causing the charger to reset and shut down after a few tries. Not very helpful.
So I plugged this one in – and it didn’t work. On both phones. The old charger still does, so the car plug is still functional. After some head scratching and basic IT problem solving (“have you tried turning it off and on again”), I noticed the problem. The friggen positive center pin is missing
Well, it is not. It’s just not at the right place anymore. The plug in my car must have pushed it out of the center, from which it disappeared and was never seen again.
When opening the two-piece shiny plastic body, which is only possible by squeezing at the end (pipe wrench FTW) so that the cover plate falls off, one can start pulling the PCB out. Press the two negative contacts and the whole thing is moving.
Adequate construction, poor soldering, dangerous production. And the missing center pin actually is a hollow cap and put onto a spring. It isn’t soldered or press-fitted, it’s just sitting on top of the stronger brother of a ball pen spring. The collar in the plastic case isn’t long enough, so when the bottom of the plug isn’t flat (like in my lab unit) but has a small protruding pin, the positive terminal is pushed into the case and will never come back. Poof goes your charger.
Some details on the electronic components: There isn’t much on the PCB as you can see, a 47µF/50V (…why) input electrolytic cap buffers the supply voltage, and a 220µF/16V cap does the same for the output. There is a bootstrap diode installed as advised in the data sheet (see below), and some tiny SMD stuff for the IC. The recommended Schottky diode for further boosting the efficiency is missing. The biggest part, the inductor, is not labelled. And there’s a blue 3mm LED installed, which, see the last picture, didn’t have the pins clipped. So this one might short-circuit when touching the output USB port casing, congratulations
The IC is labelled “CXW8509 S18417U”, but I only found a datasheet concerning the “CX8509” from a “Shenzhen Core Micro Technology” company:
The CX8509 is a monolithic synchronous buck regulator. The device integrates 100mΩ MOSFETS that provide 2A continuous load current over a wide operating input voltage of 4.75V to 25V. Current mode control provides fast transient response and cycle-by-cycle current limit.
Guess that’s the same unit, as pinout matches the PCB very well and it’s exactly doing that. So this driver is capable of much more than just supplying plain 5V from a 11-14V car battery source. The case states 2.1A at 12-24V, so they didn’t overspec that much. Still, at around 0.6Ω to 0.7Ω round-trip resistance of the flimsy leads, one would not get that much juice from the Micro USB (the mounted full-size USB is fine).
My verdict? Excellent Wan Hung Lo product. Good design, shitty implementation, breaks at first use – would not buy again.
But now I have another great 5-25V in, 5V/2A out buck converter in my parts bin. For free! Aaand I’m still missing the car charger…