Portable Powerbank Power Bank USB 1x 18650 Battery Charger Case Box for Mobile Phone MP3 (WHL #1)
It’s been a while and I was busy buying some gear…and getting some mail Now I have a decent camera ready (for almost 4 hours at the time of writing! ) and this is gonna be the first shot on Wan Hung Lo products. My light box is not ready yet, it still lacks light – box is complete , so you’ll notice my lighting and camera setup still needs some improvement. Well, that’ll come with time.
So, I had five single-cell powerbanks ready that I bought from AliExpress. Cost per unit with free shipping was 1,01€ (bulk I guess), current price is 1,05€ single or 0,98€ for bulk orders of 5+ units. It’s available in six colors: Frog green, pink, yellow, white, baby blue and black, I asked the seller to ship five green units and he did.
Features as advertised:
Brand new and high quality
Smaller, lighter, portable
Fashion style, simple and fashionable design with colorful shell
Strong compatibility for ipod, iphone, ipad, mobile, MP3, MP4, gameboy, PDA, GPS, etc
Input: DC 5V
Output: DC 5V,1000mA(Max)
Battery: Suitable for 1x 18650 3.7V Li-ion battery(not included)
Size: 9.7cm x 2.5cm x 2.2cm – 3.82inch x 0.98inch x 0.86inch
Like with all qualitty Wan Hung Lo brand goods, these are bold claims, yet the devices obviously surpass these high expectations easily.
They are brand new, I expected that. High quality…let’s talk about this later. It is in fact quite light, measuring 14 grams for the outer shell, 4g for the lid and 4g for the electronic parts, totalling 22 grams – my 18650 test cell is actually double that. Sizes given in the description are correct. By the way, the paper shown in the images has 1″ squares – I’d like to get 10mm or 5mm squares in the future (any idea where to get A3 paper or larger?). The housing does NOT fit protected cells – there’s room for that in principle, but the (+) pole would need some modifications. I haven’t tried that. Compatibility is of course dependent on the cable you’re using, so nil points for that list item. The green shell looks quite nice to me, but the white lid does spoil this a bit. It gets scratched easily, even by attacking it with your finger nails. This kills the nice matte finish in a matter of seconds. Anyways, the lid is where i started testing, see the galleries for chronological order.
It is quite hard to remove the lid in the first place. I have two other power bank designs for comparison, and those allow easy access to the batteries, making it even possible to exchange them on a regular basis in case you do not trust the charging electronics. This power bank however is a little evil with 6 plastic hooks. You have to use a guitar pick, spatula or other pry tools to release them, start at end with no USB ports on it. I actually killed my good old pick after opening all five units (and one of them twice), but that thing was already quite worn out. I have some new prying tools already shipping, so this power bank might be a nice victim for testing…
Anyways, construction-wise this thing is very simplistic. It has some U-shaped (+) pole on the PCB, and another spring loaded (-) contact that is connected by the rest of the spring metal throughout the device. Both contacts are hand-soldered to the PCB, while the rest looks reflowed. The hand solder flux residue has not been removed, look at the huge blob at the (-) terminal. Solder quality is okay, one of the caps is slightly tilted, two component footprints are not populated. Silk screen is nice, board material quality is decent. On the back, there is only a cap, a resistor and two status LEDs. They do shine through the case – I think that is a very good idea, I do not like the overly bright LEDs that you look directly into. The glowing case effect is very pleasant, see the last pictures with very little lighting and no flashlight on the camera. Blue is for discharging (starts blinking below 3.4V which is good), Red is for charging. Well, my test unit didn’t charge the 4.14V battery, but it lit up red. I guess it will do that during “proper” charging as well. I didn’t trust it enough to charge an empty one…
The chip used is a MP3401 (thanks for not scratching it off…) with date code 1529A2. I haven’t found a data sheet for it, but there is a MP34xx series from Monolithic Power Systems (MPS) that does have some 14 family members of boost converters. But maybe this one just claims to be part of this family, MPS does not list a MP3401 device. And maybe they would be ashamed of the performance, assuming the given values are not way above actual IC specs…
Whats the actual performance of this thing? To measure that, I hooked it up to my small bench supply, a good old Statron 3207 that has undergone some heavy modification on its knobs. Still, it is only a 1 amp supply, so even at perfect efficiency, I am limited to 4.2V @ 1.0A in -> 5.0V @ 0,84A out.
First test: Output voltage vs. input voltage. I ramped down from 4.2V in 0.2V steps, monitoring the output voltage with no load attached. As you can see, it sits nicely at 5.01v to 5.06V, and you can even see the charge pump adding some electrons every now and then, as it oscillates between these two voltages in a regular manner. You can spot it with your multimeter, no need to turn on the oscilloscope. So that’s fine. It also turns off or doesn’t start up below 3.3V to 3.4V, which protects your battery from over-discharge. If it’s on, it’s on and delivers the five volts – no power down circuitry, which I think is great (as I had problems with that on a device before), but obviously that draws more power than devices that do have a sleep mode.
If I add some 0.5A load from my homebrew electronic load, this changes dramatically. 0.5 amps is actually the limit – draw more and you’ll drop below 4.75V which is the lower limit of the USB spec. The voltage also drops slightly with lesser voltage input. So let’s call 0.5A the theoretical limit for this device until it gets out of spec.
Side note: Below 3.4V the blue LED flashes, indicating low battery voltage. I couldn’t test that under load conditions, as consumption went above one amp. But that’s also interesting for estimating the efficiency: 3.6V at 1.0A (partially pulsed load! baaaad!) is 3.6W in, 4.75V at 0.5A is 2.4W out – geez, 67% efficiency. At 4.2V, that’s no better – 4.2V*0.88A = 3.7W in, 4.81V*0.5A = 2.4W out – again, 65%. Not impressive unless you also want a hand warmer.
I popped in a real 18650 battery, one of my better ones, fully charged. It lasts for more than 15 minutes at 5A load (3V cutoff), so this battery will likely do anything the powerbank wants. During testing, it never went below 3.9V, but of course this is not a constant voltage supply as before. I turned the knobs slightly towards one amp, testing two of the devices. Results are shown below – round about the 0.5A mark, the voltage drops below specs. None of my five devices were able to deliver the 1000mA advertised. They did however get quite hot, too hot to touch permanently. Yet, if you consider 1/3 of the power is converted to heat, that is more than one watt to dissipate with a small SO package (the inductor didn’t get warm, not driving the tiny thing into saturation). You can also see the spread between devices, but I’m too lazy to do this with all of my units over the full range.
Last thing to note: I killed one of the devices by hooking it up to 5V supply voltage. Well, that’s no good for a
cheapo qualitty step-up converter, but I thought the chip might survive it. This actually happened without load – I did the same to all others with some load on, and they made it. But I will not repeat without load, just in case
So, what’s my verdict? I think it’s an excellent Wan Hung Lo product!
* Dirt cheap
* Hard to open without marks
* Delivering just 50% of advertised power (or going out of spec)
* Badly inefficient
* Using only the bare minimum of components, no safety rubbish
Things to improve:
* Case is actually sturdy
* Plastic doesn’t smell
* Status LEDs aren’t annoying, no sound effects
* Magic smoke escaped only one out of five times
* Doesn’t allow for over-discharge
For lower power projects (0.3A / 1.5W, seldom use) at home, this product should do the trick. Stay away if you need juice on the go, this thing wastes one third of the power you carry around.
So far, so good. Next product has already arrived, and it has a competitor from a German retail store!