Recently, there was a discount for such charging.
Now I will sort it out.
The box is simple, cardboard, fashionable eco-friendly cardboard.
There is a bag, inside here it is - charging.
Nothing says about the second function - a voltmeter.
But he is. About him later. For now, let's check how it performs its main function - it makes 5 volts out of 12.
Two ports, two usb tester, everywhere a little more than five volts. Works.
Far tester shows 1.13A, near - 1.01A. In total, it turns out 2.14A, while the voltage is kept normal.
Complicate the test:
A light bulb remained in the far one as a load, and a low-resistance resistor was switched on in the middle. 1.13A + 2.15A = 3.28A. This is close to the limit of the device, but it shows no signs of overload.
And now overload:
2.53A + 1.03A = 3.56A. But the tension fell! 4.16-4.22 volts. It turns out that the device reduces the voltage so that the current remains the maximum allowed - 3.6 A (round 3.56 to 3.6). As stated in the product description, in fact. This is the best strategy. Cheaper charges go into a cyclic reboot or even worse - they work until they die, which the user learns from smoke and flame. In one test I fed two incandescent bulbs through a different charge. The cold thread has low resistance, so it could not start the charging normally - it rebooted. After a minute or two of this twitching thread still a little heated up and the lights finally lit up. With this charge would just be a smooth start.
Charging does not heat up during operation. Let's see the efficiency:
At the input: 12.05 * 0.54 = 6.507 watts.
The output: 5.09 * 1.13 = 5.7517W.
Efficiency 5,7517 / 6,507 = 0,884
This is a good indicator.
Increase the load again:
At the input: 12.05 * 1.05 = 12.6525 watts.
At the output: 5.10 * 2.16 = 11.016W.
Efficiency 11,016 / 12,6525 = 0,87
Increase the load again:
At the input: 12.05 * 1.65 = 19.8825 watts.
The output: 5.09 * 3.30 = 16,797W.
Efficiency 16.797 / 19.8825 = 0.845
Everything is good.
And overload mode:
At the input: 12.05 * 1.5 = 18.075 watts.
The output: 4.14 * 3.6 = 14.904W.
Efficiency 14.904 / 18.075 = 0.825
Efficiency dropped a little, well, so this is an overload mode, the phone will not be charged with such voltage, the current will fall.
While all is well, can the pulsations spoil the picture? We look:
Idling. No pulsations.
The amplitude of the order of 50 mV at a frequency of 135 kHz. We can say that there are no pulsations, they are so weak.
Load 2 A. Amplitude 68 mV, at the same frequency. Such pulsations will not harm any equipment.
Three amps 86 mV. All ripple test passed.
Now the second function: a voltmeter. Glowing indicator hidden behind a dark glass front panel. Immediately attracts attention that he is not blue! He is not blue, hurray! They still ran out of blue LEDs!
We look at the compliance of voltages. As a reference voltmeter, I took an inexpensive, but very accurate instrument, a verification of which I did in a recent test of this tester located on another site. It was shown that the tester does not lie right up to the third decimal point, so now it is my most accurate voltmeter. So:
Well, charging is mistaken for one ten, understating measurements on the whole range of possible values. Not so bad for such an optional feature.
And finally - the meat!
Here's what else pleased me: the charge is relatively easy to disassemble:
First, hook the knife to the screen with a dark bladeglass It is removed, without breaking the petals, which pleasantly surprises. Then we remove the cylinder. Finally, we pull in the side contacts and with a pair of tweezers for the socket we get a board. It's simple.
The heart of the device is the CX8832 chip. She gives us the current. I searched the documentation for this chip, but found it only in Chinese. To bring it in its entirety does not make sense, but the pinout, the typical inclusion scheme and the table of characteristics are in principle clear and so.
On the reverse side of the board is a coil and two electrolytic cells. They are Low ESR, with a good voltage margin and very compact for their capacity. On the components here is clearly not saved.
On the other hand:
At the entrance there is a smd fuse. If suddenly something goes wrong, then it can be re-soldered, especially since the device is easily disassembled. This is a plus. Microcircuit on the board where the sockets are located, without marking. It must be a mikruha voltmeter.
Well that's all. Putting it back. I will take this device tomorrow to the car, now it will live there.