Buy from 4$ on Aliexpress Gearbest
Usb tester or so called charger doctor allows to measure the power bank’s capacity,analyze the charging process of smartphones and other gadgets, measure the necessary amount of energy needed to fully charge and consider Quick Charge operation.
The tester can measure the following parameters:
Voltage 3.60V — 32.5V with resolution 0.01V;
Current 0.01A — 5.00A with resolution 0.01A;
Power 0 — 299.999W with resolution 0.001W;
Cumulative Power 0 — 999999 Wh with resolution 0.001Wh;
Capacity 0 — 999999 mAh,with resolution 1 mah;
Charging time 0 — 999:59:59 with resolution 1 sec;
Load impedance 0 — 999 ом with resolution 1 Ohm;
Data wires voltage 0.000V — 2.999V with resolution 0.001V;
Temperature 0 — 80 ℃;
The LCD screen, 23×12.5 mm in size, has three modes of displaying information, switched by a button.
The voltage and current are displayed in large numbers in the first mode, the power, energy and time are shown in small numbers.
The time is counted as long as the load power exceeds 0.5 W (5V voltage equals to 100 mA current). Energy (Wh), charge (mAh) and time values are retained in the memory even after the tester is turned off.
The voltage and current are displayed in large numbers in the top line of the second mode, the power and the temperature are shown in small numbers, the charge (mAh), energy (Wh) and time- inside the tester.
In the third mode, the voltages on the pins of the USB input connector are displayed on the left, the load resistance, power, time, current and temperature are displayed on the right.
The tester has a screen backlight setting – it lights for 10 seconds by default. When the backlight goes out, it is hard to see the screen, but the tester consumes a record low current – 1.55 mA (the backlight consumption is also very low – 2.9 mA).
The backlight time is adjustable from 1 to 59 seconds, besides, the backlight can be permanently turned off or on .
The manganin ultra-low resistance shunt is used (according to the manufacturer- 0.05 ohms) to measure the current in the tester. The USB connectors use copper contacts. With a millimeter, I measured the resistance of the total tester along with a shunt. It was 0.133 ohms
The accuracy of voltage and current measurements was verified using a reference voltage source Keithley 2000 Multimeter precision device.Everything is perfect at a 5V voltage.
The error of current measurement is about 2%: the device shows 0.51A at a current of 0.51908A – plus/minus 1.8%-measurement error.
• high current shunt with ultra low resistance;
• ultra low power consumption (2.9 mA – with backlight, 1.55 mA without backlight);
• wide range of measured voltages (3.6-32.5 V);
• measurement of currents up to 5 A;
• energy measurement (Wh);
• memorization of energy (Wh), charge (mAh) and time;
• automatic stoppage of time calculation at load power less than 0.5 W;
• controlled screen backlight;
• voltage measurement at data contacts;
• measurement of load resistance.
• very small screen. All data, except measurements of voltage and current, are shown in small print;
• the tester is powered by the voltage of the measured source, therefore it is impossible to test the capacity of low-voltage batteries and rechargeable ones;
• flux is not washed from the contacts of connectors.
You can buy this tester from the links below: