RD USB Meter TC64



Official specifications:

• Product Model: TC64
• Display screen: 0.96 Inch color LCD display
• Voltage measurement range: 3.70 - 30.00V
• Voltage measurement resolution: 0.01V
• Current measurement range: 0 - 4.000A
• Current measurement resolution: 0.001A
• Capacity accumulation range: 0 - 99999mAh
• Voltage measurement accuracy: ±(0.8% + 4 digits under 25°C)
• Energy accumulation range: 0 - 99999mWh 999.99W
• Current measurement accuracy: ±(1% + 4 digits, under 25°C)
• Load impedance range: 1ohm- 9999.9ohm
• Power measurement range: 0 - 120W
• Temperature range: -0°C ~ 80°C / 32°F ~ 176°F
• Temperature measurement error: ±3°C / ±6°F
• Working temperature range: 0°C ~ 45°C / 32°F ~ 113°F
• Product size: 50mmx19mmx9mm
• Refresh rate: 2Hz
• Product weight: 7g (With packaging 14g)
• Quick charge recognition mode: QC2.0, QC3.0, APPLE 2.4A/2.1A/ 1A/0.5Am Android DCP, SAMSUNG

This is a USB meter with color display for USB-C, it has fast charge protocol information, but not for PD.




I got the meter in a plastic box, it did not include a manual, but a link where to download it.







The button is placed on this side.











Display and functions




The main screen with voltage, current, capacity, energy, power, temperature, bank and load equivalent resistance. The temperature is the internal temperature of the tester. There is two banks to store data in.
The icons on the right are different functions, when the button is held down a marker will slowly more down the list, release button to activate that function.
The functions are: Display off, Temperature in °C or °F, change bank, clear bank (Bank 0 is auto reset), flip display.



A fast press on the button will change between the two screens, this is the protocol screen with data line voltage and a guess about the used protocol.



Here a Quick Charge 2.0 protocol is activated and the voltage display shows 12V



Measurements

• The usb meter uses about 14mA and 7mA with display off.
• The meter will not enable a USB-C output, this must be done by the connected device.
• The meter will not show PD fast charge protocol.
• The internal resistance is about 0.1ohm (This includes both connectors).
• Usb meter will remember measured values when power is removed.
• Bank 0 will show remembered value, but automatic reset when drawing current after a power break.
• Meter only support current one way (USB-C is bidirectional).
• Voltage display is within 0.5% when no current is flowing.
• Current display is within 0.2% when voltage is within specifications.
• Software in tester is V1.4

The voltage display has good precision with no current flowing.



The current display is also precise.



M1: 56.0°C, HS1: 64.1°C



M1: 59.6°C, HS1: 68.1°C

The above IR photo was taken after 30minutes with 4A.
The readings did not change, the internal temperature readout showed 58°C



Tear down



8 small screws and it was open on both sides. To see the electronic I did only need to remove the bottom four screws.




The microprocessor is 8051 based (U4: N76E003AT20 18KB Flash, 1k RAM, 12 bit ADC), to save the data it used a EEPROM (U1: HT24LC64: 8kB 1 million write/word). The current measuring circuit is a 0.01ohm resistor and a OpAmp (U2: Marked 541IG). To power the circuit is a regulator (U0: M5333B: 3.3V). The button is also here.






The display covers this side, it is mounted with some sticky tape.









Conclusion

This is a small compact usb meter with a easy readable color display it saves Ah & Wh and show protocol information this makes it a very versatile meter with enough precision for most usages, but it is missing PD support.



Notes

For these USB meters I used precise equipment (Keithley: DMM7510, 2280S, Keysight: 34470A).
The usb meter was supplied by Rui Deng (RD) for review.

PD is the USB-C protocol for power delivery, devices made for USB-C exclusive will use this.

How do I make the test