Test/review of RD USB Meter AT35

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HKJ
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Location: Copenhagen, Denmark
Test/review of RD USB Meter AT35

RD USB Meter AT35
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Official specifications:


  • Product Model: AT35
  • Display screen: 0.96 Inch color LCD display
  • Voltage measurement range: 3.700 – 30.000V
  • Voltage measurement resolution: 0.001V
  • Current measurement range: 0 – 4.0000A
  • Current measurement resolution: 0.0001A
  • Capacity accumulation range: 0 – 99999mAh
  • Voltage measurement accuracy: ±(0.1% + 2 digits)
  • Energy accumulation range: 0 – 99999mWh 999.99W
  • Current measurement accuracy: ±(0.2% + 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
  • Product size: 64mmx22mmx12mm
  • Refresh rate: 0.5Hz
  • Quick charge recognition mode: QC2.0, QC3.0, APPLE 2.4A/2.1A/ 1A/0.5A, Android DCP, SAMSUNG

This is a USB meter with color display and fast charge protocol information.
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I got the meter in a plastic box, it did not include a manual, but a link and QR code where to download it.
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There is a single push button on the bottom of the tester.
Display and functions
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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 move 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.
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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.

Measurements

  • The usb meter uses about 16mA and 6mA with display off.
  • The internal resistance is about 0.2ohm (This includes both connectors).
  • Can only measure current in one direction.
  • 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.
  • Voltage display is within 0.005V when no current is flowing.
  • Current display is within 0.005A.
  • Software in tester is V1.7

Voltage
The voltage display has good precision with no current flowing.
Current
The current display is also precise.
Temp7081
M1: 52.2°C, HS1: 54.1°C
After 30 minutes with 4A current.
Temp7082
M1: 47.6°C, HS1: 55.9°C
Tear down
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There is no screws, I could just pull it apart.
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On this side is the button and a memory IC (HT24LC64).
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Here is a voltage regulator (M5333B) and a microprocessor (N76E003AT20: 8051 based 18KB flash, 1KB RAM)
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DSC_8188 chipss
One chip is probably a MUX (U6) and the other a ADC (U2).
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Conclusion
This is a small compact usb meter, with easy readable color display, saved Ah & Wh and protocol information. This makes it a very versatile meter with good precision.
Notes
For these USB meters I used precise equipment (Keithley: DMM7510, 2280S, Keysight: 34470A).
How do I make the test

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Noir
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Thanks for the review. I bought one during 11.11. sale, nice to know for sure that it is of good quality.

 

Small question: could it be that the Current (or perhaps the Display A) in the first and second line of the current table is off by one decimal place?

angerdan
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Thanks for the review!

HKJ
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Noir wrote:

Small question: could it be that the Current (or perhaps the Display A) in the first and second line of the current table is off by one decimal place?

That could very well by, but it is fixed now. Thanks.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

chargerlover
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Joined: 11/09/2019 - 02:45
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that is the good test device but I still love the way HKJ did his test with the noise and the curren stable check , those figures are more important than just see the moment of mA/V value.

chargerlover
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Could I know AT35 can record and show up the display of noise for the current ?