RD USB Meter AT35

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Official specifications:
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
Voltage

The voltage display has good precision with no current flowing.

Current

The current display is also precise.

Temp7081

M1: 52.2C, HS1: 54.1C
After 30 minutes with 4A current.

Temp7082

M1: 47.6C, HS1: 55.9C



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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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