The TEC-06 battery discharge test device: Manual

Foreword & Warning

First, I have to give a warning: The following text about the TEC-06 (v5.4) is the result of taking together the information which could be found on the net at the beginning of September, 2018. These text documents are horrible translations from, most probably, Chinese into something remotely similar to English. Therefore, I cannot guarantee anything of the (hopefully) facts described in this document. The use of the information herein is solely on your own risk and responsibility!

The text is still not finalized!

If you have any suggestions regarding this text, please, let me know! In this case, write to

noodle.a.mcbee [AT] tankegang.eu

Thank you!

So let’s start…

Description

The TEC-06 is a constant current electronic load. It uses a high-precision DAC loop control technique to control the output current of a power supply or a battery. The current will be kept constant, independently from changes in tension (voltage). The load resistors are onboard, there is no need for an external load separate from the board. This load is linear, there is no PWM mode.

The TEC-06 will automatically calculate the product of discharge current and time to measure the battery capacity. The TEC-06 can also be used as an electronic load to verify the battery or power output capacity.

Specifications

Maximum current: 3.5A; error <= 0.5%
Maximum power: 16W
Operating temperature: -20° through +70° Celsius

Features

  1. Encoder switch (shuttle) operation, easy and convenient.
  2. Precise current adjustment, the full range error is within 0.5%.
  3. Integrated fan, discharge power can be up to 16W and the fan will be automatically switched on or off according to the power.
  4. Supports 4-wire measurement. Only with a 4-wire connection the battery’s internal resistance can be measured.
  5. Maximum battery voltage is 15V, and cut-off voltage can be adjusted randomly in the range of 1 through 12V by steps of 0.05V.
  6. When the battery current is too low, the device will automatically adjust the resistance until the actual current meets the set value. When the actual current is lower than 40% of the preset value, the device will end discharging.
  7. Mini-USB interface (5V) for power supply, the current consumption is about 240mA.
  8. Maximum detection capacity is 500,000mAh (500Ah).

The LEDs and the display

Beneath the 4-digit display there is a vertical line of five LEDs:

  1. Ah -> The accumulated measured capacity
  2. V -> Battery voltage (momentarily measured value)
  3. V -> The set cut-off voltage (as defined by the user)
  4. mA -> Actual current (the current in the battery circuit)
  5. mΩ -> The battery’s internal resistance (can only be measured if the battery has been connected in a 4-wire mode, see diagram below)

The four-wire connection

The connection to the V- and V+ terminals should be done with very thin wires, whereas the wires ending on the I+ and I- terminals should be thick enough to stand the expected current.

I+  I-  V-  V+
|   |   |   |
|   +---+   |
|       |   |
+---+-------+
    |   |
    B+  B-

The ASCII drawing above shows the logical connections. Physically, one would solder two wires directly to each battery pole, a thick one for the connection to the I terminal, a thin one for the V terminal.

How to operate

  1. Connect the battery.
    a) With measurement of the internal resistance: Use 4-wire technique.
    b) Without measurement of the internal resistance: Use a 2-wire connection. In this case the battery must be connected to I+ and I-. Needless to say, but battery plus to I+, battery minus to I-.
  2. Turn on the power by connecting the micro-USB port to a standard USB charger.
  3. Set the cut-off voltage which applies for your type of battery. You can destroy the battery when choosing the wrong value! It can begin to burn or even explode, so carefully read the manufacturer’s instructions for use of your type of battery!
    Turn the encoder knob to the cut-off voltage position, press the switch. Cut-off voltage flashes, that means that the desired value now can be set. Turn the knob to set the desired cut-off voltage. The minimum adjustment step is 0.05V. The parameter is stored in the device to complete the cut-off voltage setting.
  4. Set the current: Turn the rotary switch to the current display mode. The setting method is the same as above. The adjustment step is 50mA within a range from 50mA through 500mA. The adjustment step is 100mA above 500mA. The maximum current is 3.5A.
    NOTABENE: The maximum power is always 16W! In accordance to P=U*I, the current will never be higher than 16W/U, wherein U is the actual off-load voltage of your battery. So, e. g., a 12V battery measurement can only be set to a current of 1300mA in theory, practically I could set it only to 1200mA in this case.
  5. Start/Stop
    Two modes are available:a) Mode 1: Turn knob to display capacity, press switch to start. To pause the process, simply press the switch again.

    b) Mode 2: Turn knob to display measured battery voltage, press switch to start.After the discharge starts the device will dissipate heat. When the discharge power is greater than 2.2W the fan will power on, if it is less than 2W the fan will stop.

  6. End of process: When the battery voltage is lower than the cut-off voltage, the device stops discharging the battery, the measurement is completed, and then the display flashes, showing the final discharge capacity. To stop flashing, press the knob.
  7. Measure again: Press the switch for 3 seconds or re-power on to do this.

Special Functions

  1. Maximum power limit function: The TEC-06 limits the maximum discharge power. When the user sets the discharge current to a value, so that the power consumption is greater than 16W, the device will automatically adjust the discharge current, so that the power stays below 16W.
  2. Battery discharge capacity detection function: When the maximum discharge current of the battery can not reach the set value, the device will automatically reduce the discharge current.
  3. Cycle display function: In the internal resistance display mode, click the switch and the device will automatically cycle through the five measurements.