Programmable DC power supply constant current testing

Programmable DC power supply for battery discharge tests, we will use electronic load devices. However, when the programmable DC power supply is used for constant discharge of large current, it is necessary to use the electronic load device with the corresponding input rating. Low voltage and high current programmable DC power supply, current parallel maximum up to 5wA. In this paper, we give a brief introduction to the programmable DC constant current supply.

Programmable DC power system configuration

Connect the DC stable power supply to the battery in series, and then connect the load resistor.

Then, the programmable DC power supply can be tested by setting appropriate load resistance. Here, if the load resistance value is set too low, the reverse voltage will be applied to the DC stable supply and the constant discharge will not be possible. On the contrary, if the load resistance value is set too high, the power consumption of the load resistance will increase, so it is necessary to pay attention to.

Formula for setting the load resistance value

R = Vbatt / I

Vbatt: maximum battery voltage (charging voltage), I: discharge current, R: load resistance

Load resistance consumes power

P = I2 × R [W]

When the programmable DC power supply uses 100A for constant discharge of 12V battery (charging voltage 14V),

Load resistance: R=14V/100A=140mΩ

Voltage setting of DC stable power supply: set slightly higher than the charging voltage of the battery 14V (about 15V)

Current setting of DC stable power supply: 100A

After the output of the DC stable power supply is connected, the switch is switched on and the constant current is discharged.