DC Power Supply Testing (Battery Charger FAT Test)

DC Power Supply Testing (Battery Charger FAT Testing) shall be performed after successful completion of assembly inspection at the manufacturing shop. You may also review DC power supply step by step assembly inspection and testing instruction.

DC Output Characteristic Test

The d-c output characteristic test of battery chargers shall be carried out together by providing storage batteries, resistors or combination of batteries and resistors, for test load, and shall be measured the d-c output voltage regulation correspond with the variation for a-c input voltage and d-c current at floating charge operation and at equalizing charge operation, and the measured values shall satisfy the data sheets and/or this specification.

The test shall be carried out following methods.  Battery chargers shall be tested at automatic transfer unless otherwise specified.

However, when the batteries are delivered under discharged condition, in such a case as oversea export of alkaline batteries, the battery charger have a function of initial charging of the batteries. The voltage adjustment range test shall be carried out at automatic transfer, and manual transfer.

Voltage Accuracy Test @ DC Power Supply Testing

The d-c output voltage shall be set at the rated d-c voltage or the floating charge operation, and the variation of d-c voltage related to the variation of the a-c input voltage and the d-c output current shall be measured.

Rated to the variation of the a-c input voltage

When the d-c output voltage shall be set at the rated voltage and the a-c input voltage is exchanged to lower limit, the rated value and upper limit, the variation of d-c output voltage shall be measured, in each case of the d-c output current, being 0 %, 50 % and 100 % of the rated current and the accuracy shall be within the specified limit.

Rated to the variation of the d-c output current

When the a-c input voltage shall be set to the rated value, the variation of the d-c output voltage shall be measured, in each case of the d-c output current, being 0 %, 50 % and 100 % of the rated current and the accuracy shall be within the specified limit in the DC power supply testing approved procedure.

Voltage Adjustment Range Test

When the a-c input voltage and the d-c output current shall be set at the rated value, the d-c output voltage adjustment range in the case of the set of voltage regulator being the lower limit or upper limit shall be measured, and variable range shall be not less than the specified value in DC power supply testing procedure. 

Drooping Characteristic Test

The d-c output current shall gradually be increased at the rated a-c input voltage, shall be measured the value when the d-c output voltage reaches to the nominal voltage of storage battery and shall be not greater than the specified value.

Load-voltage Compensating Device Test

The d-c load voltage shall be within +/-10 % of the rated voltage of the load.

Temperature Rise Test

Temperature rise (measured by the thermometer) of battery chargers shall not exceed the limits given in the applicable standards. The test shall be performed at the rated output, the rated a-c voltage, and the rated frequency.

Efficiency And Power Factor Test @ DC Power Supply Testing

Immediately after the temperature rise test, the a-c input power shall be measured at the a-c rated voltage, the rated frequency, and the rated d-c output, the efficiency shall be calculated by following formula, and the power factor shall be measured by power factor meter.

The efficiency and power factor shall meet the acceptance range as indicated by the manufacturer approved test procedure. This test shall be carried out at automatic transfer, usually.

However, when the batteries are delivered under discharged condition, in such a case as oversea export of alkaline batteries, the battery charger have a function of initial charging of the batteries, the efficiency and power factor tests shall be carried out at both transfer of automatic and manual.

Insulation Resistance Test

The insulation resistance of the following circuit shall be measured by 500 V insulation resistance tester (or as specified), before and after the high-voltage test, the each resistance values shall be 3 M Ohm and above.  In the case of an earthed circuit, it is the value when the earthing connection is removed.

  1. Between the a-c live part and cubicle
  2. Between the d-c live part and cubicle
  3. Between the a-c live part and the d-c live part

Power-Frequency Voltage Withstand Test

The 50 Hz test voltage shall be applied for 1 minute (or as specified) to the parts as shown in the following table, and no electrical and mechanical defects shall be found.

The semiconductors, electrolytic condensers, and electronic control devices are removed, before the test.  In the case of an earthed circuit, it is the value when the earthing connection is removed.

Noise Test

Sound pressure level shall be measured at four positions, 1 meter from the panel surface, using an A-weighting network. The result shall be verified as per approved DC power supply testing procedure, but normally noise level of battery chargers up to 300 A rated DC shall not exceed 85 dB(A) with A-weighted overall sound pressure level when measured at a distance of 1 meter from the cubicle at the rated operating condition.  

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