Inspection and Repair

Please refer to the appropriate electric schematic diagram in SYSTEM WIRING DIAGRAMS for complete external wiring of DC/DC converter.

The DC/DC converter has to be repaired if the voltage value of the auxiliary battery is less than 12.5V when the main battery pack is fully charged or when the vehicle is running.

Symptom: Battery value less than 12.5V

Possible Causes	Corrective & Preventive Measure
30A fuse is shorted	Inspect for short circuit and replace 30A fuse after repairing the circuit.
Relay I damaged Coil is blown Contact plates damaged The "G end" Of DC/DC converter wire is disconnected (see Wiring Diagram )	Inspect and replace relay I. Inspect the resistance value of coil with multi-meter. Inspect contact plates for irregularities Inspect whether DC/DC converter G end is sending current to auxiliary battery. If not, DC/DC converter may need to be replaced.
Relay II is damaged Coil is blown at contact plates	Inspect and replace relay II. Inspect the resistance of the coil with a multimeter Inspect contacts for welds and irregularities.
Auxiliary battery is damaged	Inspect the voltage of auxiliary battery with multimeter by turning on and off DC/DC converter. If there is an a significant change, the auxiliary battery is damaged.
Failure of auxiliary battery charging circuit	Inspect whether the voltage of P1 and N1 input ends of DC/DC converter are close to 72VDC, and the voltage of P2 and N2 output ends are more than 12.5V. If there is no input current, inspect the input wire and replace relay. If there is input current but no output charge, replace output relay and/or DC/DC converter.

Symptom: Failure indicator light of charging generator is on.

Possible Causes	Corrective & Preventive Measures
Overheating safeguard. When the temperature of the shell of charger exceeds 100C, charger shuts off until temp is reduced to about 80oC.	Corrective & preventive measures Clear away contaminants on the surface of charger. Ensure good ventilation and low heat in charging environment.
The charger has shot off automatically to protect against short-circuits.	Inspect the charging circuit for any short circuits.
High and low-voltage protection. When the deviation of input power grid voltage from the rated nominal value exceeds 20%, the charger protectively turns off.	Inspect the input power grid voltage. If the regular deviation of the power grid voltage exceeds 20% of the rated nominal value, stabilize voltage.
Excess charge time protection. When the charging time exceeds 18h, the charger turns off.	Inspect the voltage and current value at the end (floating charge) of charging.
Charger is damaged.	Eliminate all the automated shutdown features described above to determine that the charger is damaged. If so, replace the charger.

WARNING: Do not wash the charger with water.