inverter no vac output and the error code is DCBUS-L by HeliosII


HeliosII-485MCP off grid solar inverter


inverter no vac output and the error code is DCBUS-L.

Fault Causes

1.customer connected on the output other voltage engine generstor

Solutions and steps

As illustrated in above image, the place marked by red box is the actual location of IPM module.

The four points within the red ellipse are the points we need to measure.

Measurement procedures: measure IPM module-using  multimeter, 

and discharge white capacitance at first.

1.Use black probe to connect 0 point, and use red probe to connect 1, 2, 3 point respectively. 

The value of measurement should be more than 500 normally.

 2. Change black probe and red probe connection points. 

Use red probe to connect 0 point, and connect 1, 2, 3 point 
using black probe respectively. The value should be 1 under
 normal condition as shown below, in another words,
 exceeding multimeter’s measurement range.

If check all display 0V, means AC output part Mosfet(IPM Module) damaged.


1. Send back to factory to check

2. change the Mosfet