Analogic Sound

This repair post is for a GWM Hover 2.4i(4G64 mitsubishi engine) SMD354804 generator.

The generator is made in china, it is 90 amp rated and it has been in service for 5 years(100.000km).
The problem is that the generator could no longer charge the battery and when you switch on the aircon and the low beam, voltage drops below 12 volts. With no load connected the generator manages to keep a steady 14.1 volt.
Another sign of malfunction is that the charging symbol(battery symbol) stays on for a few good seconds after start-up, this was the main reason to check the charging system performace.

Another reason for this check is that the winter is comming soon, you don’t want to do repairs in a -10 celsius day and you want your systems up’n’ready.

An overall system check was performed, battery check, electrical wiring and all connections have been checked.This confirmed that the generator is in a bad shape and needs a rebuild.

The generator on the workbench, first step was to make a sign on it(you can use a permanent marker) for us to know the exact position of the generator parts.
You can see the exposed rotor and the bearing, a good opportunity for a nice cleaning and we also added some lithium grease to that bearing, though the bearing sounded fine and no bearing play was observed.
You can see the opened bearing seal:

First sign of trouble was already present as one of the brushes fell down from its place showing some high temp melting damage:

After all tests, we were sure that the problem was given by the brush connection melting. The generator managed to keep the charging function at a lower rate using the spring of the bush as a connection. But not for long as the heat generated by this poor connection damaged the spring, affecting the overall performance of the device.

The rotor check:

Here you can see burned brush connection:

Everything was cleaned using compressed air and gasoline.We didn’t use gasoline for the rotor in order not to wash the grease in the bearings.

A new brush kit including new springs was used from BOSCH:

Brushes soldered in the old cleaned build-in regulator:

Here is the retainer pin used to hold the brushes not to damage them in the mounting process:

Regulator resoldered with a high power soldering tool:

Few other nice pictures:

Unit ready for another 100.000km service:

Charging test were successful, at idle speed(750rpm) 14.42 with no load, 14.39 with the low beam on, 14.22 with the high beam+fog lights and a nice 13.50v with ALL load ON (all lights on, aircon on, defrost on, seat heating on):

Let the winter be here!

In the end we must say that in our opinion the damage was possible because of the frequently jump starts given with the engine ON.If you want a healthy generator, it is better for you to do the jump start of another car with the engine OFF, this saves generator from heavy loads.
The quality of parts is not the very best in these chinese units but inadequate use leaded to early malfunction of the charging system.