Charging Issue

[Crew Man]

Cold start the voltage hovers around 14 for a few minutes then drops to about 13.2 all day. I'll get a scan done and go from there. Appreciate your knowledge on this. Cheers.

 

[krusing]

They should maintain approx. 14.1 > 14.4 [no higher] when running,
It possible may drop at some stage.
My LY7 maintains a constant charge voltage of 14.1 > 14.4 all the time,
Drops to 13.6 > 13.8 with headlights on.

As a far fetched question,
have you tried/tested another alternator ?
It seams to me to be undercharging.


Side note:
Whereas the Brushes were worn out on my alternator,
I replaced those, and the bearings, (checked the rotor contacts, as they were fine) and its been charging fine since.

 

[Crew Man]

Hi guys, 05 VZ SSV Crewman LS1. Cold start, dash voltmeter reads 12 volts at idle, checked with Voltmeter at battery 11.97 volts. If l turn it off and leave for 3 minutes, voltmeter reads 14 volts. Replaced Alternator and battery with new ones, same problem. No problem during the day with multiple stops/starts. It’s always that first start up for the day. Any ideas? Thanks in advance.

Well, the saga continues, still have had the intermittent no charge at first start, leave for 2 minutes, it usually charges. Yesterday, the Alternator stopped charging. Replaced with the genuine Mitsubishi with the same numbers. Still no charge. Auto electrician says there is no power on the 2 wire plug at the alternator. Is it part of the Instrument cluster? Do I have to unravel all the wiring from the alternator back as far as I can? Is there a possibility of a blown fuse in the fuse box under the bonnet? No faults show up on a scan. This thing is driving me mad!!!

 

[lout]

looks like crewman use the basic vz alternator
does the red battery light come on at selftest
does it go out when engine starts
if no power on white wire to alt check the brown fusible link (super size fuse under bonnet fuse box)
but would expect a lot more things not working
follow the 2 pin plug from alternator back giving a gentle pull on wires, sounds like a break somewhere
seems strange that both wires are open though

 

[Crew Man]

The red battery light comes on when ignition is turned on (not started) and goes out when started. Will have an in depth look at the harness from the alternator back. And find/check the fusible link. Thanks for your input. Cheers.

 

[Jolls]

Hi Crewman

I'm surprised that your auto sparky couldn't resolve this one for you. If it is failing to produce the correct voltage with a new alternator it is most likely because the field has not been excited. The armature relies on the field to create magnetic flux so that the armature can cut the field and produce an alternating currrent. This is then transformed to DC using a bridge rectifier (essentially a series of one way diodes) and regulated. See the description below from the manual.

Circuit Overview
With the ignition switch it the ON position and the engine at rest, current is supplied via the regulator to G8 – X2 pin 1
(circuit 225) to the power control module (PCM) at connector A84 – X2 pin 15. Refer to 2.4 Wiring Diagram. This initiates
current flow (within the regulator) from the generator G8 – X1 pin A to the brushes and rotor winding, to excite the circuit.
The current in the rotor winding creates magnetic fields between adjacent rotor poles.
With the engine running, the rotor spins, the stator windings cut through this field at right angles and induce voltage. As
the engine speed increases, this induced voltage increases. Current then flows through the three-phase diode bridge in
the rectifier to convert the AC voltage to DC. This is supplied to the G8 – X1 pin A output and then to the battery terminal
X86 – B (circuit 1).
The regulator monitors the voltage to the battery. When this voltage reaches approximately 14.5 V, the regulator opens
the circuit through the rotor winding, causing the generator output voltage to drop. When the regulator senses a voltage
below a preset value, the regulator closes the circuit through the rotor winding and voltage to the battery again increases.
This cycle repeats very rapidly.
Current does not flow through the rotor winding when the engine is cranking.

My recommendation is to download the VT-VZ Manual and go to Section 6D3-1 (the charging system). You find may a link to the manual here.

Once you have the manual there is a series of diagnostic tables to allow you to identify and rectify the charging issue.

Cheers n Beers
Jolls

 

[Crew Man]

Thanks for the reply Jolls. Will pass on the info and see where it leads. Have traced the wiring as far as I can, can't see any anomalies. Have cleaned all the Earths too.

 

[Crew Man]

Finally got to the bottom of it. The brown wire at the 2 pin plug on the alternator had a dodgy connection. Resoldered it and like new again. Anybody wanna buy a Gen III alternator or 2?? One is brand new, the other is 3 months old!!

 

[Jolls]

Finally got to the bottom of it. The brown wire at the 2 pin plug on the alternator had a dodgy connection. Resoldered it and like new again. Anybody wanna buy a Gen III alternator or 2?? One is brand new, the other is 3 months old!!

Great result - I trust that you can move the spare alternators on and get some of the cost back.

Cheers n Beers
Jolls