Alternator repair

[boat193]

Hi All.
I have had my Volvo AD41 Alternator repaired, its charging ok now but the volt mtr now goes to minus 10 when I run the engine, everything else is ok Taco Ing light all work ok, I checked the charge from the Alternator its charging around 13,5v I have double checked the wires, its not possible to get them on wrong as the connections have different size holes, the Alternator is a Paris Rhone.
Any help would be great

 

[moresparks]

Hi - just to bump this up as hopefully someone with more knowledge than me can assist!
Apart from the usual tracing dodgy earth problems it is certainly a strange fault.
Just to throw in a curved ball though... is this a twin engine set-up? Do you have the emergency battery starting circuit where a push button on the dash changes the batteries over?
I remember when I was upgrading the batteries, switches, cables and solenoids etc; I was getting some very odd readings as the previous owner wired one of the relays to the wrong side of the battery on / off switch.

 

[boat193]

Hi All
I have checked with the repair shop, and all the did was a clean and function test, I have been checking things this morning, so far the Alternator is charging ok, it charges the Domestic batteries, on the wiring side of the Alternator it seams that one of the wires well its two together on one crimp connector, if I leave this disconnected all is ok Oil, Water gages ok rev counter Ing light ok, charging but the volt mtr stays at 12v.

 

[rafiki_]

I had the control unit pop on Rafiki a couple of years ago. I stupidly started the engine with shorepower connected. A good auto repaired fixed it. May be a total red herring to you, so apologies if so.

 

[simonfraser]

I had the control unit pop on Rafiki a couple of years ago. I stupidly started the engine with shorepower connected. A good auto repaired fixed it. May be a total red herring to you, so apologies if so.

why would that cause an prob ?
assuming the shore power fed the wired in mains battery charger ?

 

[rafiki_]

The shorepower caused a spike with fried the controller. Shouldn’t happen, but can do on shorepower, so good practice is to disconnect before starting up.

 

[Spare Thyme]

A shot in the dark, but if the voltmeter reads OK With the engine not running and goes minus when it is running, possible you have connected a wire that should go on the B+ to the Indicator connection. Some alternators have a diode trio that makes the alt light light. Basically the light connects to positive, the other side to the diode trio, when the alternator isn’t running it forms the negative so the light lights, when the alternator runs it produces positive so the light with 2 positives goes out. Check you connections again