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        General >> Give/Need advice to/from others >> Cossie Alternator - on-load output voltage? 
        
(Message started by: KeithCEng on Jul 8^th, 2009, 12:07pm)

Title: Cossie Alternator - on-load output voltage?
Post by KeithCEng on Jul 8^th, 2009, 12:07pm

Hi - I hope someone can help me with the following:

Should the A1271 (100A) Alternator on the Cossie be capable of giving an output voltage of 13.9V at tickover speed (700 RPM) with all possible electrical loads in operation (Full headlights/Fogs/Heated Seats/Heated windows/Fan etc.)??

Mine only gives 11.6V under these conditions, despite being a genuine Ford exchange item, fitted last September. Even at 3000 RPM, the voltage only climbs to 12.2V with this full electrical load. With a moderate load (Headlights/Fogs/Heated Seats only) at tickover, the voltage is 13.6V, rising to 13.9V at light load.

The Battery was replaced last November.

I have also noticed that my battery goes flat if the car is left unused for a couple of weeks - Could these symptoms be related and if so, what would be the most likely cause?

Cheers

KeithCEng

Title: Re: Cossie Alternator - on-load output voltage?
Post by tlundkvi on Jul 11^th, 2009, 2:22pm

Yes, 13.7 - 14.1 V should be expected. Never seen less than 13.5 at idle (mine is a factory new Magneti Marelli fitted last October).

Have there been fluids etc. dropping onto the alternator? If so, even a new one could fail.

Title: Re: Cossie Alternator - on-load output voltage?
Post by KeithCEng on Jul 12^th, 2009, 6:21pm

Hi Tlundkvi,

Thanks for that info - no fluids have leaked onto the alternator. I am just wondering if one (or more) of the rectifier diodes on the stator has failed? Is there a procedure for checking this without removing the alternator from the car (using a suitable Multimeter)?

Cheers

Keith

Title: Re: Cossie Alternator - on-load output voltage?
Post by tlundkvi on Jul 12^th, 2009, 7:26pm

I had dim battery light, which within a month turned to full battery light.

You can monitor voltage levels while engine is on (apart from a multimeter) by doing the following:

Press trip reset until beep is heard
The LCD segments all light up
Press reset - short presses -check display until voltage shows up.

Try using the radio and check levels. Made my already bad alternator rectifiers fail, right in the middle of autobahn in Germany (when I lived there). Limped home with spark plug power taken from the battery...