Hi all! Hopefully someone can point me in the right direction. 
 

I have Fabia Monte Carlo 1.6 tdi, battery died fitted a new one with the new one being drained also.

 

Battery light comes on when I turn ignition on and goes off when the car is started. No warning light to say battery isn’t being charged or there’s a fault.

 

checked the  blue load  wire but presuming because I have an operational battery light it’s not that but tested anyway. 
 

Similar battery voltage on the red and brown and nothing on the blue until the car is running then I have the same voltage as the battery.

 

battery tested when not running was 12ishv  and when running on idle 12.8v and no effect if the car is reved. 
 

dodgy alternator?  Any help

is appreciated.

Hi Fraser, welcome to the forum. It sounds as if your alternator output may be low, not familiar with Fabia but assume it doesn't have engine idle stop - is that correct? If so, new battery shouldn't have needed coding-in to system, but it may pay to check this is the case.

 Is the auxiliary drive belt ok? (i.e. not slipping)  

How many miles has the car done?  

 

 

Thanks you for the welcome . Belts not slipping and no engine idle stop.

 

Just over 62k on it

Hmm, seems very young mileage-wise to have worn out anything in the alternator.  

Can you double-check whether you see voltage on the L terminal (pin 1, rounded side) of the alternator loom connector when ignition is switched on?  Things may have changed by 2011, but I'd expect to see that on earlier cars.

Most cars when running put out around 13.5v to keep battery topped up and when battery reaches this voltage alternator adjusts voltage not to charge any more,  the voltage you have shown is ok but should be around 13v when running so could be a fault with the alternator circuit  have you at any point before changing the battery loaned your car to some one to jump  start another car or have you done this yourself as most people CANNOT  do this job correctly and land up damaging the charging system, this also presents its self with the battery going flat as circuit is faulty and drainging battery, the only other thing is there some thing running after car is locked? boot light etc 

2 hours ago, Wino said:

Hmm, seems very young mileage-wise to have worn out anything in the alternator.  

Can you double-check whether you see voltage on the L terminal (pin 1, rounded side) of the alternator loom connector when ignition is switched on?  Things may have changed by 2011, but I'd expect to see that on earlier cars.

Is that the plug that goes onto the alternator? If so yes similar voltage to the battery. 

 

1 hour ago, Murdockman said:

Most cars when running put out around 13.5v to keep battery topped up and when battery reaches this voltage alternator adjusts voltage not to charge any more,  the voltage you have shown is ok but should be around 13v when running so could be a fault with the alternator circuit  have you at any point before changing the battery loaned your car to some one to jump  start another car or have you done this yourself as most people CANNOT  do this job correctly and land up damaging the charging system, this also presents its self with the battery going flat as circuit is faulty and drainging battery, the only other thing is there some thing running after car is locked? boot light etc 

Not jumped it or jumped from it but can’t say it’s not happened before I bought it 😃