ScoobyForLife27

iTrader: (14)

Hi guys.
Car is running fine from start with no problems at all, voltage over 14 (turbo timer reading). Then after few minutes, whatever lights are on (dash, head lights etc) start to flickering and voltage is jumping from 14 to 11. It is going on like that for 2-3 minutes and than back to normal for another few minutes. Engine revs are steady. I could understand if that was like that all the time but it's keep changing, a few minutes normal and then bad again.*
The only thing I can think of is faulty alternator. Am I right thinking this direction ?
Thank You

JDM_Stig

iTrader: (3)

have you checked the plug and connections on the alternator, and also is the belt nice and tight.

ScoobyForLife27

iTrader: (14)

Yes I did.
Plugs are fine and belt seems to be tight.

ScoobyForLife27

iTrader: (14)

Other ideas ?

ScoobyForLife27

iTrader: (14)

Ok. Just checked the battery voltage again and it's 11.7
I'll put it in charge for whole night and see what happens.

Turbotits

iTrader: (2)

check the main earths are tight and clean

PhilWrx100

11.7 volts is very low? Suprised you can start the car with the battery that flat. Maybe a dead/dying cell.

ScoobyForLife27

iTrader: (14)

Car starts perfect with no hassle at all. Just got the battery out and waiting for my friend coming with proper voltage meter.

ScoobyForLife27

iTrader: (14)

Ok. Battery is out and voltage meter shows 12.3 but battery charger shows that battery is flat. Weird, isn't it ?
Will see after few hours.

J44CE

Sounds like a faulty voltage regulator in the alternator to me. If the battery I's nackered and the engine is running the alternator should show Atleast 14volts. If it jumps up and down I would say voltage regulator in alternator. Depending on your alternator you can swap the regulator but if its built in you will need a new alternator.

ScoobyForLife27

iTrader: (14)

Hi.
Yes, it looks like voltage regulator :-(
The battery is fully charged now, 13.3 when engine is off and over 14 when is running. Still same problem. It is written on the alternator label "built in..." so new unit is needed then.

ScoobyForLife27

iTrader: (14)

That's the one.

legb4rsk

The power in the battery is in amps.So even if it reads 12v it probably has no power(amps).


You need to test a battery under a load to get a good reading of amps.

Imagine you had 8 brand new 1.5v AA batteries.They would give you a good 12v reading but wouldn't have nearly enough power(amps ) to start a car.

ScoobyForLife27

iTrader: (14)

I was hoping for bad/faulty battery but confirmed today with my local Subaru specialist - alternator is on it's way :-(
A new unit from Euro Car parts and belt will cost me £130, so don't think if there is a point of buying another second hand one for around £50 and have no guarantee how long it is going to last.