Hi ,

I am a new member so bare with me. I have a 01 S60 T5 and my battery slowly died while the car was it was running until it stalled. I could hit the throttle while it was running and it wouldn't do a thing. I checked the connections to the battery and everything checked out. I suspect this means I have a bad alternator. I was wondering if there is anything I should check first before replacing the alternator?

Thanks

 

if you have a volt meter you can do some simple tests. 1) car off, measure voltage across the battery terminals. Should be in the 12.5 to 12.6V range. 2) car running at idle, measure voltage across battery terminals. should be 14V or so. Move to a fast idle - does the voltage go up beyond 15-16 or stay at 14 or so? 3) car running at idle - turn on all things electric - high beams, rear defrost, heater blower on high etc. measure across the battery - does it stay above 13V?

So analysis is if your battery is below 12V its bad. If you see over 15 or 16 volts with the car running, your voltage regulator is allowing an over charge. If car is running and can't produce more than 13 volts under load your alternator may be bad.

Now the last test - are any of the major cables to the battery getting hot (ie blubbled insulation)? that's a sign of a bad connection which may be creating resistance and lowering the ability to charge.

I suspect that if you jump start the car - you can run off the battery but the car's electronics will not like lower voltage including the electronic throttle mechanism.

 

The alternator clutch pulley on my V40 caused exactly those symptoms which in the process, damaged the alternator unit itself.
Had to replace both and no worries ever since.
Apparently if the clutch pulley is seizing/failing it cannot 'freewheel' properly which overloads the alternator. Sometimes the serpentine belt starts slipping and squealing loudly.
Mine was quiet and gave no audible warning at all.

 

UPDATE

So I was able to jumpstart the car and the car idled fine and charged the battery up just fine. I was able to shut the car off and start it under its own power. Then I turned on some electronics and it slowly died again.

I drove it around for an Hour today car ran great got back and let it idle for like 15min while i checked the voltages and the car end up doing the same slow death. This time I don't think i had any electronics on just the door open for 5 min.

The Voltages might not be accurate because the car died but..

11.4V OFF

11.15V at Idle

didn't even get to turn on the electronics but it went down to 10.5V with the lights on.


THANKS AGAIN

 

Voltage should not never be below about 13.2V with engine running with the electric's on but ideally above 14.0V. (as state above)
Mine is usually about 14.2 - 14.5.
The voltage from the battery should be about 12.5V or a little more without the engine running.
it would seem that you may have a dead cell in the battery?
I'd get the battery tested, otherwise it is likely the regulator on the alternator.

 

time for a new battery... But, that may not be the end of it as a failed alternator can kill a battery as well so best to replace the battery and retest.