Dead Battery and voltage readings assitance needed
03-01-2014, 10:08 PM
#31
Race Car
My 87 S4's voltage dropped to less than 10 out of the blue Thursday with no red warning light. Ran fine except the voltmeter registered as low as it could but will twitch when I use the turn signals. Drove home parked it.
It barely started Friday afternoon and the battery was unable to start the car late Friday night.
Put a charger on it for ten minutes or so and it started right up. Turn the car off and disconnect the charger and car won't start to the sound of the starter solenoid clicking.
Took some measurements:
Jump post at rest : 11.66 At idle: 11.57
Battery at rest: 11.68 At idle: 11.47
Cigar lighter at idle: 10.94
Battery is less than 2 years old. Bought from Advance Auto.
I think the battery is in need of replacement. I am charging the battery and will run past Advance Auto this morning.
It barely started Friday afternoon and the battery was unable to start the car late Friday night.
Put a charger on it for ten minutes or so and it started right up. Turn the car off and disconnect the charger and car won't start to the sound of the starter solenoid clicking.
Took some measurements:
Jump post at rest : 11.66 At idle: 11.57
Battery at rest: 11.68 At idle: 11.47
Cigar lighter at idle: 10.94
Battery is less than 2 years old. Bought from Advance Auto.
I think the battery is in need of replacement. I am charging the battery and will run past Advance Auto this morning.
Michael
03-02-2014, 12:04 AM
#32
Rennlist Member
On my way to Advance Auto the voltmeter started reading in its normal range 12.5 volts. The battery checked out ok and on the way home the voltmeter read less than 10. I am charging it over night.
03-02-2014, 01:37 AM
#33
Team Owner
86 from your info you should inspect the brush holder.
03-02-2014, 04:36 PM
#34
Rennlist Member
OK, I will. I brought another alternator I have from my low mileage 87 to be tested and it passed - I may do a swap.
Also, I have had the battery directly on a trickle charger for 24+ hours and the best it can muster is 62.5% charge. That does not seem right. I may need a battery, too.
-Kevin
Also, I have had the battery directly on a trickle charger for 24+ hours and the best it can muster is 62.5% charge. That does not seem right. I may need a battery, too.
-Kevin
03-08-2014, 03:13 PM
#35
Rennlist Member
I pulled the brushes and I think I see the issue. 
I have brushes from a tested alternator to swap in.
I have brushes from a tested alternator to swap in.
