Dead Battery

[pugman]

I am asking for my Dad as his 2011 Golf TDI would not start after sitting in the carport for two days. First things that were checked was:

1. Anything being left on - NO.
2. Voltage in the battery - approx 6 volts.
3. After charging the battery, checked to see if the Alt was charging - Yes, 13 volts at idle.

He drove the car to the Dealer and had them check for any and all problems but was told that there was no problems found. They have had the car for about 6mo now and we do not think that the battery should go dead this soon. Has anyone else experienced this and if so, what did you find the cause to be? Dumbfounded.

 

[ultrasparc]

13.0 volts is not necessarily charging, you should be able to see it around 13.7 - 14.0 volts when reved if you have a already charged battery.

Obviously the battery shouldnt go dead (6 volts is really dead) after 2 days, but this would either be a discharge somewhere or possibly a bad battery, not a charging issue.

 

[Ski in NC]

Need to test car for parasitic drain. Need a good ammeter and test battery drain current with car in the normal shutdown condition.

Agreed, charge volts at 13 is low. Double check that after driving around some to charge battery. Or test with engine rev'd to say 2000.

 

[Corsair]

Agree with the above. Also don't rule out an early battery failure- it happens sometimes. One other test you could do at home, focused on the battery is- get an external battery charger. Remove the + red cable from the battery (so the battery is not connected to the car). Charge the battery with the external charger for at least 12 hours, longer if possible. While charging, measure the Voltage at a couple different times and make note of it. Then remove the external charger and measure the Voltage of the free-standing battery immediately after the charger is removed. Then let the battery sit by itself for several hours. Measure the free-standing battery Voltage again after, say, 6 hours and again after, say, 12 hours. Battery Voltage should gradually fall (after charging) to somewhere around 12.5V to 12.0V. If you find the battery falling all by itself, below 12V or so, that's good indication the battery is defective.
[edit] - if you do this, also may want to have your radio code handy (usually a card in the owners manual) in case the radio asks for code after being de-powered for a significant time.

 

[oilhammer]

You need to check for drains as outlined in TSB 27-07-11.