rohit13

The colds starts have become very lethargic now. Before it used to jump to life. Now it feels like it will barely turn over.

The voltage on the dash shows 13.7 when I'm cranking. Now the problem is under load and idle, i.e. A/C, the voltage dips to 13 exact. The car will also intermittently sputter almost like a small misfire while in drive with ac on. Only under load aka ac.

When I turn the ac off, the battery jumps to 13.5, 13.7. It also stays 13.7 when I have the ac on and I'm driving on the free way.
I've owned the car for 4 years and have yet to replace the battery. No idea if the PO has changed it. It's the oem audi Skoda vw battery.

Is this the sign of a weak battery drawing load from my alternator when idle? No misfires, while running, or while in park. Only in drive with ac on.

This is a 01 2.8 fwd tip.

georgeb944

Replace the battery with a new one.

SloopJohnB@mac.com

I would load test the battery before replacing it, but it is highly likely if it was put in the car in 01 that it should be replaced. Just because it's an OEM vw Skoda battery doesn't mean it is an 01 battery, however. I have replaced the battery in our 2K4.2A6 twice with OEM Audi batteries…it's probably time to do it again (5+ years) but I'm going to let it die a little harder.


Your description is somewhat confusing…no battery should show 13.7 while cranking…they all go below 13 on the dash…if the battery is dropping to 13 it sounds like your voltage regulator is unable to keep up with demands…could be worn alternator brushes. You may be able to crimp/solder new brush pigtails but mine were spot welded to the contacts so I had to replace the entire voltage regulator. If you have more than 140-150K miles on that alternator it's likely the brushes are worn to or beyond the service limit, IIRC it's 5mm.

Just Me

Mine drops way below 13 when cranking, and starts like a champ.

Something does not add up here.

G

rohit13

Let me clear up some misunderstanding. While cranking, the voltage dips way below 13. I think (IIRC) it fell all the way down. It falls to 13V only under idle IN drive with AC on. If i have it in drive with AC off, it will jump .5-.7V up. (13.5-13.7)

When I was on the freeway with ac on the battery volts were 13.7 and 13.9 with ac off. As i got off the highway (AC off) the volts fell to 13.7 from 13.9 with AC OFF.

thall6594

My car hits about 12.5 volts at idle with the AC on. Nothing seems to be effected by it, so I don't worry about it. The longer I drive with the AC on the higher the voltage slowly climbs, until it hits the normal range. Driving around with out the AC I'm at a steady 14 volts.

rohit13

You are right. With ac on voltage hits 12.5.

Anyways I had battery tested and was a bad battery. Got a new one and now the ignitions are much stronger.

Just Me

Those figures sound plausible. Charging voltage will generally be ~ 14V. Static voltage ( battery only) will generally be > 12V. Cranking voltage (depends on weather, oil, phase of moon) will be around 9-10V. Not 9-10v but others are OK? Dead battery. Regulator / alternator plays no role in starting.

G