zhmontana

Sorry this is long, I really appreciate any advice or help you can offer...

I had never had any issues with my battery. Then in January in Tahoe I left my lights on for about 4 hours (dumb) by accident. It was dead, had to get a jump to get started, but had no further problems in the following days. Then got an engine light (unrelated) about a week later and when a friend checked it with the VAG he noticed a bunch of "short to ground" codes, besides the catalytic converter code that had actually turned the light on. He dismissed them after I told him about the dead battery in Tahoe and just reset them for me. Now fast forward to the end of Feb and I left the car at the airport for 7 days still having not had any trouble since the dead battery in Tahoe. When I returned from my trip the ar started somewhat groggily (such as low battery, but after only a week?), but started none the less. In the few days since my return I have been noticing it become more and more sluggish to start until this morning. I started ar, again sluggish, and drove it a couple miles and left it for the majority of the day (took team bus to cycling race in berkeley). Upon my return, the battery was dead. I got it jumped drove it around for 30 minutes and then had the battery tested at jiffy lube. He said it read 12V 600 CCA. I think it is supposed to be 760 CCA? I have since shutdown and restarted the car (today since it was tested) with no issues (starting right up) 3 times. Anyway, now to the question... did I ruin my battery when I killed it in Tahoe and it is finally catching up with me by not holding the charge or does it sound like I really do have shorts that are killing my battery slowly when I let it sit and don't drive many miles between starts????
Thanks in advance

Studly_1

A good automatic charger with a 2amp 'trickle charge' feature will top off the battery. I bought mine at Sears. It should take overnight, but it could go up to a day. One big discharge harms the battery, but doesn't necessarily spell doom for it. A long drive of several hours might charge it up, but it's a big strain on the alternator (I fried my Porsche alt. this way - $$$).

Keep in mind that 4-5 years is considered 'normal' battery life. You may want to go straight to replace if this is your original battery. I'd get the charger; it's handy to have anyway. What team are you on?

zhmontana

I appreciate the feedback and suppose it is possible that I just didn't get it charged back up with my regular driving over the last few days after the airport sit. It is possible that the battery is just getting old too, I bought the ar CPO with 40k and it now has 60k. But the codes thrown about shorts to ground make me nervous and don't know if they actually exist or if they were just residual from the dead battery in Tahoe. Anyway, regardless for some reason my battery went from perfectly charged sitting at the airport for 7 days to dead 3 days after I got back and don't understand why.
Oh, I race for bicycle planet. Today was the Pinole Team TT in berkeley. It was fun.

paulroad

Its 4 years... but b4 i put a new one in, I track the shorts..if you still have a warranty...just bring it in to the dealer.

zhmontana

It is hard to get to my dealer though (like 2-3 week lead time) and they are awful. They charge me for everything even with the warranty. They say things like, it will cost you $300 to put it on the scope, if something is replaced underwarranty then the warranty will pay, otherwise you pay. This even happened once with an engine light where there was something wrong, but they said they have to reset it once to see if it comes back and made me pay anyway. And there aren't really any other options here in sacramento.

zhmontana

I am going to test tomorrow with my meter to see what kind of current is being drawn when the car is off. I would like to check with the security system armed but not sure if I can do this with the hood up?

Studly_1

A battery can seem charged enough to start the car and run fine even when it's only partially charged. Remember it was fully depleted. For my rarely driven Porsche, I always use the automatic charger. There's a green light when the battery is full. The battery will start the car after it sits a few weeks, but it needs an overnight charge to be full.

Since your first dead battery was caused by lights left on, charge it fully. You may have caused shorts by jumping the car. It's likely the battery just never recovered fully. Think about it. Why would there be shorts now? If it drove well for 7 days - every drain on the gassed battery would 'look' like a short to the ECU.

squishball

I think you batt is toast. Normal engine off voltage is typically above 13v.

zhmontana

Makes sense... thanks

ar2002

It's a 12V battery; it only reads significantly higher when being charged (engine running).