eg_atx

Three weeks ago, right at 2 years / 25k, the battery died on my 07 2.0T (accessories worked, but wouldn't start). I called the dealer, and they explained the warranty on the battery (12 months, 12k miles), so I decided to take it elsewhere. It was late, and NTB was open and convenient, so I took it there. They replaced the "dead" battery with an Exide 48/60, and all seemed to be well.

Fast forward three weeks, and now my A3 won't start again (same as before - accessories work, but won't turn over). This time I took it to the dealer (Beasley in Austin), assuming a problem with the charging system, and while they haven't diagnosed anything yet, the service tech said that it appeared that NTB sold me the wrong battery. I double-checked the specs on the NTB Exide battery with an independent mechanic, and they appear to be fine (CCA 660A, size 48, seems to fit fine).

I have asked that they check the charging system, but I am paranoid that they're just going to come back and say that I need an new OEM battery... My question: is it possible that the battery I got isn't the right match for the A3? Or is it more likely that there is a problem independent of the battery? Anyone experience anything like this?

Thanks!

happy allroader

What you describe seems to say that you have enough capacity to run the accessories but not start. That would be the battery but then you have to figure what is killing your batteries. Or it could be a starter problem. Your owner's manual should tell you the correct size battery but just about any 12V battery with 660A capacity should be more than fine. If it isn't charging you should be getting a red light on the dash and the voltmeter would stay below 12. What you describe almost sounds like leaving the dome light on overnight. Somebody smart could probably check to see if the car is sucking electricity when it shouldn't.

Charge the battery then check the capacity. If you do a capacity check of the battery (at most shops for free) they can put a load on the battery to see if has the required capacity (give you Volts and Amps). By checking the battery you can eliminate that as a cause.

It could be a starter solenoid going bad? Bad alarm / security system? Bad starter/ignition switch? Whatever the switch that senses park/neutral for auto transmissions or the sensor for 'you got the clutch in' for manual is going bad?

Ask the tech why he says you bought the wrong battery. It isn't like Audi really makes their own batteries.

eg_atx

NTB did check the original battery and said that it was showing two bad cells. Immediately after replacing the battery, the car started fine, so I assumed the issue was the battery and not the starter/etc.

Over the last two weeks, I thought I was noticing that the car seemed to take slightly longer to start, but I just assumed I was being paranoid. This morning, on first start, the car cranked more than usual but eventually started. I was suspicious, so I shut it off and tried starting it again, and it didn't start the second time. I jumped it and took it to the dealer.

I don't have any aftermarket accessories, and I double-checked the usual suspects (dome light, etc.), and nothing appeared to be on.

It's under warranty, but I'm a bit nervous about dealer run-around before the issue is ultimately diagnosed and resolved.

dfrost

Have you cleaned the battery terminals?

The original symptoms you described sound exactly like dirty terminals, although you said that NTB found several bad cells on the original battery. Wife's Mazda6 was recently displaying some VERY odd symptoms different from yours, which was its version of a bad cell (battery still showed 12+ volts).

It would, however, be surprising to still have a dirty terminal after the battery was just replaced.

eg_atx

They looked basically new, to me anyway. no corrosion, etc.

The more I think about it, I am leaning towards the alternator. It would make sense given the symptoms, if it's producing enough power to drive the car but not charge the battery. The new battery (not being charged by alternator) probably had about 3 weeks of starts in it before it drained. That's my working theory, anyway.

We'll see what the dealer says.

Thanks,
Eric

UncleNoName

my battery died after 15 months... first time battery lasted so little