Hey guys and gals,

I called around to a few places and they seem to have replacement batteries for my '02 A6. I decided to call the local stealership and the guys told me to make sure I get a 12 volt 450 amp battery. Strangely, all the other places were offering 800, 850,and 900cold cranking amps. So, do I spend the lesser amount of money on something that is rated at twice the amperage or spend the pricey amount that the stealership offers?

Is there any difference between regular amps and cold cranking amps? I askedmy all-mighty "dad" and he looked at me funny. I suppose that is a more complicated question than asking about an old Ford.

Any help is appreciated!

Cold Cranking Amps is a measure of the battery's current available at 0 degrees farenheit. I don't believe that there is a standard temperature for measuring amps, with each manufacturer freem to pick their own peak operating temperature. Stick with CCA for comparison. It gives you an apples to apples comparison. There is no problem with going with a higher CCA than the car's original battery.

I understand. My concern is whether or not the 450A on the Audi battery is CCA or not. Does Audi have a proprietary scale or rating of amps?

Also, I've been seeing a lot of people talking about Optima red/yellow tops. Are these worth it and is there any fabrication needed for my car?

Thanks again!

Optima makes a nice battery. But I don't think they make one for your car. To the best of my knowledge, Audi does not have a proprietary scale on rating amps. Is it possible that the dealer used an additional word in conjunction with the term amps. I am aware of the following battery power ratings:
[*]Amp Hours-the timea battery can deliver a certain amount of currentfor a particular discharge period.[*]Cranking amps -is the amount of current a battery can provide at 32°F.[*]Cold cranking amps -is the amount of current a battery can provide at 0°F.[*]Hot cranking amps -is the amount of current a battery can provide at 80°F.[*]Reserve capacity minutes orreserve capacity - is the time (in minutes) that abattery at 80°Fwill continuously deliver 25 amperes before its voltage drops below 10.5 volts.

Thanks again for your response Kevin.

So, ultimately I just need to match or exceed the CCA of the existing battery? (As well as size requirements)

Quality-wise, are there any recommendations for my 4.2L?

Have you looked at the Diehard International? It has 805 cold cranking amps and areserve capacity of 140 minutes. It is also very reasonably priced and comes with an eight year warranty.

I have replaced my VW's and Audis with genuine batteries everytime. The one for my daughters Passat was rated at 75 or 85 I believe. The factory batteries last a good long time, they are just rated differently however.

Have a look at this one from Pure Motorsports... http://www.purems.com/products/product.php/II=1788