Battery - CCA - Amps, what's it mean for GA's?

[Quantum]

So I'm shopping around for a new battery. My question is. How important are the CCA and Amperage of the new battery? I realize it has to be a decent car battery of course.

But for example. What's the difference between 630CCA or 680CCA?

I had my OEM battery go a couple years ago, and replaced it with one that my brother had in his old car. The replacement battery was only 525CCA, which I didn't realize before I agreed to take it.

I didn't think much of it. I've never had any starting problems whatsoever. Even on the coldest of days here in Southern Canada! ;)

I went to Wal-Mart and they suggest the 790Amp 680CCA for my car. That's fine with me, and that's what I'm going to purchase, but my question is, does it really make that much of a difference?

Is it todo with the electrical load of the car when its running? i.e. the electronic solenoids that shift the car from 1-2?

Not a pressing question, but its just for interest sake.

Regards,

[MantaGreen97]

CCA stands for Cold Cranking Amps. These are the same as CA (Cranking Amps) except measured at 0 degrees Celsius (32F) instead of the warmer temp that regular CAs are measured at.

In either case it's a measure of a battery's ability to provide current to start the car. It is how many amps you can get to crank the car, however note these ratings are made so they are "best case" or "perfect conditions" measurements, so usually in the real world you get less, but still it is a roughly standardised measurement/test done for batteries.

Usually you want to get a replacement battery that has a CCA rating equal to or greater than the stock battery.

My best advice really, is just to get the most expensive battery you can afford for your battery size. You'll notice Wal-Mart Canada carries "Energizer" branded car batteries as well as Optimas. Best thing to do is get the Optima (they only sell Red Tops at Wal-Mart), but it will cost you about $140-$150 before tax, so might be more than you're willing to spend. In that case, I'd buy the Energizer "Advanced Power" version as that is the next best thing they sell.

They both have pretty good warranties, will both exceed the CCA of the stock battery and should both be good bets for a replacement.

Edit: Also, to address your other question, no the battery isn't as important when the car is running. At that time the alternator is providing most of the electrical demands of the car. The only time the battery is really important when the car is running is at idle and there is a high electrical load/demand (or if the alternator has failed). At idle the alternator may not provide enough current for high loads at idle so the battery takes up the slack when the alt. is not turning fast enough to provide the necessary current.