Battery question - CCA vs Reserve capacity

[Roadking]

I'm pro-actively replacing the original Panasonic battery in my 2005 4Runner. After 8 years, I think it’s time, plus it’s getting chilly here at night.

I go to the auto parts store last night and they offer two batteries, 24F (750cca/130res-cap) vs. 27F (710cca/165res-cap). They tell me the 24F is what I want ($5 more) because of the extra cca and Midwest winters...is this correct? The 27F is a physically larger battery with added reserve capacity. I’m sure either one will fit. Is one better for cold climate vs. hot climate?

Any suggestions or comments?

 

[meep]

the parts tech is generally correct, though the larger RC means there's basically more "battery" in that battery. If it were me, I'd go with the one with the higher RC... seeing that the CCA is only a ~5% difference-- basically negligable. Also helps to know what the manuf required CCA is listed to be. likely, it's quite below 710.

I think AAA installed a ~500 CCA battery in my V8 tundra, and it has no problem spinning that engine at 20F (yes, we get those here in the south).

 

[PandaBear]

I'd go with what the manufacturer spec for your car. I am more worried about a larger physical size battery will be a good thing.

Also will a larger RC battery last longer? It should only mean it would stay charged longer vs a battery that will crank in the cold better (and deplete sooner).

 

[Danno]

I agree with going with higher reserve capacity. The CCA difference is minor.
I tend to stay away from high CCA batteries such as 1000 CCA as the battery plates are thin and packed closely which tends to reduce the battery life.
Another reason to go with the 27F.

 

[eljefino]

You only need as much CCA as your car requires. As said, "more" is a compromise elsewhere.

The CCA test is a somewhat artificial 30 second crank time, BTW.

With gear reduction starters, you don't need a bazillion amps like the old days. In a way I'd want the RC just because of all the parasitic loads when the car is off.

As said above, more CCA is made with thinner plates and the drop off as years go by can be steeper and even pass an initially worse battery. So you aren't necessarily buying "quality" with more CCA.

Long story short, since your shelf takes the 27F, that sounds muy bueno. They can fit more of everything in a bigger case.

 

[nitehawk55]

Reserve capacity is your friend in cold climates .

 

[HTSS_TR]

The larger 27F with more RC is my choice too. Larger battery with less CCA usually means thicker plates, thicker plates = longer life.