CCA va Reserve Capacity

[Gebo]

For some reason I got all focused on CCA's when looking into getting a new battery. But I noticed the CCA's were a lot lower in my Toyota/Lexus Batteries. The RC was very high in my OEM batteries.


My question is:

Should we be paying more attention to RC than CCA? If a battery has enough CCA to start my car, why do I need more? Looks like I'd rather have a greater RC.

 

[CR94]

Yes, if you're more concerned that some situation might run down the battery than you're worried whether the battery can deliver enough current to start the car when it's cold.

 

[Gebo]

I guess I never even looked the RC. All I did was try and get the battery with the biggest CCA.

 

[dogememe]

Less CCA but more RC batteries tend to last longer.

 

[Gebo]

Originally Posted by dogememe
Less CCA but more RC batteries tend to last longer.


Why is that?

 

[Linctex]

Originally Posted by Gebo
Originally Posted by dogememe
Less CCA but more RC batteries tend to last longer.

Why is that?


It has to do with the way the plates are constructed, and the number of them.

IIRC, more CCA = thinner plates that don't last as long, but more of them.

 

[Gebo]

Thanks. Makes sense.

 

[danez_yoda]

That is correct. If you look inside a deep cycle battery (low CCA but high reserve) you would see heavy plates. High CCA battey you would see thinner plates and more of them for increased surface area. The thinner plates wear faster than the deep cycles. They also don't tolerate deep discharge as well for similar reasons.

Generally that will be the tradeoff on similar sized batteries, lower CCA = more reserve. On some cheap batteries, lower CCA means less thin plates.

Cheap is cheap.

 

[Dave9]

Generally, it's about the (marketed) type of battery. Start versus start/run vs deep cycle.

A lower CCA battery of the same type, is just made to sell for a lower price due to thinner plates in it.

They are not thicker plates with less surface area in the same type of battery. Do not for one second think that you can get a cheaper battery of the same "starter" type and it will last longer due to thicker plates because the opposite is true.

Starter batteries use the same plate design/density, just less lead/material for less money in the lower CCA models.

The more direct answer to your question is no, you don't need to look at reserve capacity for a battery that is used only to start the vehicle and keep up with a properly working alternator. It would be different if this was a non-starter battery for a camper powering appliances.