Updated · Batteries
What the number means
CCA is the current, in amps, that a new, fully charged 12-volt battery can deliver for 30 seconds at 0°F while staying above 7.2 volts. Cold thickens engine oil and slows the battery's chemistry at the same moment, so a freezing start is the hardest job a battery does.
A battery rated 650 CCA passed that test at 650 amps or more. The higher the number, the more starting power it has in cold weather.
CCA, CA and reserve capacity
Battery labels often carry several numbers. Don't compare a CA number on one battery with a CCA number on another; they measure different things.
- CCA: starting power at 0°F
- CA or MCA: starting power at 32°F, so it's always a bigger number than CCA
- Reserve capacity (RC): how many minutes the battery can supply 25 amps before dropping too low, useful if the alternator quits
- Amp-hours (Ah): total stored energy, common on European-style and AGM batteries
How much CCA your car needs
The owner's manual or the label on the original battery lists the minimum CCA for your engine. Bigger engines, especially V8s and diesels, need more. Stay at or above that number; going below it is where trouble starts.
Extra CCA beyond the requirement doesn't hurt the car. The starter only draws the current it needs.
Does CCA matter in Texas?
Less than in Minnesota, but it isn't irrelevant. North Texas gets hard freezes some winters, and that's often when a battery weakened by summer heat finally gives out. A battery that barely met its rating when new may not have enough left after two hot summers.
For most drivers here, the CCA your car calls for is plenty. In this climate, the battery type the car requires, its age and how it's been treated matter more than a big number.
Testing what's left
A battery's real cranking power drops as it ages. Many testers measure it and compare it with the rating on the label, which is why a three-year-old battery can show a healthy voltage and still fail a load test.
If your car cranks slowly on a cold morning, we can jump it, or bring a replacement with the right rating and install it on the spot.