How to Calculate Cold Cranking Ampsby Bryan Clark
Cold Cranking Amps, or CCA, is the measure of how much current, or amperes, your battery can provide for thirty seconds when it is started at zero degrees Fahrenheit. Additionally, during this time of current supply, the battery is not allowed to drop below a certain voltage threshold. Most manufacturers consider this threshold to be below 10.5 volts. This number is calculated on every vehicle, and is especially important to vehicles that will be exposed to these kinds of conditions.
Put on your rubber work gloves. Battery acid is very harmful to your skin. Rubber is also a good insulator to prevent electrical shock.
Place your multimeter on the ground near your engine. Make sure that it is in a well-ventilated space.
Open your hood and locate your battery.
Loosen the two bolts on the positive and negative terminals of your battery using the socket set.
Place the positive and negative leads of the multimeter on the appropriate leads of the battery. If there is grime built up on the connection space, you can clean it with baking soda and water. Be sure the terminals are completely dry before you reconnect them.
Tighten the bolts on the battery terminals to ensure a proper connection.
Turn on your multimeter and select the appropriate function to read CCA. Not all multimeters have this function, although it is becoming more common on lower-priced units.
Start the car and wait 30 seconds. After 30 seconds, shut off the vehicle and check your multimeter for the CCA readings. Readings should be displayed on a graph with a peak CCA reading and an average CCA reading included.
- Battery University: Battery Overview
- "Industrial Applications of Batteries: From Cars to Aerospace and Energy Storage"; Michel Broussely and Gianfranco Pistoia; 2007
Things You'll Need
- Socket Set
- Battery multimeter with CCA reading
Bryan Clark has been a freelance writer since 2002. His work has appeared in "The New York Times," "USA Today" and the U.K.'s biggest paper—"The Guardian," amongst other, smaller publications.