Hello, welcome to Auto Clinic Care. Today's focus is batteries. It seems like everything in Rockville runs on batteries. Of course, the batteries we're most concerned with here at Auto Clinic Care are those in our customer's vehicles. Just like the batteries in our smoke detectors or TV remote, 
they wear out and need to be replaced . This can be thought of as the power output used to start a cold vehicle engine. The number of cold cranking amps you need depends on your vehicle and where you live in MD, specifically how cold it is. (Many Rockville drivers have first-hand experience trying to start their car on a cold winter morning.) The two factors are that the colder your vehicle's engine is, the more power it takes to turn the engine over to get it started. It has all that cold, sluggish oil to contend with.
The other factor is that the chemical reaction in the battery that creates electrical energy is less efficient when the temperature dips. Let's say it's 80 degrees Fahrenheit (27 degrees C) in Rockville. At that temperature, 100% of the battery's power is available. At freezing, only 65% of battery power is available, but it requires 155% as much power to start the engine as it did at 80 degrees F (27 degrees C).
As you can see, the colder it gets, more power is needed, but the available power drops.
So if you live where it's cold in MD, you need a battery with more cold cranking amps than you do where it's moderate or hot. The battery that originally came with your vehicle was based on averages. At Auto Clinic Care, we like to remind Rockville drivers that they should always get at least as many cold cranking amps as their vehicle manufacturer recommends but may want to upgrade if they live where it gets real cold.
Auto Clinic Care
5531 Nicholson Lane
Rockville, MD 20852
301.881.7891
http://WWW.autocliniccare.com