A car battery helps power your car's engine and provides a charge for all electrical and electronic accessories. As the battery in your car ages, it will lose its ability to hold a charge or could be 'drained' by accident. Car batteries are drained when someone inadvertently leaves an electrical item on, such as a radio, in the vehicle without the engine running. You will need to consider size, cold cranking amps, battery "freshness" and reserve capacity as you learn how to buy a car battery.
Steps

Step 1. Know the size of the battery for the needs of your car depending on its make and model
- Consult your owner's manual. The manual usually specifies the size of the battery you should buy.
Buy a Car Battery Step 1Bullet1 - Ask an auto parts store for the correct battery size.
Buy a Car Battery Step 1Bullet2
Step 2. Select the correct battery size and type according to your driving needs
Keep HVAC and handling needs in mind and check your owner's manual for the correct size. Consider the size, which refers to the external dimensions of the battery and the placement of the terminals. If you buy a battery that is too small, it will probably not be properly installed in your car compartment.
- High temperatures are harmful to batteries. The electrolyte solution in batteries evaporates faster in hot weather.
Buy a Car Battery Step 2Bullet1 - A long battery life is important if your daily driving habits consist mainly of short trips. Short trips do not allow the battery to recharge. A long-life battery will have more resistance on those short trips.
Buy a Car Battery Step 2Bullet2

Step 3. Check that the battery has been in the store for less than 6 months
The date stamp code on the battery gives you the "freshness" of the battery. The first two characters are a letter and a digit - A means January, B February, etc.; the number specifies the year the battery was manufactured - 7 means 2007, 9 2009. The date stamp code is engraved on the battery cover. You can find it while checking the battery cover

Step 4. Ask for cold cranking amps (CCA) and cranking amps (AC)
Both are critical, especially if you live in cold climates.
- CCA refers to the ability of the battery to start the car at -17 C. CCA also indicates how much charge the battery delivers to the running of the car.
- AC refers to how much charge the battery delivers to the vehicle in temperatures of 0 C. This rating is usually higher than CCA.

Step 5. Ask about the reserve capacity of the batteries they have for sale
Reserve capacity is the ratio of how many minutes the battery can be used by itself. It's good to know the reserve capacity in case your car's alternator might fail

Step 6. Verify the difference between maintenance-free versus low-maintenance batteries
- Maintenance-free batteries do not require the addition of water.
Buy a Car Battery Step 6Bullet1 - Low maintenance batteries are unsealed and have cover caps that allow you to add water to them, which is important to consider if you live in hot climates.
Buy a Car Battery Step 6Bullet2
Advice
- Go to a workshop and ask for a charge test as soon as you realize that your battery charge is getting weak. This will tell you if the battery is holding a charge. If it is not, you will need to change it. When your car is slow to start, it could be a sign that your car's battery charge is getting weak.
- Automobile batteries must be disposed of carefully and properly due to their lead content. An auto parts store is equipped to handle lead waste. You will be charged for a "helmet", which is a disposal fee which you can apply as a discount towards the new battery.
Warnings
- Never dispose of an old battery in household waste. Remember that it contains sulfuric acid which is corrosive and also produces lead sulfate which is highly toxic.
- If it is a battery that is not sealed, you must purchase a container of distilled and demineralized water made for this purpose. Do not add tap water or drinking water, it could damage it since they are mixed with other components.