How to Replace Rechargeable 12V 3Ah Batteries
You find yourself with a full tank of gas and yet your car won't run; it's likely your battery is dead or without enough charge to actually help start the engine. Car batteries don't last forever (and sometimes only last a few years), so finding the right rechargeable 12V battery for your vehicle can help to ensure reliable use.
How do rechargeable car batteries work?
All batteries workby utilizing a chemical reaction's chemical energy to create electrical energy.
- Most car batteries have six cells that comprise the 12-volt total when fully charged. These batteries are lead acid, meaning lead and lead dioxide plates are submerged into sulfuric acid within the sealed cell, and the acid triggers the chemical reaction. This creates electrons, which turn into electrical energy.
- A running vehicle recharges a lead-acid battery. The alternator is driven by the engine, which works as the charger. Jump-starting a dead or low battery can allow it to charge once the vehicle is running.
- A rechargeable battery undergoes self-discharge, meaning it loses charge when it's not in use. This is can lead to dead batteries occurring in vehicles stored for extended periods.
How can I tell if my car battery is dead, or if it needs to be replaced?
Your vehicle not starting is one symptom of a bad battery, but this can be discovered before finding out the hard way.
- The first step is turning off the ignition and headlights and double checking for anything else that could be using power.
- A working lead-acid battery could still test poorly due to its terminals, and you can check them by holding a multimeter's red probe to the positive terminal and having an assistant crank the engine. If it reads more than 0.5 volts, cleaning the clamps or replacing the battery is in order.
- Removing the battery's positive terminal is the first step in testing the battery itself. Set the multimeter to the lowest setting above 15 volts and connect the negative lead to the negative terminal and the red lead to the positive. It should read 12.4 to 12.7 volts, and if it doesn't, it could be under- or overcharged or in need of replacement.
Which car battery do I buy?
Different vehicles and usage determine which battery is right for yours, and there are several characteristics on which to base a decision.
- The physical size, or Group Size, is important. CCA (cold cranking amps) refers to the ability to start the engine in cold temperatures. Reserve capacity (RC), amp hour, and C20 capacity refer to how long a new battery could run the car on its own and how much energy is stored. Many car batteries are 3Ah.
- Car manufacturers specify the requirements in these areas for their vehicles. Information can be found in the manual or from the manufacturer.
- Stores that sell car batteries often have a book that you can consult or an employee you can ask for help. Choosing the right rechargeable battery is very important to ensure the proper operation of the vehicle.