Car batteries will stay charged by harnessing the extra power of the car's engine and most can function for at least five years without needing to be replaced or recharged. But even the best car batteries will run out of power eventually-or lose their charge prematurely when you leave your lights on for too long. This can be a huge inconvenience. Fortunately, your car battery can be recharged without too much effort.
Step
Method 1 of 3: Preparation for Charging
Step 1. Determine what type of battery you have
This will determine the type of charger you will use. You can usually find the type written on the battery, but you may want to check the manufacturer's website. Also find out about the battery voltage by looking at the battery or in your vehicle owner's manual. Types of batteries include:
- Maintenance Free Battery
- Wet Battery (charged)
- AGM battery (absorbed glass mat)
- Gel battery
- VRLA (valve regulated lead acid) battery
Step 2. Get a car battery charger
Choose a charger that fits the battery and its purpose. Most chargers will work for all types of batteries except Gel batteries. There are fast chargers as well as "small flow" chargers that charge slowly but last longer. Use newer digital chargers, which use a microprocessor, to monitor how much the battery is charged and stop the process automatically when the battery is fully charged. Older and simpler chargers must be manually stopped to prevent dangerous overcharging.
Read the charger user manual to ensure that you are using the unit you have correctly
Step 3. If needed, remove the battery from your vehicle
Often you will be able to charge the battery without having to remove it. If you are not sure, turn off all accessories in your car and always disconnect the ground terminal first.
Step 4. Clean the battery terminals
Use baking soda and a damp cloth or sandpaper to remove any dirt or rust. You'll be cleaning so thoroughly that nothing gets in the way of the cord clamps.
Do not touch the terminal directly, especially if there is a white powder attached. This powder is usually dry sulfuric acid and can burn the skin if you touch it
Step 5. Properly position the battery charger
Place the charger on the bottom, as far away from the battery as the cord allows. Never place the charger and battery on top of each other. You should work in a well-ventilated area.
Step 6. If needed, add distilled water to each of your battery cells
Only do this if the manufacturer's instructions require it and follow the directions carefully.
Step 7. Remove the battery cell caps
Some types of batteries have a cap, at the top of the battery or below the yellow line, which must be removed to allow the gas that builds up during charging to escape.
Method 2 of 3: Battery Charging
Step 1. Plug the charger into a power outlet
Make sure it is a properly grounded outlet or you risk a fire due to electrical problems.
Step 2. Place the clamps into the appropriate battery terminal holder
The positive clamp is usually red and attaches to the positive holder with a plus sign (+). The other clamp is usually black and attaches to the negative holder with a minus sign (-). Make sure the clamps do not touch each other or with any loose metal on the battery or in the surrounding area.
Step 3. Turn on the charger and set the voltage to the amount you need
Check your battery or vehicle's instructions to find out what the appropriate voltage is. Start charging.
Step 4. Watch the battery for a few minutes to make sure nothing bad happens
Watch for sparks or smoke, or liquid leaks. If everything appears to be in good shape, it should be charging properly.
Step 5. Leave the battery long enough to charge, maybe overnight
Some chargers can do this in much less time, but to ensure a stable and long-lasting charge, use a low-flow charger and let it sit for a while.
Step 6. Go back and check the load
If your charger shows that the battery is 100% charged or reads less than one ampere, then charging is complete.
Step 7. First unplug the charger from the electrical outlet, then remove the clamp
Install the cover and return the battery to your vehicle if needed.
Method 3 of 3: Fishing Your Car Battery in an Emergency
Step 1. Read more about how to lure your car battery using another vehicle
If your battery dies and you can't find a charger, you can use another vehicle to give your car a boost so that it starts up again.
Warning
- Battery contains acid. Do not split it or leave it in the sun.
- Avoid touching metallic conductors without some kind of non-conductive protection on your hands.
- Make sure the clamp is connected to the correct polarity: red to positive (+), black to negative (-).
