Car Battery Draining: A How to Guide

January 27, 2012

Having your car battery draining overnight can be a real headache for everyone. If this happens once in a while, you can recharge your car battery. But a persistent problem requires investigation. This is where you need to carry out a step-by-step check up of your car. Find out what is causing the problem and correct it, or you could land up paying hefty garage charges for a simple mistake. Follow this guide to troubleshooting your car batteries to find out what is causing the problem

Step 1- Aging Batteries

AS the battery ages, it will lose its ability to hold a charge. If the battery is new or reasonably new you can jump start the engine or you can charge the battery with a battery charger. After the car starts, you should check the alternator of the charging system of the car. If the alternator is not working, you will have to replace it with a new or a rebuilt unit. Test the unit again to make sure that the system works

Step 2- Check the Headlights and other switches

Check the car for any systems that have been left on for a prolonged period of time. Some devices continue to drain power even while the car is turned off. Check the clocks, the headlights, plugged in devices and navigation systems to make sure that they are switched off when the car is turned off. If you have multiple devices that are attached to the car, you should make sure they are all off when you have turned off the car. You can identify the systems that are causing a battery drain by using a test light. Switch off the car and then pop open the hood. Disable the hood illumination light. Then disconnect the negative battery on the terminal. Attach the test light to the negative end of the battery and wait 15 minutes. The test light should illuminate dimly. If the test light is on brightly, then there is a short circuit that is drawing on the system. You can locate the draw by removing fuses one at a time.

Step 3- Check for Short Circuits

You should also check to see that there are no short circuits. Check the wiring in the car to ensure. A short circuit can create direct loops that pull electricity from the battery, draining it completely. The speed that the battery drains is directly comparable to the size of the crossed wires. This is because a higher gauge can drain the battery faster. If the process happens repeatedly you will notice blown fuses even after using a brand new battery.

Step 4- Inactivity

Car makers inform all car owners that they have to make sure the car is used regularly to keep the battery in a working condition. Inactivity can drain the battery, but most manufacturers make sure an alternator is provided that combats the battery drainage.


Please be very careful when you check the electrical system of your car. Do not attempt it when you are not sure how to do the process.

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