5 steps to check if your car is overcharging the battery

Premium car batteries, in the best of conditions, can typically last four to five years with lower end models lasting three or less. You may find that your battery has died early and may not know why. Usually the short life is due to one of two things. First is overcharging and second is excessive heat. Heat is especially a killer near the end of the batteries normal life.

Heat you cannot do much about, but you can limit it. Excessive temperatures in the summer are the number one killer of batteries in automobiles. The best defense against this is to limit your driving during the hottest of summer hours. Also, keeping your car garaged or shaded during the summer months if possible may help some as well.

Overcharging from your vehicle's electrical system however can be taken care of fairly easily by a trained mechanic. Typically this condition is caused by excessive voltage from the charging circuit called a voltage regulator. In modern vehicles this circuit is built into the alternator, a device that supplies the vehicle it's electrical charge while running. A qualified automotive technician will be able to test for this and also and replace the alternator and or regulator should this be the cause.

Most automotive parts stores can perform this check for free, too. Alternately you can check for overcharging by using a basic voltage meter. As voltage and multi-meters have come down in price over the years you can purchase one cheaply from automotive and discount stores and do it yourself. One that has a digital read out (numbers as opposed to a gauge) is the easiest to read.

If you choose to do it yourself the following is a short set of steps to follow. Make sure to keep your hands and anything loose away from the fan and belts as the engine must be running to perform this.

NOTE: This procedure is for a car using a traditional 12 volt battery. Hybrid and all electric vehicles MUST be taken to a trained professional auto mechanic for evaluation and repair.

1. Set the meter to DC volts (it may have a symbol with one solid line on top of a dashed line)

2. Make sure the red lead (wire) is plugged into the positive (+) port (hole) and the black in the negative (-). On some models of meters the wires may already be attached.

3. With the engine running, touch the red lead to the positive post (metal part) of the battery. It will be marked with a + sign on the battery. On most cars you can tell the positive side by the red wire attached to the post. On some vehicles, however, both wires to the battery may be black and you will have to look for the positive sign (+) on the battery.

4. As you are touching the positive lead to the battery touch the black lead to the negative (-) metal post.

5. Look at the read out on your meter while holding both leads to the battery posts. If it reads much more than 14.8 volts your car may be malfunctioning and therefore killing the battery. If you find this to be the case then have a trained auto mechanic verify this as well and determine if you need a new alternator and or voltage regulator.

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