How to Determine Battery Capacity

Battery capacity consists of a measure of energy that your battery can store. In order to determine the battery capacity you will need to test for it. Testing for the capacity will tell you what your battery’s ability is to give a certain amount of current at a continuous rate, to a specific end voltage, for a certain amount of time.

Equation

Measuring energy for your battery can be done with an equation. The equation consists of dividing the capacity by your actual load current. This will give you the hours of life of the battery. A circuit that can draw 10 amps that is powered by a 9v rectangular battery can last for about fifty hours.

How to Test

In order to test your battery you will need to fill it completely with energy and allow it to empty out that energy. Knowing how long it takes helps determine what to expect from your battery life.

Why Test Your Battery

There are several reasons to test your battery. One of the many benefits is knowing where the battery is in its life line, when it is able to be predicted.

This also means that you will know when you will need to replace it, preventing you from being stuck with a dead battery unexpectedly. You are also going to be able to find all of the weak cells, as well as the faulty inter cell connectors. 

Testing Frequency

The best way to know how often you should test your battery is by checking the battery using internal resistance measurements. It is best to not base the frequency on time, but instead on the condition of the battery. Basing your tests solely on the time of the year will only be made on assumptions. Using internal resistance measurements will show any types of possible weaknesses in the battery.

Capacity Test Tips

Keep in mind that a capacity test is going to reduce your battery life. This is why you should only do it when it is necessary. That way it will make the loss of battery life worth it by knowing what condition your battery is in. Tests are done not for the longevity of the battery, but knowing what the longevity is going to be.

Keep in mind that the capacity test is only going to give you an idea of what is going on with your battery at the present time. It is not going to be able to tell you what to expect in the next year or so, if the battery is not properly taken care of. If you take good care of your battery and keep up with it in conjunction to the manufacturers’ recommendations, then the test will be more accurate concerning when you can expect to replace it.