Using a multimeter is the most accurate way to test your rechargeable batteries.
A rechargeable NiCd battery produces 1.2 volts and about 800 milliamp hours (mAh) when fully charged and in good condition. Milliamp hours relate to the time you can expect your battery to last based upon the milliamp consumption of the device it powers. For example, if your battery produces 800 mAh and the device it powers consumes 400 mAh your battery will last 2 hours. However, the charging and discharging process gradually reduces the battery's ability to maintain full mAh, so after a period of time you find that the NiCd battery goes dead quickly. You can test the condition of your NiCd battery by using a multimeter.
Instructions
1. Read the label on the side of your NiCd rechargeable battery. It indicates the mAh the battery produces when new and fully charged. Make a note of the figure.
2. Charge your NiCd battery. Depending on your charger, the LED light will either change color or turn off when the battery is fully charged.
3. Remove the NiCd battery from the charger and let the battery rest and cool for about an hour. Don't put it in the device it powers. If you test your battery immediately after removing it from the charger you will get a false reading.
4. Turn on your multimeter. Select mAh on the control panel. You may need to press a button or turn a dial, depending on the type of meter you have.
5. Hold the prongs on the end of the two wires from the meter in your hands. Place the tips on the end of the prongs on the NiCd battery terminals. The red prong goes to the "+" terminal and the black prong goes to the "-" terminal.
6. Read the meter display panel. The mAh reading will be the same or very similar to the mAh on the battery label, if your battery is in good condition. The lower the reading, the worse the condition of your battery.
7. Calculate the percentage mAh your battery is producing. This gives you a better idea of the state of your battery. Divide the mAh reading from the meter by the mAh on the battery label and then multiply the result by 100 using a calculator. For example, if the meter reading is 650 mAh and the battery label is 800 mAh then divide 650 by 800 to get 0.81, then multiply by 100 to get 81. This means your battery is 81 percent charged. If the calculation results in a figure below 75 percent, you need to consider getting a replacement shortly.
Tags: your battery, NiCd battery, battery label, battery produces, device powers, fully charged, your NiCd