Test the voltage and milliamp hour from your Li-ion battery using a multimeter.
Lithium-ion (Li-ion) batteries are rechargeable and are increasingly being used in many electrical appliances, replacing their forerunner, the nickel-based battery. The reason is simple: Li-ion batteries produce a nominal voltage of 3.7 volts compared to 1.2 volts from a nickel-based battery. Additionally, the milliamp hour (mAh) that can be drawn from a Li-ion battery is approximately three times the amount that can be drawn from a nickel-based battery. A Li-ion 18650 battery is the same size as a regular AA alkaline battery and generally has a nominal rating of 2,000 mAh. If you want to check that your Li-ion battery is in good condition, test it for voltage and the milliamp hour using a multimeter.
Instructions
1. Check the label on the side of the Li-ion 18650 battery to confirm its output. The voltage should read 3.7, but the milliamp hour may be greater or smaller than 2,000 (some are 3,000 mAh).
2. Find the terminal polarities of the Li-ion 18650 battery. The circular raised button on the top of the battery is the positive terminal and the flat plate on the base is the negative terminal.
3. Check the output voltage using the multimeter. Ensure that it is set to measure volts. Put the small metal rod on the end of the red cable from the meter onto the positive terminal of the Li-ion 18650 battery. Put the metal rod on the end of the black wire from the multimeter onto the negative terminal of the battery.
4. Look at the multimeter display panel. It should read between 3.6 and 3.7 volts if it's in good condition. If the battery has just been charged, the reading may be up to 4 volts, but this does decrease to 3.7 quite quickly. If the reading is below 3.5 volts, charge your battery until it is full. Let it rest for a few hours and then test the voltage again. If it remains below 3.5 volts you need to consider getting a replacement because this indicates it is losing its charge.
5. Check the milliamp hour using the multimeter. Set it to measure the milliamp hour and put the two metal rods from the multimeter onto the positive and negative battery terminals as before.
6. Check the multimeter display. A fully charged Li-ion 18650 battery in good condition measures the same as the milliamp hour printed on the battery label. Milliamp hour measurements drop as the battery discharges energy during use, so if the reading is more than 5 percent below the milliamp hour on the label put your battery on charge until full. Test the battery again. If the milliamp hour is still more than 5 percent below the milliamp hour on the label, consider getting a replacement as the battery will not power your electrical equipment for the correct amount of time.
Tags: milliamp hour, Li-ion 18650, Li-ion 18650 battery, using multimeter, 18650 battery, good condition, Li-ion battery
