1. Check the label of the 18650 lithium-ion battery to confirm that its output voltage is 3.7V, but the capacity may be higher or lower than 2000mAh (some are 3000mAh)
2. Find the positive and negative of the 18650 lithium-ion battery. The round shape of the protruding button of the battery is the positive terminal of the battery, and the flat bottom position is the negative terminal.
3. Use a multimeter to check the output voltage. Make sure it is set to measure voltage. Place the small metal rod at the end of the red cable onto the positive terminal of the 18650 lithium-ion battery. Place the metal rod at the black end of the multimeter onto the negative terminal of the battery.
4. Display the multimeter display panel. If the battery is in a normal condition, it should read between 3.6 and 3.7 V. If the reading is lower than 3.5 V, fully charge the battery. If it is still infbelow 3.5V after charging, this means you need to replace it, as these are signs that the battery charge is slowly decreasing.
5. Check the battery capacity, set the multimeter to measure the amount of current flowing per hour, and place the two metal rods on the positive and negative metal ends of the battery.
6. Check the multimeter display. The mAh of a fully charged 18650 Li-ion battery as labeled indicates that the battery is in good condition.
How to reflect the good performance of lithium batteries? How to identify the quality of batteries on the market?
Generally, detecting problem batteries in problem modules mainly relies on the following points:
1. Appearance, if there is a leak. Flatulence. Problematic battery cells sometimes have obvious side effects, and the battery cell presentte obvious appearance abnormalities;
Battery bulge
2. tension. This can be measured with a multimeter.
3. Internal resistance. If solder breaks or other reasons occur inside the battery, it will also obviously be reflected in the internal resistance of the battery.
It is actually not recommended for ordinary people to deal with battery failure, because the electrolyte inside the battery poses certain dangers. If not disassembled properly, it may catch fire or even explode.
In addition, voltage and internal resistance testing generally examines outliers. The battery cells in question generally have a significantly lower voltage and a significantly higher internal resistance.
How to use a multimeter to test the quality of lithium batteries
The key performance of lithium batteries is high current capacity, but mAH marked on the lithium battery is the capacity at low current, it will drop less under high current. Generally, a good battery will be less than 10% to 20%, and a bad battery will be less than 50%. Lithium-ion polymer batteries would be only 5% less efficient. It is difficult to test the performance of the purchased battery. If you must test it, use it after fully charging it. Cell phone battery keeps talking, camera battery keeps blinking. Recharge after exhausting the battery, at least 10 times. After 10 times, compare it with a good battery. If you think the usage time is okay, you should be fine. However, this testing method is not very accurate.
Then there is a leakage current, which corresponds to the automatic discharge of the battery. ChargingIt is difficult to check when the battery is fully charged, you usually need to discharge itger until it is discharged. Lithium batteries are generally 3-3.5V. Then leave it for a while, usually a day, and the voltage will increase a little. If left for a while, the tension will drop a little. At this time, the voltage drop is not very obvious and the battery is of good quality.
Use a multimeter to measure the voltage of your cell phone battery. Touch the red test lead to the DC 10V level at the + terminal of the battery and the black test lead to the - terminal of the battery to read the battery voltage. Generally, the battery voltage of mobile phones is 3.7V. Under normal circumstances, a good battery will be 0.3-0.5V higher after being fully charged. Generally, cell phone batteries are equipped with overcurrent protection and low voltage protection circuits. When the coBattery output current is higher than the battery rated current, the circuit will automatically disconnect the circuit to protect the battery and prevent it from exploding due to rapid heating due to battery short circuit. Use a multimeter at DC 10A level to. test whether the battery protection circuit is effective. The method is to adjust the multimeter to DC 10A level and connect the red test lead to the + pole of the battery, connect the black test lead to the - pole of the battery and pay attention to the response of the reading of the multimeter. If a reading flashes and then immediately returns to 0, this is normal. I hope this answer is helpful to you