Reading the capacity of a rechargeable battery
1500mAh rechargeable battery, fully charged. Discharge current 1500mA can reach 1 hour to indicate capacity is enough. Still use 750mA discharge to test for 2 hours. However, when the voltage is 0.9V (1.2V rechargeable battery), there is still a nominal current discharge, how to understand. What we mean by battery capacity actually refers to the capacity of the battery. In other words, when the 1500mAh rechargeable battery is discharged from 1.45V to 0.9V, the discharged electricity is the capacity we need. The discharged capacity below 0.9V is not used, and the discharged electricity is not much (discharge is too low. Will also affect the battery life), generally good discharge battery discharge platform is better, such as: 1500mAh battery from 1.45V to 0.5 C's current discharge is set to 0.9V and released for 120 minutes. Then we say that the battery's capacity is 1500mAh. The relationship between current and voltage in this period of time is shown as: Note: I: Ampere or milliamp; f: [1/h], often only say \"number\" when narrative, not the unit; C: Battery capacity, unit: Ah or mAh. For example, when the battery capacity is 800mAh, charging with 0.1C current is equivalent to clear: Charging current to the battery I = 0.1 [1/hr] X800 [mAh] = 80 [mA] f is also called \"n hour charge (discharge)\", f = 1/(n hours) Measuring battery capacity is generally measured battery voltage. The charger detects the battery voltage during charging, and assumes that the voltage is full when the voltage reaches a specified voltage value. If the lithium battery voltage is charged to 4.2V, it is considered full. The voltmeter accuracy of the detection voltage must be 1% positive or negative. Lithium battery is damaged due to overcharge. If you want to monitor the battery charge and discharge, the book has a very mature circuit can refer to, if you just measure it, then it is easy to handle, according to the capacity to calculate the load resistance, discharge with the standard discharge current, then detect the voltage, as long as Meet or close to the nominal discharge time. Sensen Group Co., Ltd.  , https://www.sunsunglobal.com
The discharge platform of a good battery will drop rapidly after 0.9V, so the amount of electricity discharged in a short time is very small. On the contrary, when the bad battery discharges from 1.45V to 0.9V, the voltage drops quickly, and after 0.9V, the voltage drops again very slowly. This type of battery has poor performance and the general capacity is also very low.