Three terminals of baaterries are- GND - Ground
- BSI - Battery Size Indicator
- VBAT+ - Battery positive terminal
Whats is Battery Status Indicator (BSI) ?
- The battery block contains BSI resistor for battery identification. The BSI fixed resistor value indicates the chemistry and default capacity of a battery. Temperature and capacity information is needed for charge control (charging current and the voltage).
- It is connected to resistor to GND. The phone measures the resistance of the BSI - GND connectors, and it can determine which kind of battery is in the phone.
- There are some mobile phones, which has shorter BSI pin. It is because when the battery is being removed when the phone is turned on, the BSI circuit interrupts first, which tells the processor to shut down all communication to prevent damage.
Examples:
Nokia NiMH batteries:
- BMC-2 640mAH 3.3 kOhm
- BMC-3 900mAH 5.6 kOhm
- BLB-2 650 mAH 68 kOhm
- BLC-2 900 mAH 75 kOhm
- BLS-2N mAh 50 kOhm
