Product Review

Specifications: 
Charging voltage:16.8v ~ 18.1v
Over Charge voltage:4.25±0.05v
Over Discharge voltage: 2.5v±0.05v
Continuous discharge current (upper limit): 40A (if the cooling environment is not good, please reduce the load current )
Continuous charge current (upper limit): 20A
Internal resistance: Less than 100mΩ
Working temperature:-40 ~ +50Celsius
Storage Temperature:-40 ~ +80Celsius
Weight: 8.8g
Size:46 mm×60 mm×3.4mm/ 1.81″ ×2.36″×0.13″
Detailed electrical parameters are shown in the picture
Suitable for:  
1.Suitable for lithium batteries with nominal voltage of 3.7V and full voltage of 4.2V (including 18650, 26650, polymer lithium batteries, no size limit)
2.Suitable for electric drill with starting current below 80A and power below 135W .
Attention:  
To successful starting the drill requires four 15C-20C power batteries, or eight 10C-15C power batteries (ordinary 18650 battery can not start the drill!! Recommended power battery models: SONY VTC4, VTC4A, VTC5A, VTC6).
When you wiring 0V, 4.2V, 8.4V, 12.6V, 16.8V, plese do it strictly according to the wiring diagram. Do not deliberately make it short circuit.
When using a brush motor type load, try to connect a non-polar capacitor (withstand voltage above 25V, capacity 10uF-100uF) in parallel with the positive and negative terminals of the motor to prevent the reverse spike voltage generated by the motor from interfering with the protection board or breakdown of the MOS tube.
When soldering the battery for the first time, do not connect any load or equipment to the output.
Do not mix the good battery and poor battery to use.
The internal resistance of 4 battery capacity are closer will be better.
Package inlcuded:  
1x 4S 40A lithium Battery Protection Board