How Battery Isolator Works:

Off-roader/caravan vehicle usually need to be equipped with a second battery to meet the demand for electrical appliances in the car. However, the second battery cannot be directly connected in parallel with the original car battery. On the one hand, the stalling use of electricity is prone to cause the original car battery to lose power and it is difficult to start the vehicle. On the other hand, the line load is too heavy while the two batteries charging together. Therefore, a battery isolator is required.
The battery isolator, also known as a split charge relay, uses your vehicle's power to charge an auxiliary battery and blocks your starting battery from getting drained by your equipment when the engine is turned off. The auxiliary battery isolator will only allow the extra battery to charge at whatever rate the alternator can manage.
Specifications:

Input Voltage: 12V/24V working voltage and load voltage
Continuous Current: 250A normally open
Peak Current: 250A normally open
Automatic Connection Voltage: 13.5V-16V (12V working) / 27V-32V (24V working)
Automatic Disconnection Voltage: 12.5V, immediately disconnect if below 12.5V
Over Voltage: 16V/32V
Weight: 694g
Size: 15.2*14.7*4cm /6*5.8*1.6inch
Note: Please do not put the product under the water situation.

Packet:

1 x 250A Smart Dual Battery Isolator
1 x English User Manual