Victron VE net battery controller:
The VE.Net Battery Controller (VBC) is a device that monitors your battery status. It constantly measures the battery voltage, battery current, and battery temperature, and uses this information to calculate the state of charge of your battery.
Supply voltage range:9 ... 70 VDC
relay inactive<5 mA
relay active<20 mA
Operating temperature range:0 ... 50 C
Potential free alarm contact:
Rating30 V/3 A max.
Dimensions:75 x 110 x 23 mm
Net weight:95 g