Victron BMV-700:
The BMV-700 is a high precision battery monitor. The essential function of a battery monitor is to calculate ampere hours consumed and the state of charge of a battery. Ampere hours consumed are calculated by integrating the current flowing in or out of the battery.
Data sheet:
https://www.victronenergy.com.au/upload/documents/Datasheet-BMV-700-series-EN.pdf
