The Victron BMV Battery monitor is used to monitor battery systems and report back on voltage, current and state of charge as well as some additional battery attributes.  For Engineering applications is is useful to be able to export this data to a computer program where it can be analysed.    The Victron BMV Reader software is set up to do just this.  To connect the BMV to your computer you will need to Victron VE Direct to USB interface.  

To get started you will need to go on the Victron Energy Downloads Page and download the BMV Reader Program and its USB drivers.

Download the BMV reader program and its drivers

Then you connect your VE Direct to USB adaptor between the meter and your computer:
VE Direct to USB

When you start up the BMV Reader software you may have to figure out which port it connects on since it doesnt do this automatically.  Once you get connected the main screen will look like this:

BMV Reader main screen

This screen is summarizing all the information available on the system, you can make a log file by going to FILE > SAVE TO CSV and then it prompts you to select an interval for the data log.  In the example below I selected a 5 second interval which gets me a rather big file, but you can select an appropriate interval for your application:

Output settings for data log file

Here is an partial screenshot of the file generated:

Data file screenshot

The headers of the file correspond to the data in the History section covered in the Instruction manual for the BMV

V is battery voltage
VS is aux battery voltage
I is current in Amps (+ Value means charging, - Value means discharging)
CE means consumed energy in Amp Hours
SOC means state of charge in %
TTG means time to go (to full if charging or to empty if discharging)
ALARM is a programmable value
RELAY is a programmable relay contact (on-off)
H1-H16 are historical values defined in the instruction manual

The Victron VRM

Another way to monitor batteries where an internet connection is available is by using the Victron VRM remote portal   This requires the Venus GX as the internet gateway.  Data can be monitored from anywhere in the world in real time.

Other options

This same technique can be used for remote applications with the aid of the Victron LoRaWan interface.  This allows for wirelss transmission of data over a wider range than conventional WiFi using the "Internet of Things"  It is suitable for low data rate transmissions, typically one transmission per hour.