Many products from Victron Energy (www.victronenergy.com) seem to implement their "VE.Direct" protocol, which allows remote monitoring (and some control) of those devices. At its simplest (monitoring only), VE.Direct is a 19200 baud ASCII stream of keyword/value pairs, reporting various parameters (voltage, current, battery capacity, etc) from the device. The monitoring protocol is specified here: https://www.victronenergy.com/support-and-downloads/whitepapers (search for "VE.Direct Protocol") with a little more information here: https://www.victronenergy.com/live/vedirect_protocol:faq
This script (called, imaginatively, "ve.direct") captures that stream of data, implements a (relatively primitive) display of the important parts, allows logging to a CSV file for later plotting, and, most importantly for me, allows remote access by acting both as a network server for the data and as a client that can receive the data either directly or remotely. There's also a facility for keeping a backup copy of the data, in case you want to reprocess it.
The "primitive" display simply takes over your terminal window and presents this simple display (from my BMV702 battery monitor):
Voltage 12.358 Volts Current 0.259 Amps Power -3.20 Watts Charge consumed -17.867 Ah Capacity left 93.9 % Time left 10d 0h 00m Time since full 2d 6h 54m 03s Battery temp. 51 degF
The CSV file contains lines like this:
# date/time, mV, mA, W, %charge (x10), time-left (sec), degrees C, alarm-reason 2016-11-17-17:20:04, 12359, -258, -318, 939, 14400, 11, 0 2016-11-17-17:20:06, 12358, -254, -313, 939, 14400, 11, 0 2016-11-17-17:20:08, 12359, -260, -321, 939, 14400, 11, 0 2016-11-17-17:20:10, 12357, -276, -341, 939, 14400, 11, 0 2016-11-17-17:20:12, 12358, -252, -311, 939, 14400, 11, 0 2016-11-17-17:20:14, 12358, -262, -323, 939, 14400, 11, 0
The specific contents of both of the above are trivially changed in the code.
(Victron also has an interactive command/response protocol, described in other papers at the above link. This script doesn't do anything with that. See the "HEX Protocol" documents at the above link.)
The client/server aspects are based on ssh, so the security implications of connecting to a remote host to get battery data are minimal.
And, just because I enjoy it, and usually learn something new when I push the boundaries of the language, it's all implemented in bash.
paul fox, autumn 2016