In brief: I got really annoyed with the standard
battery monitors that are in general completly useless except showing
current volts and amps ( amps not very correct usually) costs a fortune, dificult to install
cables to lay etc. following is a description of a completly working open source - free
project - everyoine who is interested and want to build one for himself I'm happy to help with
advice and everything needed ...
project - source files and description located at :
https://github.com/vtomanov/merix
in :
https://github.com/vtomanov/merix/tree/master/pics - are some pictures of the actual working thing
Brief Capability Description:
- up to 9 measuring point ( easy extensible with just a configuration change if needed)
- every measuring point can be included or excluded in the
current consumption, current amps and volts calculation - for example if you have let say one measuring point just after the
battery bank and somewhere further down a measuring point which will measure the
watermaker consumption - you do not want the
watermaker to be included in the current calculations as it is already part of the first measuring point, but in the same time you do want to know how much the watermaker consumes and how much from the total consumption it is accountable for.
- measuring point communicate with the main/display module using radio/wirelessly
- calculate properly the in and out amps and adjust based on the battery voltage when appropriated
- calculate/adjust dynamically the loss coefficient as to get 1ah to discharge you actually need to charge more then 1ah - and the loss increases when
batteries become older
- show the consumption for the last 24h
- shows how much time is left until the
batteries are down to 50%
- shows how long it will take to charge the batteries to 90%
- shows current AH available in the batteries
- shows charge state in %
- shows amps, volts and for how much of the discharge or charge every measuring point is accountable for
-
screen is able to switch off the back light to prevent the annoying strong light source during sleep in the
saloon
- able to initialize and connect new measuring points ( handshaking and binding with all available measuring points)
- reset of all measuring points and enables them for new binding with new main module or etc.
What The Display Show:
First line:
- average voltage across all measuring points
- total resulting current ( sum across all measuring point)
- proper calculation of battery bank state of charge ( with correction when volts are over 14 and no consumption or charge, when no consumption or charge for 1min also charge state correction based on voltage) and when charge state is corrected - auto calculation of
lost coefficient while
charging - e.g. when you charge there is a loss e.g. to have 1ah to discharge in average you need to charge 1.25ah)
Second line - flips between ( every 5 sec - configurable) :
- total AH available , and total consumption for the last 24h
and
- time to discharge to 50% ( if discharging) or time to charge to 90% if
charging - assuming charge or discharge current continue to be the same ( the charging calculation is a proper one taking in account that after 75% charge the batteries gradually start accepting lower and lower current)
Third and Fourth line are related to cycling between all measuring points
Third line - name of measuring point and :<sequence> of the update received from the
sensor
Fourth - current voltage at this measuring point, current amps at this measuring point, how much consumption this measuring point is accountable for in % from day one.