Nice one 'noneyabussiness'.
Yea, getting a quality tx and rx, and good code set up, that actually works and lasts is excellent.
Moderators please, feel free to make the below more grammatically correct and better English.
Those of you who are not sure whats going on here, its all about AC coupling used/old GTI's, (Grid tied Inverters).
Normally ordinary GTI's are designed to be Grid Tied into your utilities supply, and push the voltage up a few volts and back feed to your utilities at a local level, and your meter goes backwards, (it may not, but you get the drift).
When you have an offgrid system, normally its PV etc, to DC charge controllers that then charge batteries and the batteries run your Power Inverter , ie 24vdc or 48vdc to 120vac or 230vac.
A bigger system that has over 800ah of batteries can now work with GTI's AC coupling if your Power Inverter is a H Bridge design. Ac coupling simplifies the system.
So your GTI is now connected to your 120vac or 230vac, that your Power Inverter is creating. The GTI needs to see a good stable HZ and stable AC voltage.
Once your GTI is gone through its start up procedure and is happy, it then feeds into your Power Inverter created Mini Grid, and the power can be used. However, power not being used by the Mini Grid is then pushed back through your Power Inverter and charges your battery bank.
There are some rules/criteria that must be followed with this type of AC Coupling arrangement.
Most old/used GTI's are MPPT and are fairly robust, well mine are, and its a cheap way of getting extra power from a RE source like PV etc.
What 'noneyabuissness' has done is devised a system that controls the GTI and shuts it down if the battery bank is fully charged and no power on the Mini Grid is being used.
I use Voltage comparators that watch the battery voltage at each GTI to shut them down, or i manipulate the GTI's internall settings, so instead of the GTI going to say the normal 256vac push back into your Mini Grid, i can set the GTI to shut down at 247vac.
There are other ways of managing the GTI's, but a wireless dependable system where the GTI could be on another building 700 feet away and does not need a data cable, that is along side the 120vac or 230vac power cable from the main battery bank and Power Inverter, is good.
'Noneyabussiness', I look forward to looking to your photos and write up. Thanks.