Automatic charger control on an off-grid solar system
My house is off-grid with 6KW of PV panels on the roof. I have a custom made power-wall called a monolith. The monolith contains two PIP inverter/chargers each capable of 4KW in or out continuously. Its battery can store 20KWH of energy.
The web interface in the monolith is a raspberry-pi 2 (RPI-2) running node-red. I can modify the node-red flow to add my own features.
Using node-red I can access near real time information about the state of the monolith.
By using information such as the state of charge, battery current and charger mode I compute a cost of power (COP) in the monolith RPI-2. The COP is just a number but you can think of it as cents per KWH if that helps. With sunny weather and little load the COP is typically 30 just before sunrise and -5 after the batteries are full. I deliberately drive the COP negative to allow smart loads to turn on in a sensible order.
Node-red allows multiple node-red devices to talk over the LAN. I choose UDP ports to achieve this. Smart devices can request the COP or other information from the monolith.

My first smart load is the charger for my mitsubishi outlander PHEV (plug in hybrid electric vehicle). I bought the cheapest j1772 EV charger I could find on Ebay.
It is unbranded and cost about $220au delivered from China. It is supposed to charge at 10 or 16 amps (230V in my case) but I'm seeing slightly lower currents.

Created by eddie. Last Modification: Monday 16 of August, 2021 16:13:19 AEST by System Administrator.

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eddie, 23:20 AEST, Sun 29 of Aug, 2021: moving to new server
System Administrator, 17:23 AEST, Thu 12 of Aug, 2021: Image thumbnails not working for gallery images. Problems with the GD extension.
System Administrator, 19:44 AEST, Mon 09 of Aug, 2021: uploaded wiki and database to main server. It didn't work but the old wiki and repaired database seem to mostly work.
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eddie, 19:04 AEST, Sat 07 of Aug, 2021: testing on local RPI4 Database looks good. The online version is still broken. The server OS needs upgrading???

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