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Solar geyser with SR81 controller automation

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Hi,

Around 13 years ago we installed solar geyser with evacuated tubes that utilizes SR81 controller (touch wood still works well).

Working from home gave me opportunity to switch on geyser when batteries are full and store excess energy, which works great but I would like to automate whole process.

I have HA running using @kellerza setup to get all the info from Inverter, weather forecast and few extra bits (just installed CBI astute to control pool pump).

Function wise I would like that HA can switch on heating element and set max temperature (for start).

Did anybody hack SR81 so far, if I would like to do it where to start (decode protocol, point me to any direction)(I'm handy with c\c++, python)?

Cold SR81 be replaced with maybe Geyser wise delta wifi enabled unit (or any other unit) ? Basically I keep geyser and panel temperature sensors, device can power heating element and water pump that circulates water.

I would appreciate any input!

 

Thanks!

 

 

 

  • 11 months later...

@alex71,

I Googled SR81 controller, and see it is a similar controller that I have on my EV Tubes. Mine is a TK-CS6, and seems to differ slightly. See RH side on pic. the LH side controller is an Alliance Heat Pump controller, both systems from around 10 years ago.

image.thumb.jpeg.7eceac26ba04edf130e4df3808a12033.jpeg

Both controllers have a 3/4-wire connection, which I assume to be GND, +5/12V(power), Rx & Tx, so my assumption is normal RS232 on common bus. See below

image.png.85f6030541a9d1d5f731cd90b234c66c.png

As per OP, I would also like to integrate (i.e. control) these 2 devices into HA, which I use to control/run my Solar System.

The HP is unfortunately also elderly, yet very functional, and does not seem to have an additional comms port (for a ESP32 wifi setup)

If anybody has any info on how to "tap" into these devices, please let us know your findings.

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