Raspberry Pi between Cerbo Auto-Start relay and Generator...

[AlaskanNoob]

Unless there is an easier way, I plan to connect a Raspberry Pi to the Cerbo GX Relay #1 and hopefully provide the 5V of power it needs. The intent is:

a) when Cerbo sees battery bank at 40% it will energize the generator auto start relay

b) that relay will then power the Pi

c) the Pi will then boot up, connect to the Cerbo GX over WiFi, and run a MQQT server that will pull current Charge Limit, minimum battery temp, and MPPT current

d) if the Charge Limit - MPPT current is at least 100A, the Pi will then energize a two wire relay to the generator which will start the generator and power an EG4 chargeverter connected to the bus to charge the batteries

e) The PI will continue to monitor and if there is any danger of the Charge Limit being exceeded, it will shut off the generator

f) when the batteries are charged to 50%, the Cerbo will shut off the Relay 1 which will shut down the Pi and the generator

This should solve the problem of the EG4 charging the battery bus directly without talking to the Victron system which can control its output (risking over current at low temperatures).

Unfortunately, while the Cerbo GX can see the Charge Current Limit the BMS puts out, I can't tie that into the generator auto-start functionality. So I need to make my own.

Anybody done anything similar?

 

[Adam De Lay]

I haven’t done this, but it sounds like you want to take a look at NodeRed for the Cerbo. You can create custom, conditional functions to trigger almost whatever you want.

 

[rhino]

I haven’t done this, but it sounds like you want to take a look at NodeRed for the Cerbo. You can create custom, conditional functions to trigger almost whatever you want.

What Adam said.. you have to switch to the Large image. Go to the Remote Console like image below and follow Settings->Firmware->Online updates->Image type. You probably have "Normal" selected and you want to change it to "Large". Large has Node RED installed. Follow https://www.victronenergy.com/live/venus-os:large for more info.

 

[AlaskanNoob]

Thanks for pointing that out. That would be much simpler.

I just have to confirm the CCL and MPPT RS Charge Current values are exposed in Node Red and, if they are, I'll do it that way. Much better. Many thanks!