Victron ESS Annoying 3% Hysteresis on Battery Charging

[1201]

Also, follow up question-why do you prefer ModbusTCP to MQTT?

 

[ricardocello]

This is seriously crazy- and I mean in a good way.

So Victron essentially gives you virtually unlimited control over how your inverter acts in a way that almost no other systems have?

Honestly, this is the one of the main reasons I went with Victron. Not for the blue color (don’t tell Eggo).
Although I design hardware, I like coding too.

As for other systems, many inverters and MPPTs give you access with Modbus, but it is hit or miss depending on the vendor.
Getting official documentation can be challenging, sometime you have to reverse engineer it.

And they use ModbusRTU, which is just RS-485 physically, so not nearly as convenient as Ethernet.
It’s also not centralized like Victron does with the Cerbo GX.
That’s why lots of people without Victron don’t understand the need for a Cerbo, the AIO does everything.

I don’t know about EG4, I don’t think they let you play at all with their registers.
Maybe if you sign an NDA.

Found it, EG4 18kpv modbus registers:

https://www.dth.net/solar/luxpower/modbus/EG4-18KPV-12LV-Modbus-Protocol.pdf

Just scanned through it. There’s a lot of work if you want to code for that thing.

So, one limitation I hate that Victron has is that you can't set it to sell from battery to grid in an intuitive way.

That’s certainly true without ESS (cause it’s impossible).
It’s not intuitive with ESS either.
With DESS it might be easier, I don’t know.

How would you achieve this with programming?

Assuming ESS is installed, you could poke the minimum SoC lower to force battery discharge to loads and grid.
You would have to write a scheduler to have it happen when you wanted.
There’s probably other ways too.

When given 100 knobs that can be adjusted, sometimes you have to be creative.

 

[ricardocello]

Also, follow up question-why do you prefer ModbusTCP to MQTT?

Because I’m an embedded bare-to-the-metal engineer, and I’m comfortable there.

MQTT is modern and superior to Modbus in every way, and if I were doing it from scratch, I would use it.
It integrates well with HomeAssistant too. I’ll get around to it eventually.

 

[1201]

Honestly, this is the one of the main reasons I went with Victron. Not for the blue color (don’t tell Eggo).
Although I design hardware, I like coding too.

As for other systems, many inverters and MPPTs give you access with Modbus, but it is hit or miss depending on the vendor.
Getting official documentation can be challenging, sometime you have to reverse engineer it.

And they use ModbusRTU, which is just RS-485 physically, so not nearly as convenient as Ethernet.
It’s also not centralized like Victron does with the Cerbo GX.
That’s why lots of people without Victron don’t understand the need for a Cerbo, the AIO does everything.

I don’t know about EG4, I don’t think they let you play at all with their registers.
Maybe if you sign an NDA.

Found it, EG4 18kpv modbus registers:

https://www.dth.net/solar/luxpower/modbus/EG4-18KPV-12LV-Modbus-Protocol.pdf

Just scanned through it. There’s a lot of work if you want to code for that thing.

That’s certainly true without ESS (cause it’s impossible).
It’s not intuitive with ESS either.
With DESS it might be easier, I don’t know.


Assuming ESS is installed, you could poke the minimum SoC lower to force battery discharge to loads and grid.
You would have to write a scheduler to have it happen when you wanted.
There’s probably other ways too.

When given 100 knobs that can be adjusted, sometimes you have to be creative.

If the grid setpoint is set to a negative number will it discharge to grid? If that could be automated it would achieve the goal

Because I’m an embedded bare-to-the-metal engineer, and I’m comfortable there.

MQTT is modern and superior to Modbus in every way, and if I were doing it from scratch, I would use it.
It integrates well with HomeAssistant too. I’ll get around to it eventually.

Ok got it. That's why I asked, lol, because home assistant has a pretty robust mqtt implementation

 

[ricardocello]

If the grid setpoint is set to a negative number will it discharge to grid? If that could be automated it would achieve the goal

Ah! Yes, yes it will!
I never do that though.

Ok got it. That's why I asked, lol, because home assistant has a pretty robust mqtt implementation

I have HA running on the desk here, have not integrated with any solar gear yet, just cameras and Shelly switches.
I'll get there eventually. It won't interfere with my existing Modbus stuff either.

 

[Brucey]

Not sure if this helps pretty good intro into node red:

An Introduction to running Node Red on the Cerbo GX

 

[ricardocello]

Not sure if this helps pretty good intro into node red:

An Introduction to running Node Red on the Cerbo GX

And that's yet another way to do it, and it is fairly popular.
It does require a different install on the Cerbo, however.

Graphical programming tools just aren't my cup of tea.
I've used LabView and GNUradio (not for solar), and they're ok for that sort of thing.
The advantage to node-RED is the visual representation, which can be easier to follow.

 

[Brucey]

I think you just turn on large image, let it download latest update and then enable node red?

 

[ricardocello]

I think you just turn on large image, let it download latest update and then enable node red?

Yes, VenusOS Large image

Venus OS Large image: Signal K and Node-RED [Victron Energy]

www.victronenergy.com

 

[ricardocello]

Script is now running on the Cerbo GX automatically.

Yesterday was a beautiful day, so my loads were way down, and I ran out of battery space at 1pm. 32 kWh for the day.



Today was colder, more loads, 38 kWh for the day.