Communication using different brands

[michaeli]

I have a situation need help configuring.
I have a growatt spf5000 and two 100aH server rack batteries. Problem is they are different brands.

I have 1 eg4 pro with the breaker and the nice lcd screen and one growatt with no breaker or screen.

To get communications working I connected the growatt battery BMS to the growatt inverter and that works fine. I then diagonally parallel connected the eg4 battery for the extra capacity.

Now this all works fine and the growatt battery is communicating with the inverter. Problem is that the inverter is not aware of the second battery. When charging from solar it tells the inverter to limit charging based on a single battery (6 amps) this is a bit of a drag.

I would like to know if there is a way to connect the BMS from the eg4 battery to the BMS of the growatt battery and have the inverter be aware of both batteries.

Thanks in advance for any help.

 

[SeaGal]

I would like to know if there is a way to connect the BMS from the eg4 battery to the BMS of the growatt battery and have the inverter be aware of both batteries.

I don't see how that would be possible if they are not designed to work with each other.

One solution would be to implement a separate control system to report SOC / charge current etc. to the inverter using a Victron Smart Shunt, or similar, as detailed in this thread...

DIY Battery via Smart shunt to inverter integration (Solis etc)

Hi All, I've taken some code that handles Victron's VE.Direct protocol (Smart Shunt) and added in CAN Bus / PylonTech protocol connections, this allows the State of Charge, Voltage, Amps etc all be sent to the inverter - any one that supports the PylonTech protocol. I have it connected to a...

diysolarforum.com

Or purchase 2 similar battery packs and sell the other one.

 

[michaeli]

I was hoping that since they all use the rs485 / CANBUS that maybe there was a dip switch setting I could use.

 

[SeaGal]

I was hoping that since they all use the rs485 / CANBUS that maybe there was a dip switch setting I could use.

RS485 and, to a lesser degree, CANBus are just hardware specifications for connecting communication devices together The actual data and protocol that batteries use to exchange inter-battery information is likely to be proprietary. When multiple battery packs are connected together the 'master' battery will present the inverter with consolidated data, including the SOC and, more importantly, the rate at which to charge.

 

[Steve_S]

There are a lot of different BMS' with communications and sadly there are no International Standards for interrop YET...
If the Pack BMS' has a list of supported protocols, then maybe you can select one that is supported by the different packs and "maybe" the AIO also supports it. The most common protocol stacks are Victron (of course) and PylonTech which many support.

More info here:

Growatt Inverter + Pylontech Batteries : BMS Comms Guide

I've recently purchased and installed the following: 1 x Growatt SPF 5000TL HVM 5kVA/5kW Hybrid Inverter. 2 x Pylontech US3000 batteries. 1 x Pylontech cable kit with RJ45 BMS comms cable included. I've just spent 5 days communicating with Growatt in China to figure out why I could not get the in...

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