High voltage BMS to connect 400V battery from car for a house battery

Hello Batrium community, thanks for allowing me to join.

I am interested in using a battery from an electric vehicle / BEV (BYD Atto 3: 400V, 126SP1 LFP prismatic cells) to connect to a hybrid inverter for home storage. I have yet to purchase the inverter, so would be happy to get one that works with Batrium, maybe a 30kw 3 phase Sungrow, Deye, Goodwe, Fronius or similar. The end goal is to build my own tesla powerwall at 1/4 the cost per kwh. connect it to Amber Energy with Home Assistant/EMHASS to automate it to export of energy to the grid when the FIT is high and charge from solar panels or grid if the cost is low.

What would the Batrium community recommend to do this?
Is there a native integration into the BYD BMS that can translate the temps/cell voltages/amps to the Inverter? Or will it require opening up the pack and attaching a lead to each 126 cells?

Thanks in advance.
I look forward to your ideas.

Tinman in Sydney.

Hi Tinman,

We have a number of customers doing this, so you’re in the right place :slight_smile:

We can emulate the 3 main protocols HV inverters expect (BYD HVS, LG RESU and PylonTech HV), so you have a wide range of inverters to choose from.

We don’t have an integration with the existing BYD BMS, so you would need to run balance wires to all cells, yes. We’re aware of that as a use case, and we’re working on a product to do that.

If you have any questions, let me know :slight_smile:

Hey, for me Pylontech HV and BYD HVS is working fine. The limits are transmitted correctly. I switched from Deye SG01HP3 to a GoodWe ET inverter. The Deye was not able to fully charge the battery. Every time it gets near 100% it randomly started to discharge with full power (no alarm flags were set). With the GoodWe, I had no problems. The limits are transmitted correctly and fulfilled by the inverter. Inverter DC input also goes to standby, if charging current is set to zero. This was not possible with the Deye high voltage hybrid inverter.
If you search for ‘Deye hybrid inverter high voltage firmware’, you will see that there are many problems. The only way I would operate the Deye hybrid inverter is with their own high voltage battery with its BMS. I also made a video with the problems that I observed:

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From other people experiences I can also say that Fronius and SUNSYNK is working. SUNSYNK is the same hardware like Deye, but with other software.

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