AC500 Error 103 BMS Communication Error


I have two AC500 units and while setting them to dual phase received error 103 BMS Communication Error. I disconnected the communication cable, and returned each unit to single phase, but the error will not clear. I then upgraded the firmware, and still no luck.

Anyone have any thoughts or solutions?


Hi @Rria1965 , This error may be due to a loose communication cable, can you please confirm if the communication cable is plugged in tightly? Thank you.

Good Morning,

Unfortunately I disconnected the cable thinking this would clear the error. Should I reconnect the cable and attempt to clear the error again?

Thank you,


Good Evening,

I was able to clear the error by reconnecting the communication cable.

Thank you for your patience!

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