Inverter showing low battery alarm

DIY
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1

My Phoenix Inverter 12/2000 is showing the low battery alarm although my SmartBMV is Showing 12.75v for my leisure batteries and 12.66 for my starter battery. The engine will not start so there is obviously an issue with the starter battery even though the 12.66v is the normal reading and I have not had any previous issues.

Please Help

2

Poor connection somewhere. Do you isolator switches, they can occasionally fail and give poor or no connection, especially if run at high current for a while.