MultiPlus gets huge voltage drop with any significant use

[Djk]

I’m running a Multiplus 12/3000/120 connected to 3 diy 280Ah 12v LiFePO4 batteries, each with a Daly 150 BMS. Batteries run in series to a lynx distributor, then to the inverter. 4/0 wires the whole way. The inverter does fine with light loads, but if I put any decent load on it, I get a huge voltage drop and the inverter cycles off. For example, if I put an 1800W induction cooktop on, even at partial power, the voltage at the Multiplus drops to 10.2 v and the inverter cycles off. Even if the Dalys are overrated, it seems like I should be able to pull 150A off the 3 batteries no problem (no other load on the batteries).

I’m not certain where to look for a failure point for or diagnostic steps. Any advice is appreciated. In case it’s helpful, I’ve attached the BMS settings. Thanks!

 

[sunshine_eggo]

Triple check that each and every connection, including cell interconnects, are properly torqued.

 

[rmaddy]

Batteries run in series to a lynx

I do hope you mean parallel, not series.

 

[jberger]

Do you have a victron shunt on the neg side to compare with the reading of the Multiplus?
Shunts are usually more accurate than the inverter.
What does your voltage drop look like at each connection?

 

[Djk]

I do hope you mean parallel, not series.

I did, thanks!

 

[Djk]

Triple check that each and every connection, including cell interconnects, are properly torqued.

That did it, thank you!