We have a fairly new set up on our narrowboat with 2 X 150 AH Lifepo4s. Charging from engine or solar. We are using a relatively low amount of power, and the batteries have barely been below 80% charge. A couple of weeks ago we noticed the system seemed to shut down for no obvious reason. At the time we thought it coincided with new appliances being added, eg a 12v fan or using a new tool/phone charger (via the multiplies). Now it is more frequent and we think is linked to charging and battery temperature. It happens when we enable the solar to charge or when we run the engine to cruise or heat water in the calorifier. And it always happens when the batteries reach around 26 degrees or go above this. The red LED (Cell <4V or temperature) on our VE BUS BMS comes on at the same time. Whatever it is, this doesn't seem like it should be a problematic temperature, but as soon as the system shuts itself down we're then powerless to do anything; either to investigate the issue, or to use basic on board facilities.