question

Batteries are 8 years old, seem okay, could they be causing a problem ,?

8 years is well over the life expectancy of any batteries I'm aware of (though Battle Born does currently offer a limited 8-year warranty); good for you for treating your bank well enough to make it that long! As with any battery, however, the total capacity of the battery diminishes over time and with use, so it's very likely that your battery bank no longer has enough current throughput available to fully compensate for the inrush demand when you plug in your appliance... it definitely sounds like you're getting a significant voltage drop in that first millisecond when your load turns on, which -if the drop is significant enough- would cause your Multi to throw an error and/or reset itself.

Besides fixing the slight damage on the neutral of the AC out as you mentioned above, I'd definitely look to replacing your battery bank; there's a very good chance that'll fix your problem. All that being said, of course there's a possibility that the Multi is finally on its last legs, but my own experience with Victron components leads me to suspect literally every other component in a system before I suspect the Victron.

Good luck!

Right, I have now had a visit from a Victron Engineer, as you would expect everything was working okay ! He suggested that the battery's could be the problem as they're eight years old, we have now fitted two new 170 ah. Victron super AGM batteries, still having the same shut down problem as described in my original post, have now taken off the blk & red temperature sensor lead and all seems to be working fine, could it be a faulty sensor ?