question

Hi @dhoodhat

Agreed that a 300W load shouldn't do that. But the issue could have a number of causes, from dicky wiring/fuse/isolator to maybe even the batts not being charged correctly.

Have you more info you could provide, like screenshots of relevant VRM graphs or Connect history?

Are you grid-tied or offgrid? Using Assistants?

Can you check the V of each of the batts in the string independently with a multimeter?

Don't know if this helps

Don't know if this helps

@dhoodhat

It all helps, and being able now to put it all in context clears the mysteries somewhat.

You seem to have some quite massive loads (>300W!, ha), and grid-tied in parallel to your solar mppt. Does the system export, or is it all incoming? That may be important if you're exporting.

I doubt your batts are faulty, but that's a helluva load on them when solar is tapering and the grid fails. And a spurient 46V isn't of concern, unless it shuts you down of course. I run a similar size system, and 37V (the minimum) set as the shutdown point. So I never get shutdowns, just the alarms. You could do the same..

Overloads on ac-out are a concern if they last long enough for VRM to graph them. So you're using your system to the edge, which is ok if you understand that - and get away with it.

A side observation - your solar doesn't do the 'Absorb' thing, but the grid does. There may be a reason for that, but it's something that may deserve further thought.

I doubt you have much to worry about really. Just big loads on limited batt capacity & charge..