question

With the Pylontech Force-L2 batteries the BMS does indeed cut off the battery when the on-load voltage gets down to 47.0V. But there is a lot of hysteresis so it then requires a considerable amount of charging to reverse this to normal operation so is best avoided.

It would be good to be able to use Dynamic Cut-off to keep out of this operating area in a way that takes account of the internal resistance (about 30 mohm per 3.55kWh module). However the recommeded setting of 46.0V is too low for it to work, as described in this thread. (Since then I have added more PV and a third module but it has not directly solved this issue).

So in the end I programmed my 5kVA Multi using Node Red to taper the allowable inverter power from max at 48.0V down to zero at 47.2V in 5 steps.

This works OK - but it is a pity that Dynamic Cut-off doesn't, as it would have been a lot easier to do it that way. Increasing the range over which you can set the cut-off voltage ought to be a simple change for Victron to make.

@thanar states this ... as reasoning why dynamic cut off has no place in an ESS using Li chemistry cells.

"Because Lithium batteries have a build-in BMS that will block discharging when the battery's minimum threshold (or a cell's) is reached.

But the above simply isn't correct, perhaps all Victron LI chemistry cells do have internal management systems, but there's a vast amount of ESS's built using all manner of modular cells that do not have, nor need, built in managements systems.

Perhaps I misunderstood your comment, and perhaps you have misunderstood my reply.

You said "build-in" ... which implies internal, self contained ...

I have 250kWh of ex EV cells, parallel MPs and a REC BMS, I see the dynamic cutoff feature as a useful, but seldom if ever used feature.