Hi All
Our muni has moved to a “Rand charge/amp of supply” model and I am keen to limit my draw from the Muni. I have a 20a option for breaker size.
Currently Power Assist on the Multi II is set to off.
Is it worth setting Power Assist to On for those times when I need to use more than 20a from the muni and supplement with the battery as needed?
I have read all the docs and community posts and feel it’s needed - I would set the Input Current Limit to 20a on the GX as well.
If you don’t have a grid meter, then just set the AC input current limit (in VE.Configure) to 20A, and leave the GX setting alone.
If you have a grid meter, then set the limit on the GX to 20A, and you might as well leave the one on the inverter itself alone (especially if you have AC-coupled PV in front of the inverter).
As usual, the implementation in the Multi is way faster. But breakers only trip instantaneously if you exceed 500% I_n.
If the battery reaches ESS minsoc, it stops shaving the peak, unless you enable the option to allow peakshaving under minsoc. If you enable that option, note that the Multi will use significantly more battery power at minsoc, because it cannot turn off the “bridge”, it has to keep it alive in case a peak has to be shaved.
So do I still need to check Power Assist (leave Boost Factor at 2.0) in VEConfig?
Technically you don’t have to… when you use the GX implementation with the grid meter, then it calculates setpoints that will result in a current that should not exceed 20A, and as long as nothing prevents the Multi from doing that (eg running too hot, a BMS limiting discharge power, SOC being too low), it will do it.
If you do enable both (leave the boost factor at defaults… I don’t know exactly what it does, it is fine at the default), then the one configured on the Multi will apply to the input of the Multi (so loads on the output of the Multi will pull from the battery to keep the input below the limit), while the other one will apply to the overall grid connection measured at the meter. It goes without saying that if you configure the one on the Multi too low… you can shoot yourself in the foot.
Edit: Example, we have a customer that has an EV charger on the output of the Multi, and a PV-inverter on the input side. He wants the grid limited at 20A, his EV charger can pull up to 40A, and his PV-inverter (in full sun) can provide an addition 20A or so. He therefore must set his AC input current limit (the one in the Multi) to no less than 40A… otherwise it cannot import the full 20A from the grid plus the 20A the PV-inverter is making. He does however like to put another limit there, as a kind of belt-and-suspenders approach.
Dankie Meneer!
Still getting my head around the different “views and angles” 
I will not tell you how much my head hurt writing that… this is one of my least favourite bits of code. It is C++, which I’m fine with, but you do a lot of FOR loops do shuffle things around (because, for example, adding a QVector to another QVector… does not do what you think it does). Very very hard to do things in, and then the PV limiter is also glued into the same project, a total PITA to split out.