Victron Power Assist & Voltage Sag

JayBeavers

I have a 'semi-grid' situation where I bought an older house (1958) with a really old grid feed (25 kva grid transformer, shared with a neighbor) and my local grid energy provider has been unable to upgrade the service (been 18+ months...)  We have heat pumps and electric stove and four EVs, so it's been a challenge.

I addressed the challenge by adding a pair of Quatro 10 kva inverters for split phase with 5x 48V 100Ah batteries, then putting it into Power Assist mode.  This is great because my grid power can easily provide 'watt hours over time', even when it can't service my house's peak demand.

The challenge I'm running into is that during peak demand house when my grid transformer is overwhelmed, I see voltage sag on AC-In-1, e.g. instead of 240V I see 230V or less.  This is especially challenging because I have a second structure (workshop) which has a 'parasitic' feed from the house main panel which is 50 meters of 4 AWG aluminum wire, so there's significant voltage drop between the house and the workshop.  I've tried to combat this there by also installing a Quattro (in this case the 230V/15 kva model + autotransformer) put in power assist mode.

In both cases, the Quattros seem to 'assist' up to the voltage it sees on AC-In-1 instead of powering up to 'nominal' voltage without sag.  Is there a different way I could configure my Quattros so they provide 240V AC-Out-1 even when AC-In-1 is 230V or less?

Thanks in advance,

 - Jay

SumPower

Since the inverter syncs with the incoming voltage from the grid, when the voltage sags on the grid connection it will also sag from the inverter simultaneously. I don't see how you could get around this, except for disconnecting from the grid at peak load time. Probably not a good option unless you have plenty of battery storage.