question

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stgnet asked

Split phase feeding power to grid

Trying to replace a dead Schneider with a Victron system. Current wiring has AC IN and AC OUT of the dead inverter connected through a set of 60a breakers into the 200a residential panel (split phase 120/230) and it was set up to feed power to the grid in addition to taking some of the local load. Power source is 48v battery with dc coupled solar charging (non-victron). I understand I can use an autotransformer to convert a single 120vac or 230vac inverter into split 120/230 L1/N/L2 as needed to connect to the existing breakers/wiring. But I need to confirm a) that Victron inverters can be used to feed power to the grid (nothing to do with grid-tie from solar on AC OUT), b) what the wiring should be for this -- i.e. use the same set of breakers that connect AC IN & OUT, or do I only need to connect the multiplus/quattro AC IN to the grid and done.

So in essence, does the multiplus or quattro inverters have the ability to feed power synchronously to a grid over the AC IN connection -- will it work if I feed the inverter 48v DC and have it generate power to the grid over the AC IN connection only, or does AC OUT have to be tied to the grid in some way (which seems dangerous, and not sure why the Schneider was wired that way).

I understand that I will need to set up the inverter with ESS helpers for it to successfully feed power to the grid and take up some of the local load without having a 100a subpanel to run the loads through (I'm not going to rewire his panel). I'm just needing confirmation on selecting the correct inverter, and how to wire it, and confirmation that this is even possible. I'm preferring to use a single inverter and autotransformer rather than two inverter across the split due to cost, but if there are reasons to avoid the autotransformer for this situation let me know.

gridsplit phase
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1 Answer
silverfox avatar image
silverfox answered ·

I have a similar ESS situation. I want to replace our aging Trace Dual stacked SW4048s (predecessor to the Schneider) with 2 Victron Quattro 48/5000 120 volt units wired 120/240 split phase. Too many limitations with 1 unit and autotransformer.

I came across this helpful diagram from Victron (but I don't know how it got posted) -

https://www.victronenergy.com/upload/documents/Split-Phase-Quattro-system-with-Cerbo-GX-Touch-50-Discover-42-48-6650-Smart-solar-MPPT's.pdf

I have my own (not Victron) battery and 2 Outback charge controllers for our roof solar panels, and also have a PV Inverter which would go on the AC Output side, with a Victron AC Current Sensor for monitoring by the Cerbo GX. My dealer says all this is possible, but I'll need a dongle (maybe Interface MK3-USB Configuration Tool?) to program the Quattro's, and a Victron SmartShunt for the Cerbo to monitor the battery.

According to everything I can find out so far, this is all quite possible. But I have not yet found out, other than the above diagram, just exactly how to do this, nor found just what programming is needed other than simply selecting 'split phase' in the configuration menu.

It would be very helpful here if anyone else who has done this could please chime in with your experiences, tips and suggestions! So much of what I see in this forum is RV and boat. Of course, there is much that is the same for residential, fixed-in-place setups like mine (and yours, stgnet?) but there may also be some significant differences - grounding in particular.

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