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colj avatar image
colj asked

Using ESS off grid without a generator but with Solar PV

Hi All,

I've seen the ESS manual where it says not to use offgrid/intentional islanding but not sure I fully understand why. My use case is :

  • ESS system with Quattro (sized to handle all house loads), batteries sized to run house loads for >24 hours.
  • On a cheap rate tariff (6 hours overnight) - plenty of time to fully charge batteries - uses ESS scheduled charging.
  • System also has Solar PV and I have an automation to estimate to what SoC batteries need to be charged overnight so that they shouldn't reach 100% during the following day. Uses ESS settings to control overnight charging level.
  • No generator
  • I want to run on-grid for the scheduled charge window, then off-grid during the day until the next scheduled charging window. Thus I can guarantee that when the inverter is running it is not connected to the grid (and absolutely guarantee that there is zero feed-in to the Grid).

I could just physically cut the AC1 IN via the isolator but I don't want to get up at silly-o-clock! From what I read elsewhere this might be possible using a flag and generator options but comments mostly seem to say don't since it it's not a supported combination with ESS.

Appreciate any comments/thoughts?

Colin

ESSoffgrid
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shaneyake avatar image
shaneyake answered ·

You can do what you want and still use ESS.
This is a non standard use of ESS which is why it isn't officially recommended but will work fine.

Here is a guide to disconnect the inverter from grid using the AUX1 input on the inverter.
You can then use the generator menu on the GX to control the relay on the GX. You then wire the relay output to the AUX1 input on the inverter and then whenever you start "generator" it will connect to grid and when you stop "generator" it will disconnect from grid.
https://shaneyake.blogspot.com/2022/09/victron-disconnect-inverter-from-grid.html

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colj avatar image colj commented ·
Thanks for the link - my existing automation is in node-red so that's an easy addition to have charge window based timed functions that set the switch position!
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