question

sesshoumaru avatar image
sesshoumaru asked

Restart in Island Mode with low battery and AC coupled PV

Assume the following:
Over night the power is drawn from the batteries, coupled with the inverters, to a point were it reached the low level of the battery, hence the inverts stop working - power goes out. The PV inverter is AC-coupled.


How is this system supposed to restart as soon as the sun has sufficiently risen?

The AC-out has no island grid up, so the PV inverter will not input power. The GX does not know that the PV inverter could provide enough power to load the battery and power the load (and its not terrible reliable I guess).


My working assumption is that I have to manually restart the vicron system once I am aware that the sun is reliable enough to keep the system up, but as the power from the grid is not availale and the battery is on low (e.g. 5%) - will this even work? Or is this the case were you either need a gen-set or at least some DC-coupled PV panels with MPPT?

MultiPlus Quattro Inverter ChargerESS
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3 Answers
Alexandra avatar image
Alexandra answered ·

@Sesshoumaru

Usually we have at least one dc coupled mppt to help with self recovering or a black start on a system. Once the system reaches the dc restart voltage everyhring will power back up. If the gx is on that is a good sign it means the system shut down before the bms disabled everything.

You can have an autostart on a generator as well but sometimes there are issue and that does not work. Like when a person onsite switches it on manually and forget to turn it back to auto or remote start.

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porcini avatar image
porcini answered ·

is this the case were you either need a gen-set or at least some DC-coupled PV panels with MPPT?

Yes, it is. If you have a string of solar panels which fits to the battery voltage you can temporary connect them directly.

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sesshoumaru avatar image
sesshoumaru answered ·

@Alexandra , @Porcini

Thanks for the information. I have currently already a generator in my setup, but I will check out the possiblity to add some DC-coupled solar MPPT as well.

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Alexandra avatar image Alexandra ♦ commented ·

@Sesshoumaru

Other thing to note if you have a Quattro it does not recover from black start on ac2 in.

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sesshoumaru avatar image sesshoumaru Alexandra ♦ commented ·
What do you mean by that?

I will have AC-in-1 connected to the grid (lets say its down) and AC-in-2 to the Genset.

I would assume it makes no difference if AC power is provided to either input to have the inverter comming up (yes, it will be Quattro II).

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Alexandra avatar image Alexandra ♦ sesshoumaru commented ·
@Sesshoumaru

I have not used the Quattro II yet.

But on Quattros we have installed if the battery is totally discharged and the invterter has shut down, the inverter will not restart even if the generator is running and connecting in on AC2.

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sesshoumaru avatar image sesshoumaru Alexandra ♦ commented ·
Wow.. that would be an unexpectdd flaw.

One should probably not discharge the battery to such a low level, but still... maybe a knowledgable Victron guy or gal reads this and could confirn or deny.

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