1-phase, 2-phase or 3-phase installation

[Markok]

I have a single-phase installation with one MultiPlus-II GX. This unit is a bit too small for my needs, so I’m planning to install one more MultiPlus-II and configure a two-phase system. Is this kind of installation acceptable in a location that uses a three-phase grid?

If I have a two-phase setup, what happens if second phase is lost? Can the system continue to operate on a single phase without reconfiguration, or will it go into a failure mode?

[TomBerger]

@Markok

I have a single-phase installation with one MultiPlus-II GX. This unit is a bit too small for my needs, so I’m planning to install one more MultiPlus-II and configure a two-phase system.

This depends on the laws in your country and if your local grid operator allows it.

Here in Germany, a maximum unbalanced load of 4600 W on one phase relative to the other phases is permitted. Feeding power into one, two, or all three phases is allowed, provided this unbalanced load limit is always observed.

[DirkW]

What kind of system did you have? Single phase ESS?

[Markok]

In Finland, an unbalanced load of up to 3600 W is allowed, and the MultiPlus-II 48/3000 is suitable for that.
Currently, I have it installed on a single phase, and the situation would be similar in a two-phase setup. I’m also using a single-phase ESS configuration.

Sometimes, when the grid fails, it would be nice to charge the batteries from a single-phase generator. My plan is to install a grid/generator changeover switch and set the inverter to “charger only” mode when I want to charge the batteries from the generator.

I believe this should work in a single-phase setup, but how would it behave in a two-phase installation?

[DirkW]

There is a large discussion in the German part how to use a generator at a ESS System…it is not so easy….

The question about generator backup is asked 1-2 times a week

Batterie von ESS-System über Multiplus II mit Inverter-Stromgenerator laden

Das Hausnetz ist dreiphasig. Weil nur ein MP 2 3000 installiert ist, wird bei Stromausfall nur eine einphasige Versorgung geboten. Das ist aber nicht weiter schlimm. Es sollen ja nur wichtige Verbraucher (Kühl- Gefrierschrank, Heizung, Licht, …) funktionieren. Das schafft der kleine MP 2 auch und über eine Nullleiter-Verstärkung vom E-Herd brauche ich mir bei der kleinen Leistung auch keine Gedanken machen. Ich bleibe gespannt, ob und wie die Akkuaufladung klappen wird.

Adding a second Quattro (charger-only) to increase overnight charge rate — ESS, single-phase

Hi Bjorn. Thanks for that. I am in fact running an eltek at the moment. I do get a bit concerned by the temperature of the card in the back. It’s around 60+ °c when going for it. So I have it throttle back a bit to 1.3. It’s also running from a plug at the moment which is another reason to have it powered down.

[kwindrem (Kevin Windrem)]

I think this will work.

You’d configure the system with 120 degrees between the two Multis and for the charger to function with only one phase powered, you need to turn off “switch as a group”. The Multi receiving generator power would charge the battery bank while the other would CONSUME power to feed it’s loads.