Can I use a Hoymiles HMS-2000 as a backup Inverter

Hi I'm investigating if it is possible to use a HMS-2000 as a backup Inverter using OpenDTU as management system.

My plan is as follows, one of the 4 solar panels inputs of the HMS-2000 I make switchable between a 50V panel or a 48V LiFePo4 battery. The HMS-2000 will be configured for Zero Export. This means at night one of the solar inputs sees a 48V panel and when the house asks power it will come from this HMS-2000 who is using its battery of which he thinks it's a solar panel. As long the grid is available, I dont see no problems here.
When the grid has a blackout, the HMS-2000 goes to island mode and then no energy is coming from the HMS-2000 inverter. What I would like is to add a transfer switch to the installation that isolates the whole house from the grid and bypass this island mode protection function, so I can continue to use the Inverter function to generate electricity.

My question: is it possible to either bypass/switch off this island mode function, or to find and other trick to make use of the inverter during blackouts. This all given that I make use of a transfer switch to isolate the house from the grid.

Hope someone can tell me more about this.

Piet_de _Pad said:

bypass this island mode protection function.

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AFAIK, the micro-inverter still needs a grid supply for it to synchronize with. You need hybrid or off grid inverters that can form their own micro-grid to function once they are fully disconnected from local grid.

agarg said:

AFAIK, the micro-inverter still needs a grid supply for it to synchronize with. You need hybrid or off grid inverters that can form their own micro-grid to function once they are fully disconnected from local grid.

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Thanks agarg, I understand your remark. Do you think that I can add a small Sine Wave Inverter as a sync source to this micro grid and let the HMS-2000 do the bulk of the work. Or when I AC couple these two sources, one gets crazy and blows up the other.

This use case will have to be very seriously thought through. The grid presents an infinite sink of energy with very low impedance (resistance, inductance, and capacitance). The energy produced by micro is at a higher potential (voltage) so that the gradient allows for flow from high to low. The export management uses this voltage variation as one of the techniques. In a Zero export situation, when the domestic load changes, the micro will have to readjust its energy flow. For the fraction of that time, it will send that energy to the grid. So, is that sine-wave inverter able to absorb that energy or will it get toasted?

The off-grid systems are different. One can notice fluctuation of light, in some cases as it tries to readjust energy output. This is my limited understanding and I may be a bit wrong in this. Perhaps others can chime in....and educate!!