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Is it possible to connect an ATS into "AC In" on the Multiplus II that switches to genset when there is a power outage and have the GX device know that it can not export any power as it has changed to Genset instead of Grid?
Or is there a better way of having Gen backup on a grid connected ESS system?
AC input types are basically static (Input 1 should either always be a generator or always be a grid). The best way to do this wouldbe to use a Quattro as it designed for two AC inputs and use with both grid and generator.
You can get away with this in a MP II but will probably end up having to do the changes manually every time you swictch from grid to gen (not ideal).
Good question Ross. Theoretically the MPII should see the gen output as grid (after the initial grid fail depending on ATS delay) and sync accordingly, then keep doing whatever ESS it’s setup to do. But in reality it depends on the generator. If it’s a high end full inverter 9kVA Full Sine Wave then all would be normal. But… if it’s a cheap Chinese Industrial grade genset, then it’s output would be a dirty square wave that swings between 48-52 hertz with voltage bouncing around. This output would rejected by the MPII as “week AC” and treated as a continued failed grid / LOM event and the MPII would just remain in anti-island mode. The only way around this is to disable "LOM" detection in the Grid Code VE_Config. Type "B" LOM Detection should still work fine with a decent stable generator. The perfect solution is to install a Quattro and therefore have a dedicated Generator AC Input AND a Grid AC Input.....
I have written an enhancement for adding an automatic transfer switch ahead of a Multi:
https://github.com/kwindrem/ExtTransferSwitch
This uses a digital input to tell the GX device if the incoming power is grid/shore or generator. The GX device then changes the input type from grid/shore to generator and sets the AC input current limit to appropriate values.
I can not speak to what happens with ESS feed-in when on generator. Does an input type of Generator disable feed-in? If not, additional work would be needed in ExtTtransferSwitch and I'd need help from someone who understands ESS to make sure power is not fed back to the generator.
Hola. Yo necesito algo así y no encuentro solución. Pero tengo otra duda… ¿sería posible conectar un generador en AC OUT 1? Sería algo similar a lo que propone Victron en este esquema, pero sumando un generador
The Multi and Quattro AC inputs disconnect from the inverter/charger core via a relay similar to the one on the AC output but the logic to control the input relays is completely different. The Multi/Quattro has circuitry that monitors the AC input(s) for voltage and frequency with the relay open. The inverter/charger core then attempts to synchronize to the selected input (AC 1 priority in a Quattro). Only after the synchronization is successful does the relay close.
The AC 2 output has no voltage and frequency monitoring so it is not possible for the inveter/charger to synchronize to it before closing the relay. Closing the AC 2 output relay would then connect out of phase, frequency and voltage sources together (inverter/charger core and generator). Extremely high currents would flow and certain damage to the Multi and generator would result.
