2 simultaneous MPPT connected to panel?

[macheung]

What happens when multiple MPPT chargers are connected to panel in parallel? Will they fight and fail catastrophically? Or will they just end up both working ineffectively?

I am planning a setup where I have a grid tie solaredge inverter, but also want to have some off grid capability. The solaredge inverter requires the use of optimizer, which shut down when the grid is out. I hope to use some y connector to connect a few panels to a off-grid inverter/battery bank. This off grid inverter would normally be disconnected and only hooked up to PV when grid is off. However, when grid comes back on, it is likely that the solaredge optimizer will turn back on before I can disconnect this inverter. Leading to a situation where there are 2 MPPT device connected to the panels at the same time. I don’t need them to work well in that configuration, just need to make sure they don’t fail in a bad way before I disconnect one of them.

 

[Short_Shot]

But why though?

I don't understand the situation that would require you to disconnect the panels.

It sounds like the system is just improperly designed.

 

[macheung]

The panels are always connected to the solaredge optimizer. The problem is that the optimizer work only with the solaredge inverter which shuts down the optimizer when grid is out. That is why I want to connect my off grid inverter charger to the panels with a Y “before” the optimizer. In this way, both the solaredge optimizer and the off grid charger is connected to the PV.

I am not sure what the behaviour would be like when both MPPT are active, so I only plan to connect the off grid charger/inverter when grid is down.

Does that make sense?