Pass through current for an inverter

[Tradie]

Another misunderstood topic.

What is pass through current for an inverter?

Can the grid terminals handles the 50 amp pass though current?

Can the aux terminals handle the pass through?

Can the load terminals handle the pass through current?

If the load terminals can handle the 50 amp pass through current, then why is the inverter load rated to 34.8 amps?

[Tradie]

My understanding is that the grid terminals are rated at 50 amps (pass though) to handle the 34.8 amps of the load and part of the current to charge the batteries or the current required to feedback the power from the solar while the grid is on.

The load terminals are only rated for 34.8 amps, not pass thorough current, but hey I might be way off track, feel free to put the record straight.

I can't tell you the aux terminal ratings are, but I am sure there are way smarter people with a better understanding who could se the record straight.

I had a discussion with an engineer yesterday and some of the things he mentioned that he had read on some of the groups (I dont waste my time following anymore), got me started with these threads this morning.

It is scary to see how confused people are when it comes to solar, and the lack of clear credible data being shared.

[Justloadit]

The 34.8A is the rating of the electronics in the inverter - 8kW
Whilst theoretically the pass through current is higher, the inverter sees this as overload, as in a case of power fail, the inverter needs to maintain the load supplied, exceeding its rating, and the inverter will trip on AC overload current.

[Tradie]

Would we be correct in stating that all the contactors are rated for 50 amps grid/aux/load, and all connected to a common busbar, that under normal operation conditions, you can push 50 amp (the absolute limit) through any of the 3 terminals. IF so then why were so many so many Sunsynk inverters returned for warranty claims top replace the contactor on the inverter output ?

The question we should be asking, what is pass through current and were will this pass through current flow, on the inverter input terminals, to carry the output load and for charging the battery? the AUX terminals and the output terminals ? This I believe is what is causing all the confusion. Until this is cleared up and everyone understands pass through current, we going find entire DB connected to a 5 or 8 kw inverter.

Would I be correct in saying that if the grid is switched on then it is power in through the input contactor onto the common busbar (rated at 50 amps) and out on the inverter output terminals also rated at 50 amps ?

However when the inverter is in islanding mode, it is only capable of handling 34. 8 amps, if you a 50 amp mcb on the inverter output terminal, eventually something is going to pop.

Something else I have identified, the bypass switch in the AC control has a challenge which I dont think many people are of. IF you dont fit the 32 amp mcb after the bypass switch, you will have to install it at the Sub Db to protect the wires when in bypass mode. If you have a 50 amp on the inverter input and 63 amp bypass switch with 10 or 16 mm sq wires, then what will happen is the cable on the output of the bypass switch will be under rated when the inverter is bypassed.

The 34.8A is the rating of the electronics in the inverter - 8kW
Whilst theoretically the pass through current is higher, the inverter sees this as overload, as in a case of power fail, the inverter needs to maintain the load supplied, exceeding its rating, and the inverter will trip on AC overload current.