Splitting one panel to two inputs of a micro-inverter, what happens?

[meetyg]

Hi.
I have a no-name MPPT micro inverter that is suppose to handle up to 600w.
But, it has 2 inputs and each is limited to 300w by the specs.

I have a 455w panel, which is too much for a single input.

I can confirm that actual open voltage is around 45v and open circuit current is at or above 10a (it actually blew my multimeter's 10a fuse). So it's really putting out that wattage.

I thought of splitting the output of the panel into two branches (using a Y connector, but backwards) and then connect each branch to to each of the micro-inverter's inputs.

In theory that should split the wattage into two, but my question is does the voltage get split into two or does the amperage?

This is important because the inverter has a minimum of around 20v for it to start working. If a bit less sunny, or a bit shaded (or hot) I guess the panel voltage could drop even below 40v, which would make the inverter refusing to start MPPT tracking.

Thanks in advance.

 

[snoobler]

Since you're splicing outside the panel, the voltage is the same. However, you're exposing both inputs to a potential of 455W, and you're trusting that they will always be in sufficient sync with one another that one side never has the potential to pull more than 300W.

It's possible the unit will only pull 300W from whatever the source is, so "over-paneling" the input might not be a big deal aside from the lost power.

If I was in your position, I would not pursue this course of action.

 

[meetyg]

Since you're splicing outside the panel, the voltage is the same. However, you're exposing both inputs to a potential of 455W, and you're trusting that they will always be in sufficient sync with one another that one side never has the potential to pull more than 300W.

It's possible the unit will only pull 300W from whatever the source is, so "over-paneling" the input might not be a big deal aside from the lost power.

If I was in your position, I would not pursue this course of action.

I guess they have a reason for specifying a maximum wattage for each input.
I'm afraid to try and connect the panel to just one input (don't want to fry it).

 

[TomC4306]

Then don't.

 

[pollenface]

You can connect micro inverters to batteries which have bulk wattage/current available and it doesn't fry them. The inverter controls the panel, not the other way around so long as you stay within the input voltage specs, the Isc and max wattage are virtually redundant. The inverter only takes what it needs to produce it's rated output (with some efficiency losses) --- kinda like a light bulb.

 

[meetyg]

Thanks.
But it's still interesting why they specify max wattage for each input of the microinverter.
These microinverters seems to have a built in fuse, so maybe they require a max wattage that will be under that fuses amperage.

 

[pollenface]

I call it Monopoly.

In Australia, 132% was an arbitrary figure which made it's way into the "Clean Energy Council" guidelines and then grid-tied inverters were then specced accordingly.