Mppt voltage vs current

I have a 7000 watt mppt inverter. I want to find the optimal size of the string.

Does mppt like more voltage or current from pv panels?
What is better 300V 20amps or 450V 15.5 amps. Or this is completely irrelevant and inverter will work hard no matter what? I've noticed the inverter fan run full speed when charging but when taking load from solar after the battery is full it doesn't heat up so much

You must be under the Voc limit with enough margin to ensure the panel voltage doesn't exceed it in winter, and you can't exceed the PV input current limit. You typically need to max out current and go as high as you safely can on Voltage to get anywhere near max rated power.

Solarguy said:

I have a 7000 watt mppt inverter. I want to find the optimal size of the string. Does mppt like more voltage or current from pv panels?

Click to expand...

Solarguy said:

What is better 300V 20amps or 450V 15.5 amps. Or this is completely irrelevant and inverter will work hard no matter what?

Click to expand...

I think there is a slight difference in efficiency but it likely varies from inverter to inverter. For instance if AIO has both a 300VDC rail to directly power the inverter and a charger that runs off this, then one might think having the MPP close to that point would be better.

Solarguy said:

I've noticed the inverter fan run full speed when charging but when taking load from solar after the battery is full it doesn't heat up so much

Click to expand...

Is it actually moving the same power when the battery is full? You would need need either dump load or grid export to do this.

If there are no loads then the power coming down from the solar panels will drop. And the balance is burned up as heat within the solar panel.