Hi, I recently got 9x395W panels for a total of 3555Wp of solar installed on my roof. This was combined with a dual mppt inverter (Growatt MIN3600 TL-XE). Watching the production data of the inverter I know the panels were put on string 2 since only this one was producing at around 1600W. While the other string always was around 2W, which I interpret as measurement error.

After seeing this I began wondering. Did the production top off at around 1600W simply because of how bright the sun was shining? Or was it due to the inverters maximum power output on that string. The spec sheet says it has a max. output power of 3600W. Does this mean you have to split your production on each string evenly (1800/1800) Or does this not matter and can you spread your panels how you want? (taking the required min. and max. voltages into account)

Second question: if you only use 1 string and your inverter dies, is there a possibility your other string still works?

Also even if the maximum power output isn't 1800W per string, would it still be better to make use of both mppt's instead of only one? (shadowing losses, inverter's life expectancy...) Or is using 1 string recommended to make sure your inverter turns on faster when the sun isn't that bright?

 

Thanks for taking the time to read my question. Greetings from Europe.

Well, if you have 9 panels, I guess there are 4 in one string (1580wp) and 5 in the other (1975wp). 

One MPPT input is managing the 4-panel string and the other MPPT input is managing the 5-panel string.

Regarding the second question, if your inverter dies, bad thing. No power at all.

The strings must be designed based on the MPPT operating voltage range. You cannot just put all pannels in paralel or series randomly.

There seems to be a problem with MPPT1 if the panels on it produced only 2W. Normally one will split them 4 and 5 as assumed in the previous post.