Can I run these panels in 2s?

[1201]

Panels have a vmp of 30.8(voc 37)

Inverter has a minimum voltage of 60v

Will two of these in series with a nominal voltage of 61.6v start the mppt or is this too close to the minimum?

I can run 3s but it would be less convenient

 

[diymarek]

have you checked if you panels can actually do 30.8V in your geography throughout the whole day?

 

[1201]

have you checked if you panels can actually do 30.8V in your geography throughout the whole day?

Good point-i haven't

 

[diymarek]

cross check that with the min and max mppt voltage supported by your controller and the decision will be simple...
my current panels have Vmp 42.35, and I rarely see them going above 31.8, so 8S as opposed to 4S/2P or anything alternative was a no-brainer for me... (especially that my inverter's operating range is 120~450VDC)

 

[timselectric]

Too close.
It might work, sometimes. But probably not, most of the time.

 

[1201]

cross check that with the min and max mppt voltage supported by your controller and the decision will be simple...
my current panels have Vmp 42.35, and I rarely see them going above 31.8, so 8S as opposed to 4S/2P or anything alternative was a no-brainer for me... (especially that my inverter's operating range is 120~450VDC)

Yeah it looks like I have to go 3s. 2s is too low and 4x is too high.

Too close.
It might work, sometimes. But probably not, most of the time.

I think you're absolutely right

 

[Doggydogworld]

Yeah, I agree you need 3S. Voc and Vmp decrease when the panels are hot. Let's say your MPPT increases impedance to keep hot panel 2S string voltage above 60V instead of just shutting the string down. And say hot temps drive actual Vmp down to 54V. Your output at 60V in those temperatures will be far less than at 54V, maybe as much as 50% less. So even if it "works", it won't work well.

 

[MichaelK]

It would be best to actually post the brand/model of your panels, and also the brand/model of your inverter. Keep in mind the temperature coefficient of your panels. Usually we are admonishing people here that panel voltage goes up as the temperature goes down. The reverse is also true. The voltage goes down as the temperature goes up. It seems likely that the panel string could go below critical voltage on a very hot summer day, perhaps with charging shutting off because of it?