12v or 24v

[DrIns]

Curious why you are concerned about startup voltage? Unless you plan to run them all in series in one string at higher voltage, which I wouldn't recommend. Shade on just part of any one panel will shut down the whole string. I have 2 parallel strings of 2 in series. One pair at the front of the van and one pair at the rear. If one is shaded, the other pair still works.

I have Renogy 160D-SS panels, 160W each, Voc is 22.9V. Total Voc for my setup is 45.8V

 

[rmaddy]

Shade on just part of any one panel will shut down the whole string.

This is only true if none of the panels have bypass diodes. Most panels have bypass diodes (including your 160D-SS) so series strings with such panels don't suffer nearly as much due to partial shade as series strings of panels without bypass diodes.

Though it may still be better to use a combination of parallel and series in some circumstances.