Series vs parallel efficiency questions

[Electric City]

Hello all,

I just got a classic 150 and am really excited to get it set up, but I've got a question about series vs parallel efficiency. I tried searching around, but didn't have much luck.

I'm under the impression that an mppt is less efficient at higher voltages, is that correct? Or is it just that the higher voltage classics (200-250) are less efficient than their lower voltage brother?

Anyway
3x 250w 24v panels.  Voc 37.5v,  Isc 8.87a, Vmp 30.1v, Imp 8.32a
20-25 feet (40-50 round trip) run of 8 gauge wire
12v fla battery bank (4x T105re 6v batteries at 225ah each)

Which would likely be more efficient :

Panels in parallel combined at the panels - higher current over 40-50 foot run, resulting in current drop, but higher efficiency in the mppt.
Or
Panels in series, resulting in less current drop in the wires, but less efficiency in the mppt?

Thanks in advance.
Sam

[Cniemand]

Higher voltage from the array to the charge controller to keep line loss to a minimum. Then let the CC do its work. I went with the Classic because it came in a 200v version where you could string 4 panels in series and then the two strings in parallel for 150v @ 16-18amp coming in. (2000 watts)

My line loss that way over a 30 ft run with 10 gauge wire is less than a half percent.

[Cniemand]

Are you using a 12 volt inverter? Or direct 12vdc loads? Otherwise you could reconfigure your bank to be more efficient at 24v while still using the same Classic.

[Electric City]

Thanks!
I was thinking that series would probably be better, but I just wasn't sure.
And yeah, 12v is my only option, I'd love to run 24, but I have a couple 12v loads.

Also, unrelated, the security question to make an account (what was last year) is still set up as if it's 2015. Not sure who to tell that to!

[CDN-VT]

Series If you figure this out !!
Add your number is  & it will answer your question :
http://www.midnitesolar.com/sizingTool/displaySizing.php

And USE a 24Vdc to 12Vdc PWM unit 720 watt down to 80 watt units are great !!