Portable panels wire size

AStinker- wrote:

BFL13 wrote:
This calculator us useful in that

A. it counts going both ways so you don't have to wonder if you need to double the distance.

B. You can try different gauges and see what you get for voltage drop.

What it does not do is tell you what amps you will get with what voltage drop. We had a thread about all that where that got answered using watts (so of course I got confused :) )

Just fill in your own numbers instead of whatever is there now

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=2.061&voltage=12&phase=dc&noofconductor=1&distance=60&distanceunit=feet&eres=8&x=42&y=5

In my case it revealed how with 24v panels and 12v battery, you need to do the panel to controller at 24 and the controller to battery at 12. With 12v panels you do both at 12

Ok thanks again BFL
I hope you haven't already answered this but in the calculator do I enter the Voc or Vmp of my panels?

And for Load current do I use Isc or Imp of my panels?

Musn't say "load" here. Might get mixed up with controller "load" terminals.

Use the total Isc of the panels for expected current from the array. Use battery voltage for what is on the wires when using 12v panels. On solar that will be about 13 in the morning to about 14.5 later on.

If using 24v panels, then use Vmp for the voltage on the wires from panel to MPPT controller and Imp for the amps. Then from the MPPT controller to battery use battery voltage but now "expected amps" is way higher than panel Isc (not used by MPPT) However as a rough guide, IMO just use double the panel Isc as what you might see. Gives you a good enough idea for picking the wire gauge. What amps you actually get will depend on all that MPPT magic stuff to do with watts and AFAIK, your horoscope for that day. :)