Solar panels wire to controller: Length of wire?

OregonTRX4 wrote:
I have 50 feet of 10 gauge wire on the way. So my understanding is that I can wire the panels about 40ft from panels to controller and then my controller will be 1.5 maybe 2 feet to the batteries. Should this be okay with minimal voltage loss?

The wire between the controller and batteries should be 2 gauge, may possibly get by with 4 gauge.

OregonTRX4 wrote:
I have 50 feet of 10 gauge wire on the way. So my understanding is that I can wire the panels about 40ft from panels to controller and then my controller will be 1.5 maybe 2 feet to the batteries. Should this be okay with minimal voltage loss?

You count for both pos and neg for voltage drop so if your panel is 50 ft away you need 100 ft of wire, 50 each. The voltage drop calculator should make that clear.

This one is clear that the "distance" is using the double amount (for a single SET of conductors), so there is no confusion

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

How much is "ok" and "minimal" is situational and personal up to you. I would be ok with it in my own case. It is better than getting zero by not being able to get the panel out into the sun.

I have 50 feet of 10 gauge wire on the way. So my understanding is that I can wire the panels about 40ft from panels to controller and then my controller will be 1.5 maybe 2 feet to the batteries. Should this be okay with minimal voltage loss?

PWM
I'm sticking with the theory that the panel is directly connected the battery during bulk of 13.5v and the controller doesn't limit voltage till Vabs. Volt drop (controller-panel)may be a concern under those conditions but the current should taper till it is no longer a big deal. .08v @ 14.6, 4' 10 awg.

Full, the controller would limit to float with low current.

Ed is right about cable to the battery. When using a controller without a separate voltage sense wire - a feature usually not available in cheaper controllers - your cable to the battery should better be short and beefy. Otherwise the voltage drop will cause permanent under-voltage on the battery terminals.

Controller without voltage sense wire will assume that its output voltage is delivered nicely without losses all the way to the battery, which is of course not the case. For example, when controller output is 13.5V @10A, a 4ft double cable #10 will cause the 13.5V output to drop to 13.3V on the battery terminals. Which means, your batteries will never be properly charged. Get #4 cable if you can, a big 50ft roll will still cost less than a new battery.

But, if all this is only for floating full batteries at 1A, then the same 2*4ft wire #10 will cause less than 0.05V drop, and this won't affect the floating.

OregonTRX4 wrote:

How long can I run wire from the controller to the panels before it impacts performance beyond a reasonable level?

Even with PWM controllers, the voltage drop from Panels to Controller is typically not significant during conditions with lots of sunshine. What is very significant is the voltage drop between the Controller and Battery - that voltage drop must be kept to a minimum with short fat wires.

The PWM controller will reduce the voltage to 14V or 15V (on both sides of the controller) when batteries are getting charged. But the panel is trying to put out 18V or 20V. So losing even a huge 2 Volts between the panels and controller won't be that significant.

Ed

That would be a good choice if there's some UV protection and water resistance

Some people said they have been using 10/2 landscape wire. Any input on that?

BFL13 wrote:
The OP has two 160w panels and a PWM controller.

He said in the 1st post: 2 80W panels.

I used this stuff for my portable system GenuineDealZ. They build some nice custom cables for a good price.