Solar controller to battery distance?

Muddydogs wrote:
The controller I am looking at states 7 ga is all the terminals will handle. I would really like to use 4 ga as I already have about 20 feet laying around from a boat wiring job.

Yup, good choice. I used 4 AWG for all of my installation. I used these type of 4 gauge spade terminations to connect to the controller.

#8 is fine. It not like you have 30 amps here.

smkettner wrote:
6' is fine. Use max wire the terminals accept.

You are allowed to use the max terminal size wire as short pigtails to join with fatter wire for the long run. You can also shave some strands from the fat wire till it fits in the terminal (set-screw type) There are even step down wire lug terminals you can buy that can then fit in the controller terminals.

The controller I am looking at states 7 ga is all the terminals will handle. I would really like to use 4 ga as I already have about 20 feet laying around from a boat wiring job.

Distance between, as stated, should be minimized. What this really means is that voltage drop needs to be kept at no more than 2% and lower than that if at all possible. If you run into cable sizes getting too big for available terminals, start thinking of multiple cable runs, or multiple terminals on the same stud. Another way to do it is to split the cable strands in half and connecting each separately.

As far as cable protection, be sure to use the split loom that's available in various sizes from a local hardware stores, electrical supply houses and big box stores such as Lowes or even NAPA's and auto supply stores. Clamp in place tightly and often (close together) and you'll be fine.

Answer, as close as possible.
Any farther than that, need to know the amps (about 5a per each 100 watts)
If only 10-15 amps, I'd think 10ga big enuff. But 8-6 ga can't hurt.
My 20 amp controller will only handle 10 ga.
But I have never let a little voltage drop ruin my day either :)

You can mount it as far away as you want. You just have to run larger wire the farther you go. Try to keep the voltage drop to no more than 2%. There are online calculators to help you figure that out.

6' is fine. Use max wire the terminals accept.

No. Use 6 guage wire and you will be fine.

NO. JMO