Distance between home and panels - Page 3

 

First, you must decide what voltage drop you're willing to tolerate.  Once you
determine that and you know the current output of your panels, you can figure the
maximum tolerable resistance using ohm's law.

Next find a wire resistance table - they're all over the net - that lists ohms
per
foot or ohms per 100 ft for various wire gauges.  Using the distance involved
times 2
(two wires), determine what gauge wire you must use to achieve your maximum
tolerable
resistance goal determined in the previous paragraph.  Then to accommodate
resistance
in connectors, fuse(s), switches, etc. that might be in the circuit, go to the
next
larger wire size.

As to cost, you can look at places like http://www.waytekwire.com  or any of the
big
box stores' websites.  Given the current price of copper, it's gonna be painful!
Clean #1 copper scrap is currently over $3/lb and is predicted to hit $3.60 by
Christmas.  It might be a good time to take a look at aluminum cable.  It'll be
physically much larger, as aluminum's conductivity is significantly less than
copper.
Aluminum is sufficiently cheaper than copper to make the larger cable less
costly.
Probably.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com  <-- best little blog on the net!
Tellico Plains, Occupied TN
I love cats ... they taste just like chicken.

  Good information--thank you. Also interesting about aluminum. Size isn't an
issue for me (that is, I won't care if the cable is thicker vs. thinner, as
no one will be seeing it other than me). So if resulting quality (amount of
power) will be the same with larger aluminum vs. smaller copper, I will
consider it.

 

Didn't we just have this same discussion, about a Remote Wind System,
a few months ago...... maybe Goggle needs to become your friend.....


Since you will need a Charge Controller, in your system, anyway, why not
use an MPPT Controller and raise the System Voltage at the Array to
something like 48Vdc, and then have the Controller do the conversion
down to your Battery Charging Voltage. MPPT Controller cost a bit more,
but since your going to invest in Inverter/Battery/Solar, you might as
well get the best BANG for the BUCK.

By increasing the Array Volatge, you mitigate the I2R losses in the
300Ft of wire for same power, transfered. More BANG for the BUCK.....
and Watt Transfered. OutBack makes really nice MPPT Controller, as do
some others in the industry.

Bruce in alaska
--
add <path> before @

 This is to be an add-in to an existing system, so no, I won't need a new
charge controller, batteries, and so on, so no, putting equipment up on the
mountain (other than the panels) is not an option.

 Tell us the brand and model of charge controller and the number of
panels, and we'll recommend a configuration that we think is optimal.
I guess if 3 people give the same suggestion, you can go with it.