long wire runs with solar panels

[quidnon]

Hi All!

Newbie here - great forum and very good advice!

Here's the deal - put together an inexpensive 12V 80W array I scrounged together with spare parts and panels from various places: 4 (15W) panels from Northern and a used, single (20 W) BP Solarex panel, got them all for less than $300.  Using a 7A "solar force" charge controller feeding a bank of 2 ~100AH marine deep cycle batteries.  Splurged and bought a new Trimetric 2020 meter monitior.  System works well for my off grid extremely isolated mountain shack running the self composting toiled fans (~0.6A) asnd several 12 lights, fans.

Now the question...

To get any sun, I needed to place the array ~100-150ft away from the shack.  I ran #10 UF cable from the array to the controller.  I'm aware that this is likley outside the "acceptable" limit for voltage drop - I'm estimating that at best, I've getting no more than 4-5A from the array. Rather than go to a larger guage wire (can't afford it now), would it be possible to "double up" the #10 wire to get an acceptable voltage drop?  If so, how could I estimate my "effective wire gauge"?

Thanks for all the help and suggestions!

Best

Wayne

[kurt]

rule of thumb is when you double up on wire it is tha same as going 3 wire gages larger so 2 #10 would be equivelent to 1 #7 wire  you can check an online wire drop calculator to see if that would get you acceptable loss.

[kurt]

voltege drop calculator http://nooutage.com/vdrop.htm

[tecker]

The Northern 15 watt max out at around 20 volts. They say 1 amp but I think about 800 mill is the best they will do . You could get the amp from each on a really clear day

but Your  doing well with 4 to 5 amps . The best use for the Amorphous panels is to set up a pulser as they'll bring  20,000 Uf of capacitance up to 15 to 17 volts every sec on a good day and on a poor day they will still do a fair job bringing your batteries up . String the caps at about 5000 uf  every   20 feet and use the wire resistance to accent the pulser . I stuck with Jerry's one sec dumper for a year now and I got 7 northern 15 watt panels in tow . I use a 1/2 ohm coil in series and it rings a little  and chocks down the end rush for the transistors  the 100 feet of awg 10 is  around .1 ohm or less , Might ring a little .Anyhow here's jerry's circuit . You can nix the optocouplers and super glue a  opto transistor to the leds (rat shack Part # 276-145).All the parts are at "old ladyo slap" also (2n3055s for transistors) . The first stage is not necessary for supplies less than 18 volts at 5 amps but you'll need some good sinks and one ,more transistor on the dump stage . If this doesn't fit you curve you might start scrounging car batteries reconfigure for 24 volts and place the junk batteries at half way  putting an after dark timer to run a while ( depending on the way the junkers load test )  after sundown this will take care of most of the voltage drop during the day and give an early evening boost to the bank .

 

[tecker]

bombed out on the pdf load should have linked it try again.

  http://www.otherpower.com/images/scimages/1431/jerrys_chg.pdf