Multiple Solar Panel Install

Rock-Rocker · 12-25-2007, 12:35 PM

My Wife gave me a nice surprise for Christmas two 50 Watt Solar Panels with all the trimmings. This is something we have been talking about for some time so I think she did pretty good on getting what I was thinking about. Now I will need a bit of advice on installing these. If anyone can help me out it would be greatly appreciated. She got me 60ft of 10 AWG wire, the Z brackets, fuse, 16 Amp controller and 2 Kycoera 50 Watt Panels. I have a 2006 Adventurer and I think I have a pretty good idea of where on the roof I want to mount the panels. I plan on running the wire down thru the fridge vent. I need a bit of advice on the wiring arrangement. Should I run the 10AWG wiring from one panel to the next (series) and is the 10AWG enough to run combined from there to the controller or will I need a different AWG of wire? Any recommendations, ideas, past experience etc, would be very much appreciated. I hope everyone had a Very Merry Christmas and to those back East enjoy the white Holidays.

Rock-Rocker · 12-25-2007, 12:35 PM

My Wife gave me a nice surprise for Christmas two 50 Watt Solar Panels with all the trimmings. This is something we have been talking about for some time so I think she did pretty good on getting what I was thinking about. Now I will need a bit of advice on installing these. If anyone can help me out it would be greatly appreciated. She got me 60ft of 10 AWG wire, the Z brackets, fuse, 16 Amp controller and 2 Kycoera 50 Watt Panels. I have a 2006 Adventurer and I think I have a pretty good idea of where on the roof I want to mount the panels. I plan on running the wire down thru the fridge vent. I need a bit of advice on the wiring arrangement. Should I run the 10AWG wiring from one panel to the next (series) and is the 10AWG enough to run combined from there to the controller or will I need a different AWG of wire? Any recommendations, ideas, past experience etc, would be very much appreciated. I hope everyone had a Very Merry Christmas and to those back East enjoy the white Holidays.

DavidMc · 12-25-2007, 02:30 PM

Generally you are thinking in 12-volts DC when working with small solar systems. Most likely the panels are 12-volt panels.

If they are configured for 12-volts, you will want to connect them in parallel.

The 10awg wire is sufficient for interconnecting them for the short distances between the panels on the roof.
Most people will recommend a junction box on the roof from which a much heavier wire (small numbers like 8 or 6) then carries the combined current to the charge controller. Plan ahead for possibly adding another pair of panels (which should still "fit" within the capabilities of your controller) - - user larger wire than 'required'.

Similarly, run large wire from the controller to the batteries.

Several people have extensive solar descriptions on their web sites. My site has a simplistic description (with some pictures) also.
There are numerous commercial solar vendors/installers with instructions on their web-sites that a Google search should find.
Using the Find features of this forum looking for the word 'solar' will also yield a lot of information.

Loren · 12-25-2007, 04:22 PM

Just want to add a little to what David said. The 10 gauge wire will be good enough for the panels you have. We have three 70 watt panels and they work fine with the 10 AWG wire, not to say that 8 guage wouldn't be better!

If I ever add more, or larger panels, I will have to do as David said; use 6 AWG from a box on the roof, as well as a larger controller, so not planning that soon

By-the-way, welcome to the forum

glad to have you aboard. You live in a nice area, we have friends that live up there; about a 2 to 3 hour drive from us.
Loren

bruceh · 12-26-2007, 08:23 AM

I wonder if we are getting a little carried away with wire sizes. I have 150 watts on my roof and on a good day will charge at about 9 amps. The theoretical max for this is about 12 amps. If you look at the amererican wire gauge table (http://www.powerstream.com/Wire_Size.htm), it shows that 10 gauge is more than adequate verging on serious overkill. For 100 watts, the margin is even greater.

I mention this because the wire gets pretty expensive and hard to work with as it gets bigger than 10 ga. Mine is wired with 12ga and works quite well.

DavidMc · 12-26-2007, 08:46 AM

Part of the question is distance between points in the system where the highest amperage is expected.

Some sample wire sizing tables (generally showing the maximum number of feet to run that size wire at a certain amperage load):

http://www.windsun.com/Hardware/Wire_Table.htm

http://www.aaasolar.com/ProdLit/Help...6-WIRESIZE.PDF

http://howto.altenergystore.com/Reference-Materials/How...for-Your-System/a62/

http://www.solar4power.com/solar-power-volt_drop.html

Yes there is additional cost, and sometimes more awkward working effort for larger size wires. The trade-off lies in the net energy able to get to the various parts of the system (after losses in the wire), and also in the question of needing to rewire should you up-size your panel array.

The calculator near the bottom of the ( www.powerstream.com/Wire_Size.htm ) page indicates the 12 volts at one end of a 30 foot run of #10 wire will only provide 11.26 volts at the other end, a loss of just over 6%.

Since R-R has 60 feet of wire - - if the run from the roof to the controller is short enough, he could use two-wires for each side ( 2 for positive, 2 for negative ) and recoup some of the costs already spent [and get close to a #8 wire conductance].

I am assuming that multi-strand wire is being used ( not the solid type used in housing). It is a little easier to manipulate.

Rock-Rocker · 12-26-2007, 05:07 PM

I would like to Thank Everyone for all their input. It has helped out out tremendously. Definately got me thinking again. Now I'm kind of thinking into the future and possibly considering adding a couple more panels later for a total of 200 watts. I feel this would be adequate for my needs. I guess I better use a junction box on the roof and run a heavier wire from there on down. Set the back end up now and I won't have to change it later. Hmmmm decisions decisions. I won't have to make any hastily decisions since the weather is dropping down into the low 20's and expecting snow Friday. Gives me time to do some planning and do it right.

Loren, it is nice here, Thank You.

Again, Thank You Everyone...

Richard S. · 12-27-2007, 05:10 AM

Rock-Rocker,
With cool weather setting in it will give you time to do your home work prior to instillation. There are many web sites about solar electric so you can be an expert in no time. Your off to a good start. You can also check out the panel manufactures links for support.

jimandsue60 · 12-27-2007, 05:48 PM

I have 4 100 watt panels from amsolar.com. I have 10 gauge wires from the panels going to a combiner box. I also have 10 gauge wire from the combiner box to the controller and batteries. Total length of @ 16 feet.

This afternnon I saw 21 amps going to the batteries (with the panels tilted). In the summer I see @23 amps.

We use alot of power for tv, internet and ice-making. We will typically run the genset for an hour or so to top things off in the evening. We do watch tv for 1- 3 hours in the evening.

The picture below is our roof top with our panels. There is one more panel that cannot be seen.

Jim