# The first real step



## Roadking (Oct 8, 2009)

Okay, I've played with the idea of solar for about 8 years; built solar space heaters, solar greenhouse areas in the house, etc, and have messed with little 1.5 watt solar battery maintainers...always wanting to go further, but cautious.

I just stepped up a bit. After a lot of research, came across this...

http://www.amazon.com/Complete-Sola...4226021&sr=1-18&keywords=100+watt+solar+panel

"100W Polycrystalline UL Listed: Solar Panel Charge Controller MC4 Connector Mounting Z brackets for 12V Solar Kit"
â¢1) Renogy 100 Watt Polycrystalline Solar Panel
â¢2) 10 Amp Charge Controller
â¢3) 10' extension solar PV cable. You can buy additional extension cables for your needs.
â¢4) Universal Z brackets to mount the solar panels on the flat surface

I thought abot the little 45 watt system from harbor freight, and was going to get one to play with, but have heard enough negatives here and other places that I started to really look around...best deal, with coupons from harbor was about $4 per watt.

This is not meant to be an energy independent item, it's for minimal use, emergency use, etc...kind of like a little backup plan for the next Sandy (ability to charge 2 trojan 115s for computer, cell phones, a couple of lights or the tv/vcr...have a 5500 and 4500 watt genny for the big stuff), but can also add on to it slowly as time and finances permit.

We are at about 41 degrees north, our south facing roof is at 42.5 degrees, close enough to do a flat install. Have room for about 16 of theses panels on just this one part of the roof (1st floor mudroom, larger roof surface on second floor).

At $1.80 per watt ( I know it can be had cheper, but am not fully committed to buying 10 or 20 panels at a throw), I guess I might have taken a step up in the solar hobby.

Thanks for all the advice I've received, notably, solar gary and WWW. :cowboy:

A bit late to ask, but did I not make a good purchase, considering the reasons and not the illusions of what it is?

Matt


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## 12vman (Feb 17, 2004)

Kudos for taking the jump to learn! Just don't expect too much and be disappointed like many folks do. Thoroughly study what you have and work within the parameters..

You have 2-115 aHr. batteries. Connected in parallel for a 12 volt system, 230 aHr. total. 25% of that is ~57 aHr. I'd round that to 50aHr..

Your 100 watt panel is going to supply ~5 amps of charge (per hour) on a good day. 20-25 aHr. during the summer. Winter.. *MAYBE 5-6aHr. all day.. A little more on bright sunny days.. (Our conditions are about the same) 

If you use 50 aHr. from your battery, it could take 6-10 days to replace the energy that you used during the winter with no load on the battery. Actually maybe longer if you consider the 20% loss factor of the battery. They only hold 80% of what you put into them..

Winter time max usage.. ~5 aHr/day. Summer time.. ~20 aHr./day. Using an inverter will kill that amount fast! (10 to 1 conversion factor) You could only operate a standard home computer for an hour and it could take days for your battery to recover. Just so you know..


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## Roadking (Oct 8, 2009)

Thanks 12vman, and for previous input (sorry I forgot to mention a few others above as well).

What you describe is right around where my studies and calculations ended up, and is what I was shooting for. Having the ability to expand in the future is in the works, this is just to get a feel for what I am doing.

I really don't see being completely off grid, but in time reduce my usage of the grid and add a bit more control in our lives, then the kids can go from there...LOL! Yes, they are interested and not even teens yet, so we are learning and working together.

Thanks again.

Matt


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## Jim-mi (May 15, 2002)

Another 'need to have' item is a Tri-metric.
With this unit you can measure the energy put in and taken out of your battery.
Way too many people skip this piece of equipment and are just guessing at their usage.
There for they always underestimate the charge / discharge rates and end up killing batteries from gross under charging.
I see way to often some one saying "Well I have a XXX rated battery and I can use that whole amount" . . .Totally wrong . . . .that battery will die very quickly.

It is super important to monitor what ever battery you have.
So that means that you can look at the figures displayed on the Tri-metric and say "opps got to shed that 'load' because the battery is discharged -below- where it should be" . . . (for long battery life) 

Don't short your self on charge controlers . . . .bigger and you can expand into it.


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## wy_white_wolf (Oct 14, 2004)

I've looked vat the Renogy its and they look pretty good compared to the HF kits.

One thing I would change is there mounting system. You want to mount the panels 6" above your roof for air circulation. Cooler running panels will perform better and cut down the chance of fire.

WWW


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## Roadking (Oct 8, 2009)

Thanks WWW, I had already planned to build a raised frame for that reason. Flush mounting didn't make sense from my research, also from an older thread where some folks brought up the cooler is better idea.

Thanks.

Matt


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## 12vman (Feb 17, 2004)

Glad to see that you're teaching your kids. The more they see, the more they understand..

We need a future of understanding people and there's only one way to get that. Thank you..!


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## Gray Wolf (Jan 25, 2013)

Don't forget about snow removal if your panels are too flat to shed the ugly stuff.

The best, cheap, thing everyone should get is a kill-a-watt type meter. You plug the meter into an outlet and then the 'thing' you are measuring is plugged into the meter. Reads out several things but the most interesting is how much power your refrig, microwave, toaster, mixer, tv etc actually use. The biggest power sucker in our house is the tv / DVD, sat box speakers - about 300 watts. Also good for measuring all those phantom loads from chargers, clocks,etc. - small alone but they add up. Awareness of usage pays off on-grid or off.

Good luck!


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## biggkidd (Aug 16, 2012)

We have 6 sets of the HF panels and be glad you didn't go that route. Looking at renogy 300w panels now. Haven't made up my mind yet. We have been off grid almost six years but still live like we are on grid. Its wasteful but enjoyable. My girls are a trip with the things they now know. You can't do any better than teaching your kids.

Good luck.

Larry 

12vman good to see your still alive and kicking. I bet you thought we fell of the face of the earth.


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## 12vman (Feb 17, 2004)

Hi Larry. Good to see you too! I'm like an 'ol fisherman. I might smell that way but.. 

Gray Wolf makes a good point. I have my panels mounted on a platform 20' off the ground. 12 yrs. ago it wasn't an issue for me to climb up there and clean the snow off but now I dread it. Even at a 45 degree angle the snow likes to sit there. If the snow isn't removed, ya miss a lot of charge. I plan to move them closer to ground level in the next few years..

I mounted my current system high because I didn't want the panels to get stolen. I now have a wife that's a pretty good shot and 2.4 kw to add so a project is in the makings..

My system will remain 12 volt because everything I have is designed to work with it. To change would require me to redo everything that I've constructed and use daily since '89 and I don't want to do that. Keep that in mind as you design..


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## Roadking (Oct 8, 2009)

Thanks all, storing all the info as it comes in.
Tri-meter and kill-o-watt are on my to get list.
Panel will be roof mount. My one son's window will give easy access for snow removal.
Have a quarry nearby, and dust is a big issue. How often should the panel(s) be washed? And how, the same as if washing windows?

Thanks!

Matt

P.S. due to arrive Thursday!


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## Jim-mi (May 15, 2002)

Systems I have installed for customers, and my own are all pole mount so that it is reasonably easy to clean off snow . . . . . .Which I need to do today . . .We got 8" of snow and underneath it is ice coated. . . . It is just for this reason I will never do roof mounts,
I use one 8' long handled, very soft bristle brush, to reach up to the PV panels.
Rain does the cleaning . . . . .But if I had too, a hose would reach the top panels.

Roadking I suggest you take a few minutes to look at and think about ground mount or pole mount.
No holes (leak) in the roof . . . .easy to expand . . . easy to clean.

Back track a bit and look at some of the pictures TnAndy has posted of his pole and ground mounts . . . . very good stuff........


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## Roadking (Oct 8, 2009)

Jim-mi, ground mount will greatly reduce my solar exposure due to neighbors tree line and our privacy hedge; I've been on the roof and did the solar study/survey (that came as part of a Heathkit solar heater project my wife's grandfather bought many many years ago and abandoned), an the location is optimal. I can fit 16 panels on this roof and 18 more on the next roof up.
Not concerned with leaks; home construction and carpentry were former businesses and occupations.
Access is via a large window that doubles as an emergency fire escape, with a drop down ladder from the roof. If necessary, I can use the ladder.
Have a brand new soft bristle push broom. I intend to utilize my apple picker handle extension to give me 16' of reach for snow removal.
TnAndy's pictures and system description have been a driving force for me to persue this project. It makes my head spin, and drool a bit. 

Thanks again, when it gets under way, I'll do some pictures.

Matt


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## Roadking (Oct 8, 2009)

Whoo hooo! Just arrived! And it's a sunny day...unfortunately, won't be able to get started until the weekend.

Any negative effects of a panel being in the sun if it is not connected to a battery? Just curious.

Matt


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## biggkidd (Aug 16, 2012)

I don't know for sure but I do know they tell you to keep them covered while installing. So it's probably not a good idea.

Larry
A World Away


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## Roadking (Oct 8, 2009)

sort of what I was thinking.
Thanks!

Matt


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## Jim-mi (May 15, 2002)

Being in the sun wont do a thing-----unconnected

The covering is strictly to eliminate current flow--sparks-- when hooking them up

And if in a series string high voltage DC is very dangerous.


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## Gray Wolf (Jan 25, 2013)

Jim-mi said:


> Being in the sun wont do a thing-----unconnected
> 
> The covering is strictly to eliminate current flow--sparks-- when hooking them up
> 
> And if in a series string high voltage DC is very dangerous.


Be sure you have no loads on at all when you make the final connections to a panel or battery or else sparks will fly. Use fuses/breakers and disconnects everywhere you are supposed to!

DC voltage in a system should not be thought of as a giant flashlight or car battery. DC, by definition, does not alternate like common household electricity. If you or a metal object connect + and -, DC does not "turn loose" like AC and the amperages involved in an off-grid system are VERY significant. I consider 48 volts DC, or more, to be more scary than 110 volt AC and thus we have a 24 volt system. Not that it isn't dangerous too. 

I'm a coward, or smart, and always remove rings and watches, wear plastic framed safety glasses, gloves and long sleeved shirts when working on the battery bank, panels or wiring. I also have dipped all the wrenches and screwdrivers I use in a plastic coating to cover all but the end of wrenches and tips of screwdrivers - so hopefully no fireworks if a wrench is dropped on a battery.

I also have two fire extinguishers and an ax in the battery room. 

Off-grid works! See our place at: offgrid150.simpl.com

Don


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## Roadking (Oct 8, 2009)

Oh, I just reboxed it until I could work with it...oh well, out of sight, out of temptation...LOL!

And I am well aware of DC current, from a young age; at 16 I went to install a new battery in my car. Wrench on positive terminal made contact with the fender...ZAP and basically welded the wrench to the fender. Dad quickly yanked off the negative cable. That was followed by a lengthy talk about electricity and safety in the shop...
Granted, makes a handy little impromptu welder if you are REALLY in a bind.

Nice place wolf, good luck with it.

Thanks all.

Matt


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## Roadking (Oct 8, 2009)

Silly maintenance question. Would a coat of wax occasionally on the glazing extend the life / prevent scratching for optimal absorption of solar radiation? Also for help in shedding our winter snow?

Thanks

Matt


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## Gray Wolf (Jan 25, 2013)

I never heard of waxing them, but then again ....... I'll keep an eye on this topic and see what works for others.

The "winter tilt" of the panels here seems to be enough to melt most snowfalls once the sun comes out. Only a time or two each winter do I have to dust off enough snow for the sun to do its thing.


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## Roadking (Oct 8, 2009)

Just something that crossed my mind...My '55 F-100's windshield lasted a long time by waxing it from time to time...as do headlight covers, etc.

Matt


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## Jim-mi (May 15, 2002)

Never heard of anybody waxing panels. . . .really not needed.

recently coated windshield of truck with Rain-X . . . . .Wow that stuff works well


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