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#21 [url]

Jan 22 12 7:48 PM

A lot of "off grid" houses have inverters so the whole house is wired for 110 AC just like "normal" houses.  Finding AC equipment and appliances is a lot easier than trying to find DC appliances and the electrical runs are a lot less expensive when using AC.  So, an AC pump could be used if the off grid house had an inverter.  

If it is a closed loop, does that negate any elevation changes made by the water?  If so, then a much smaller pump could be used. 

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#22 [url]

Feb 16 12 12:26 PM

So, I'm finally going to get 2 of the Grape solar panels from Costco. Gas is costing me too much on my midget of a budget.

But I'm scared and I need some help! I think I've got more than 200 hours of research under my belt in just the last couple of weeks and I'm still confused about the other components to make a total system. 

What I have so far is:

Two instapark charge controllers that are 8amps each from
6 6v golf cart batteries from Costco 
     With all the 4ga wires attached series/parr because I'm charging them with a generator
1 800 watt inverter

I'm thinking I can buy 10 ga wire (from where?) to run from each solar panel to their controllers and 
     then run the 10ga wire from the controllers directly to the batteries 
          And that will charge the batteries.

Fuses, breakers, combiner box for the controllers/panels...oh my, do I really have to?

Any help would be soooooooooo appreciated!  Pardon me while I wipe away the tears. 

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#23 [url]

Feb 16 12 12:31 PM

And, of course, I live in Eden Roc so I'm assuming I would still sometimes need to charge the batteries with my genny; so, would I remove the solar panel wire from the batteries to connect the battery charger so I don't back feed into the panels and fry them? Or, install some sort of toggle switch so I can just leave the solar panel wires on the batteries and charge them with the genny? 

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#24 [url]

Feb 16 12 12:35 PM

Basically you can forget the charge controllers if you want to save some bucks, as long as the charging ability of the panels isn't any more than about 10 percent of the capacity of the batteries-- in a small system one one a budget is generally better off with more batteries and less infrastructure. You'll need a switch to simply shut the PV's off if the system gets too high, which will be hard to achieve with a big bank of batteries. 

To clarify, say your panels make 15 amps x 8 hours -- 120 amp/hrs -- an ideal balanced battery bank should have at least a capacity of 1200 amp hrs. If you find you still overcharge, great! Add some batteries.

This works because batteries, of course, have internal resistance that increases as the charge builds, eventually you simply can't make the juice to charge them any more. Poof, built in charge controller.

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#27 [url]

Feb 17 12 5:33 PM

If it is a closed loop, does that negate any elevation changes made by the water?  If so, then a much smaller pump could be used. 


Sorry for the long wait of a reply...

Water seeks it's own level so, elevation doesn't really matter, as long as there is minimal restrictions such as 90's (bends in the tubing) and Not really really long runs like less of 500' of tubing than a smaller pump should be ok.

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#28 [url]

Feb 17 12 6:43 PM

And it is always good to have a volt meter on the batteries so you can tell when they are getting too low and need charging. You can get a nice single power digital for about $10 on Ebay from Hong Kong.
It  is nice to know when you have power and when you don't. You can also get 1 1/2 watt LEDs 110 or 12 volt lights for $2-3 shipped, a Lot of light for very little power. ( no inverter waste.)
The key is to know where you are using power and how to lower it.


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#29 [url]

Feb 18 12 9:25 PM

Awesome, Darren i'll call you tomorrow to see when you'll be able to talk story. Chat or email is fine, phone would be great, or in person if you feel comfortable.

I'll have to check this site to see where my email goes, i haven't gotten it yet.

Thank you so much!

Thanks Jay!
  I already have the 2 8amp charge controllers and trust me, no battery wants me as it's tender'er.  Also, i hope that i've coupled just about the right amount of watts with batteries so i get a pretty decent charge most of the time.  it's a very small system, not even 500 watts, but it'd be very difficult to replace anything I fry.

Yep, Bill, that's what i read lately and i've been searching for a volt meter. I saw some on amazon but I'll definitely check out ebay for those. Digital, for $10....score!  
And lights are VERY important to me.  I don't want to, but I can do without the tv...that was painful to say. But I think my use (overuse) of lights makes me feel normal (on the grid I guess) and the outside lights makes me feel like they keep the coodie coddlers away.

I got some 12vt light strips from amazon and they are awesome; as well as a 12vt 10 watt outdoor light; not for $2 to $3 though!  I'm such a devotee to; they've saved my butt so many times, but i'm gonna check out ebay for those also.

I'll post as my system comes together and some final results in case some are interested.  Maybe i'll become a youtube star...gotta love youtube, right!

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#30 [url]

Feb 19 12 8:15 AM

If you get down to low HPP give me a call and drop by I have build a 2500 watt system.9823273


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#31 [url]

Feb 20 12 6:49 AM

I was thinking of running a 12Volt system in my house.  Seems cellphone, laptop, a billion other chargers etc...etc... all can use 12 volts, even my router and cell phone plug ins.

So if I can get rid of all that low power wattage waste, Plus some 12volt for the lights.  What kind of wire are you guys using?  I'm going to wire in regular 120volt as well.  Can I just use a separate #14 romax wire for my 12 volt system.  I won't need the ground?  Or do you suggest I run some other type of wire?

What about the wire from the batteries to the panels?  Same wire?  I'm thinking of a small system maybe start off with two 120Watt Panels and a few batteries. 


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#32 [url]

Feb 20 12 9:46 AM

Hey Jay, I've run into a few boating and RVing websites that talk about their reasons for not bothering with a charge controller; especially with a smaller system like mine will be.

It seems that with lead acid batteries, as opposed to sealed gel batteries, if you don't let the water run as low as the plates, or boil them out, you can't really hurt them by over charging them. 

So, no charge controller is needed so long as you keep up with filling them with distilled water.

Isn't my rain water the same as distilled water......hmmmmm?

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#34 [url]

Feb 20 12 10:25 AM

Hi Eric,

I've found that for a 12v system, as opposed to 120v, the wire needs to be stranded; because, umm, well that info is lost in my memory bank somewhere. Heat dissapation?  More paths to conduct? Low resistance?  I may need a larger gauge wire for my mind's bank!

This website has a wire sizing calculator that is just awesome!

The real question is where to buy the wire. Home Depot, to my dismay, doesn't carry any low voltage wire that is a lower than 12/2. I bought the 12/2 for the gate, cheap! even cheaper. 

I'm thinking I'm gonna put my panels on my roof and running them to my batteries may be up to 30', so at 12v with 10amps max for my two panels at a distance of 30'  I'm supposed to get 8 gauge wire.  Very'spensive!  If I can keep the distance to 21' then I need 10 gauge...and at 13' it's 12 gauge. Maybe I should throw the battery bank on top of the roof also; I could build a little dormer. Pffff.

On Amazon, Hinkley 10-2 is less than $1 per foot, but you have to buy $250 feet. Anyone wanna coop?  Ok...just found Hinkley 8-2 100 feet is $239.   Ouch!

To lessen the distance, therefore the cost of the wire, I'd have to either move the battery bank or the panels.  I have to put them on the roof, or atleast somewhere that the coodie coddlers can't easily get to them. How about a loft bed type of thing, but a bed of sorts for the batteries. I can see drilling through the roof, or even the facia and having a distance of as little as 5 feet.  Gee....with 5' distance, I would need 16/2...A building I will go, a building I will go.....hi ho the dairy oh...wait....have to build a loft ladder too.

Will it never end?  Aaaaaaaaa hahahahahhahaaaaaa

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#35 [url]

Feb 20 12 10:36 AM

My neighbor just walked in and said a battery jumper cable wire can be as low as 6/2 and is a good alternative. So....on (just for example) 6 gauge at 12' is only $20. Or 12' 8 gauge is $14.

OmGoodness...So, for 24 feet of 8 gauge it's $28 or 36 feet it's only $42....sounds like a great answer to me!

Well, you have to do a great splicing, and I don't think it's rated for outdoor, underground or anything. So what do you wrap it with or do you run it in electrical conduit?  

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#36 [url]

Feb 20 12 10:45 AM

One more thing this morning before I put away the coffee pot which has been my best friend for the last week:

I'd planned on the Grape solar panels from Costco, right. So, I call them and ask how many they have left because they'd purchased a pallet.  They had 75 and now they have 70.  So, I thought, what happens when I can add to my system in the future, so I ask 'em....will you be carrying these all the time.  She says, "our system says when these are gone, they're gone". 

I called back and she connected me to "someone" near that department. It was a T and T Electric company "guy" who was promoting the Grape products (and I'm sure the installation of said products).
He said they may not be carrying that specific panel anymore, but will "probably" carry some variation.
I asked if they are mono or poly; he said poly....220 watts.

Then, I happened upon a craigslist ad where a guy is selling 185 watt mono's for $398....hmmm

Although, I love the drive to Kona because of the drive back...It's like a 2 hour movie where a dead planet slowly turns into a live 1.

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#37 [url]

Feb 20 12 11:46 AM craigslist guy Ray's solar panels are 24 volt.  I'd have to rethink the whole thing.  Sounds like a great guy and VERY informative! He runs a 120volt low energy refrigerator off of his system! Cool.

He said Costco's panels are probably not 12 volt.  How could I not have asked that?  They open at 11am...I'll confirm and let y'll know.

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#38 [url]

Feb 20 12 12:05 PM

So, Costco is closed so I called Grape Solar, located in Eugene Oregon.

He says the panels probably say something like 21.7 volts and he's going to send me an email to tell me what I need to set up a system based on my 6 Costco 6 volt batteries wired to be 12 volt so I can use the 12 volt inverter that I have.  

What he did say was "Basically you would need about a $220 charge controller". And he said "yeah, sure, solar panels are 'named' as 12 volt but their not actually 12 volt." 

I need some antacid. 

I'll post his email as soon as I get it.

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#39 [url]

Feb 20 12 12:18 PM

Grape Solar Panel Peeps Email 


There are two voltage numbers indicated on the back of a panel, one is if the panel isn’t connected to anything (Voc) and the other is for peak power production when connected to a charge controller (Vmpp).  Just because the Vmpp for the 220W panels is 30.1V (36.3Voc), doesn’t mean it won’t work with your 12V system.  The charge controller reduces the voltage of the panel to around 13.5V so that power will safely feed into your 12V battery bank.  When selecting panels for a 12V system, all you really need is an output voltage higher than 12V.  There is no such thing as a 12V panel, it’s an oversimplification for marketing.


When selecting a charge controller ignore the Impp on the back of the panel (current).  That’s just the current running through the panel.  You need to determine the current running through the charge controller.  To do this take the wattage divided by the battery bank voltage.  More specifically:


(2 x 220W) x 90% = 396W

396W / 13.5V = 29.3A.


For two panels, you will need a 30A charge controller.  Now back to voltage; most charge controllers have an input voltage limit of 25V.  You will need a charge controller that can handle 36.3V assuming you connect the panels in parallel.  I would recommend this one:


I hope this makes sense.  Feel free to call or email me if you have any more questions.


Garret Towne

Technical Sales Manager

Grape Solar, Inc.

1305 South Bertelsen Road, Eugene, Oregon 97402

Tel: 541.349.9000 x 14

Fax: 541.343.9000



Grape Solar, Inc. is the low cost leader in providing high quality solar panels.  We are headquartered in Eugene, Oregon, USA. Because we utilize contract manufacturing we can produce a much wider variety of panels than our competition.  We have it all, from 2.5W to 410W, mono or poly, black frames or silver, duty free panels, pre-designed solar kits, a residential leasing program, international locations, etc.  No matter the project size, you will always find high quality and aggressive prices with Grape Solar. Our products are available at leading chain and more…..

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#40 [url]

Feb 20 12 2:04 PM

ok...last post for a while.

So, Ray, the craigslist solar panel guys says he panels are really better for 24 volt systems; but can work on a 12 volt system with the right charge controller.  Something in the range of $400 to $450.  So much for my $20 instapark controllers good for 4.97 amps.  Amps don't mean a thing if your controller cannot handle the voltage coming out of the panel, apparently! His solar panels read 36.2 Vmpp, but 44.7 Voc.

The reason is the Vmpp; the Volts that the solar panels are putting out; even the Voc, which is even higher on panels.  

I looked at my battery charger that I bought from Napa because it charges all 6 of my 6volts completely in like 3 1/2 to 4 hours.  I have it set at 40 Amps @ 12 Volts.  So, I'm assuming the equation of w = v * a in my situation would be 480w = 12 * 40....and so I would need 480 watts of solar panels which either the Grape from Costco or Ray's panels would be pretty close.

Now, I think I'm going to have to find $225 atleast to buy the Blue Sky Energy's Solar Boost charge controller or one similar for the Grapes at 36.3 Voc or a much more expensive one to handle the 44.7Voc of Ray's.  

But, the Costco panels are Poly's and Ray's are Mono's.  Back to the drawing board. 

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