bought 3450 watts of solar impulsively

[flying kurbmaster]

26 panels they vary between 125 to 140 watts, Sharp, Solartec, Mitsubishi,Neuton,Connergy , made in Taiwan, Thailand, China and a lot made in Japan. I had an idea that I could use them for my small house, does anyone know if it is possible to connect these together with the different wattages, manufacturers, they are all the same size physically, they vary between 2 and 6 years old, they are all around 17 to 17.5 volts Will any of this present a problem when trying to connect them either to a bank or to the grid. they cost me less then 25 cents a watt so I bought the lot, that was part of the deal all or nothing, but if they don't work for what I intend then I may have to sell them on.  I didn't really think this through but the price seemed right.

 

[jimindenver]

Woof, that's a lotta solar. If they are close enough in voltage they could go together in a PWM set up. Total should be over 200 amps in direct sun so a BIG controller. You separate them into their groups, pair them up and use multiple smaller MPPT controllers. How big is your little house roof anyways?

One issue is what you will use as a bank. You are talking a lot of power and in full sun the array would fire up my roof top air just like my smaller array can run the window A/C. A bank that will slurp up all that sunny goodness and store it for night time use is going to be massive honestly. at a 1 to 1 ratio you watts to Ah you are looking at 14 of the 8-D I use in my system. You can use a smaller bank but have to consider how well it can handle the power. Some batteries can suck up anything you can throw at them, others will fry if you force feed them too much.

In any event we are not talking running a few LED's here. You are looking full sized residential refrigerators, cooking and A/C on demand if it were set up right. It just depend on what you need and when. We use our solar to run things during the day and use hardly any power at night. Our big bank is intended to carry us through the bad times for a week.

Another notion is to figure out what you need power wise and what will fit on the roof as well as the battery bay. Take the rest and sell them off for a profit to pay for the controller and battery. I would be hinging them in pairs and selling them with a inexpensive PWM controller and wiring as portables. You could make a pretty penny that way. I'd love a set of 140w's to play with.

More info would help as far as how many of what panel/voltage/Isc. How many do you think will fit and what do you want to do with them. The panels were a great find, the controller, wiring, inverter and batteries are going to cost some bucks.

 

[wagoneer]

wow sounds like some crazy thing I would do, I would wind up taking the cream off the top and giving or selling the rest. I sold one of my 50w panels at the flea market for 75 dollars and it was 20 years old.

 

[BradKW]

Jim's response raises a question I've had: where does the power go once the battery is full? I sort of thought the CC must just turn off current, but if it's possible to fry batteries, maybe not?

 

[rvpopeye]

WOW,,,,,,You can power up the van and a house too !
Now you'll have to put your deal finding skills to work finding the rest of the parts ..

 

[jimindenver]

Brad
Hooked directly to the battery it would continue to raise the voltage until the battery was fried. The controller just stops using it. It's different with wind power for some reason, that needs a dump load if I understand right.

That's why some controllers have the ability to take the excess output and send it to a set of load terminals automatically but only when the batteries are not using it. A popular use is a second heating element for the water heater if the load limits will accept it. Some are set pretty low.

F.K,
I want to suggest you visit a few solar forums. They deal more with a system like you are looking at than what we see as RV types. They can be gruff, sometimes even rude but the info is there. I suggest some reading to catch up on the simple concepts and posting the more advanced questions once you have a idea of what they are. I can tell you that they will suggest at least a 24v bank if not 48v bank.

http://forum.solar-electric.com/categories

https://www.solarpaneltalk.com/

 

[BradKW]

Lol... yeah, gruff and rude sums it up. Posted there a few times after following your link about CCs... Solar king guy is a dick, but got the info I needed.

 

[jimindenver]

Now you know why I don't post there. They understand the larger systems but think they can do more through the 7 pin running the engine for 30 minutes than you could ever do with solar. It's a waste on a RV. I like to help, I don't have the energy to argue.

Still, without even posting you can find the info needed to handle a system this size on both sites.

Me, after running it through my head a few times. I would set it up like I have the trailer. At that wattage you could run anything that you could plug into a 120V/20a outlet and not touch the batteries for a good chunk of the day. That's a lot of stuff including small washer/dryer combos, A/C's bigger than I run, cook tops, microwaves, even small ovens.

The only thing is it is expensive to set up and wasteful if you are not using the power. That's why people either set up what they need or go grid tied. I was in heaven when I found my first panels at $50 each until it was explained to me that it was going to cost much, much more for the controller, inverter and bank to use them.

 

[flying kurbmaster]

yes I will be going to the solar forums with this one, I am thinking of tying into the grid, just wondering if that is possible as they usually have bigger panels at higher voltage, My plan was to put them on my garage roof, maybe a few on my porches, I also have a section of roof the length of the garage for shade, all tin roofs, The house is at the wrong angle to the sun and roof is wrong. I don't have AC don't need it, My plan was to convert the stove to propane and the water to on demand also on propane from those large tanks but maybe I can run the water heater on a timer with this much solar. I need to do a bit more research and I will not likely do anything for another six months as I am off to live in the Kurbmaster next week until winter. I can maybe set up smaller systems with different controllers. I also got as a bonus in this deal a Morningstar 45 controller, This all came from a rural internet provider that changed over the Morningstars for some kind of controllers they can remotely reset saving them field trips. The panels came from cancelled constomers, I may be able to get more controllers??? If I don't set this up I might become a used solar dealer, I think these panels would work well for campervans, and vandwellers one or two at a time. I still have to test them when I get a chance.

 

[rvpopeye]

MorningStar is good stuff !
You might also try asking one of the solar dealers for advice (AM Solar etc.)

 

[blars]

You can wire sets of identical panels in series for higher voltage (unless they will have different shading). Each set goes to it's own controller, bigger controllers usually are designed to be hooked together. You want MPPT controllers, morningstar has manuals online that show how to hook them together. For a larger system like this, you may want to go 24v or 48v batteries.

 

[flying kurbmaster]

I just read something about mini controllers or individual controllers or converters, for grid tie ins, I think, they were talking about how if you use these you separate each panel and it continues to produce at it's peak even if other panels are shaded or not working as well or of different sizes. ???? they were talking as if this is the way things are heading, instead on one large controller or inverter for the whole bank of panels,

 

[flying kurbmaster]

Jim's response raises a question I've had: where does the power go once the battery is full? I sort of thought the CC must just turn off current, but if it's possible to fry batteries, maybe not?

or maybe fry the controller, or start a fire somewhere?????

 

[flying kurbmaster]

MorningStar is good stuff !
You might also try asking one of the solar dealers for advice (AM Solar etc.)

yes I plan on doing just that there are quite a few companies in my area that are selling grid tie in packages, so I will go and pick as many of their brains as I can, I am in no rush, the plan is to get this place to as low overhead as possible before I get to a place where earning becomes a problem. We are well on our way with 29 fruit trees and vegetable gardens that get bigger every year, chicken coop that can be take a lot more chickens then the two we have,  I am hopping to generate income from this property as I get older and our knowledge of what does and doesn't work in our space increases.

 

[jimindenver]

Only if the controller malfunctioned.

You can leave a panel in the sun unconnected and nothing will happen. You can short it out too and the leads will handle more than it can produce. You short it out with a meter when you test for Isc. The controller will decide to cut off the power when right and the panel will just sit there. That is why you have a controller.

Things that will cause a controller to heat up are too small of wiring, Poor ventilation and running at peak or above peak for long periods, using a PWM to dump a lot of voltage and improper set up or poor connections. In most cases there are safe guards to prevent catastrophe like fuses and temperature monitors. They will shut the power off completely.

 

[flying kurbmaster]

well I managed to score a second Morningstar ts45 charge controller today and he will be holding a few more for me over the next few month as they do their switch over to the newer ones. Now I have to put a battery request out to the universe and wait to see what happens.

 

[rvpopeye]

It's beginning to come together !