Just started a large project .. ~2000 watts and building own panels.

[TTG]

Hi I have a couple of 100 watt panels, an 800 watt inverter, a 2500 watt inverter, and 4 golf cart batteries (in parallel and series, 8 & 6 volt, range of 14-15 volts), a 200 amp charge controller that is a disconnect at a certain voltage ~15.4 volts. Just bought ~2000 watts of solar cells. And, am now preparing for construction. As maybe you can tell from the description, I am doing this on a very tight budget. I'm thinking at this time I'll be cutting my own frames, pick up glass where I can find it, put diodes on myself, use solar-tite for encapsulation, shoot for about 16v output. Plan on keeping a 12v system with a rheostat (small wattage). Have thought about using clear seal or the like for encapsulation. Very small budget. Was thinking K-L copper tube for main connection bar(s). And, was wondering... any ideas on doing this cheaply with good longevity ???

[Mike90250]

Larger than 1,000w, and you should be looking at a higher voltage system, 24V at least. 12V there is too much current, as you discovered, and need to use copper pipe to keep losses down. That also benifits your charge controller expenses, you only need 1 @ 24V, or 2 @ 12V.

[TTG]

I'm sorry. I know enough to get into trouble. My system(s) as planned will have a total of 2200 watts possible. I'd like to keep the 12v style system in order to maintain battery and 12v appliance capability. The plan is to use k copper tube to the charge controller (200 amp), to the batteries, to the inverter. I'd rather do this. And, I understand that higher voltages carry more watts per amp. Meaning, less bulk on the wiring. But, if it's just less bulk then that wouldn't be a problem. So, the 16v panel design and the 14v batteries and the rheostat are my attempt to balance things. Your input is very welcome. And, thank you.

[Mike90250]

200A charge controllers, rheostat, 8V batteries, 6V batteries. I can smell the smoke already.

And better read up on charging batteries, 16V panels will never bring a 12V battery up to full, let alone, equalize. 17v is the absolute minimum, and most are 18-19V.

[TTG]

And, thus the reason I'm here. Although, parts of the system have been functioning for awhile... I'd still rather avoid the smoke/fire if at all possible. What seems to be the worst problem(s)??

The batteries are now at 14v (8+6), the panels put out ~17.8 volts(200 watts). I've never had it keep a charge above 15v. I get a quick curve upward after about 14.8 volts. This seems to me to be the limit. Thank you. I am underutilizing my capability at this time. As, it is not enough to power large appliances. Am I wrong?
The rheostat (DC dimmer) is for less than 100 watts total and haven't used it yet. Up until the time I use it, when my supply goes over about 14.7v I jump to a transformer off the inverter supply. But, I want the ability to not use the inverter when my supply is low. The 200 amp charge controller is being utilized without problems. Using an 800 watt inverter that can handle the <15 volts it gets. Aldready have a 2500 watt with the same voltage specifications. Don't need it yet.

The 12v rheostat is for appliances that won't use the inverter. As, I'd like to turn it off at times in order to conserve power.

I'm on the darkside of the day now. A little bit of sun is out. My controller has stopped clicking on and off. Checked my voltage and it's at 14.7. My charge controller is a Coleman Air that uses a 200 amp relay. So, a direct connection/or not. Does that help.

[TTG]

So, since my controller is a relay type and my batteries are at 14.7v charged it isn't a good idea to shoot for 16v and up the amperage? I read in the forum that when you "direct connect" solar panels the panels will operate at the voltage of the batteries. Since, I will be building these I'm hoping to be right. I hope you don't mind.

[Sunking]

a 200 amp charge controller that is a disconnect at a certain voltage ~15.4 volts.

Got a manufacture and model number for that 200 amp controller?

I am not to knowledgeable or bright about solar power and could use your experience in finding a 200 amp 12 volt controller for my project.

THX

SK

[Mike90250]

battery FAQ http://www.windsun.com/Batteries/Battery_FAQ.htm

There is no way, you are going to manage a 14V battery with a charge controller and a rheostat. Something will die, unless you devote your life to reading the meter and riding the rheostat while the sun is up. 200A controllers are a joke, since there is not a good reliable & affordable way to manage that amount of power. It likely uses a re-purposed contactor from a automotive starter motor, and even then, those are not made for 200A continuous use.

I have a concern that you are building a very large homebrew system and don't even know the right questions to ask about it, let alone take reasonable safety measures.

[Mike90250]

So, since my controller is a relay type and my batteries are at 14.7v charged it isn't a good idea to shoot for 16v and up the amperage? I read in the forum that when you "direct connect" solar panels the panels will operate at the voltage of the batteries. Since, I will be building these I'm hoping to be right. I hope you don't mind.

explain how you are wiring 6 & 8 volt batteries ? What is your target battery voltage? You need to have several volts above the battery voltage to force a charge into them, and nearly 16 V measured at the battery, to equalize a 12V battery. To get 16V at the battery, you have to feed about 19v into the controller.

[TTG]

Got a manufacture and model number for that 200 amp controller?

I am not to knowledgeable or bright about solar power and could use your experience in finding a 200 amp 12 volt controller for my project.

THX

SK

Coleman Air C40 controller w/200 amp relay

https://www.colemanair.us/vp_asp/scripts/shopexd.asp?bc=no&ccode=C40-12SG

They have a 440 amp relay

https://www.colemanair.us/vp_asp/scripts/shopexd.asp?bc=no&ccode=SEA440

I bought my relay through a retailer of their product.

[TTG]

battery FAQ http://www.windsun.com/Batteries/Battery_FAQ.htm

There is no way, you are going to manage a 14V battery with a charge controller and a rheostat. Something will die, unless you devote your life to reading the meter and riding the rheostat while the sun is up. 200A controllers are a joke, since there is not a good reliable & affordable way to manage that amount of power. It likely uses a re-purposed contactor from a automotive starter motor, and even then, those are not made for 200A continuous use.

I have a concern that you are building a very large homebrew system and don't even know the right questions to ask about it, let alone take reasonable safety measures.

The rheostat is not in the charge/inverter system. It is a separate system off the batteries for 12v applications of less than 100 watt total.
And, the relay is re-purposed from the automotive industry. With contacts for both contact and non-contact under power. These have been used by many people for solar and wind power for years now. Have you heard of any problems? What you say seems a little insulting. It is a large homebrew system. And, I am taking safety measures. If, I didn't care about safety I wouldn't be asking questions.
Although, in all honesty, I have been doing a lot of testing. And, during this time it is not as safe as I envision the final system. I really am sorry I cannot purchase top of the line panels, chargers, and batteries. I just can't afford that. So, yes it is a homebrew. And, yes I really do appreciate any help.

And, I am considering using a layer of solar-tite. Laying the cells. And, then another layer of solar-tite. Or, something to that effect. What's the best way to not have bubbles without vacuum or heat? And, yes the voltage question is still open in my book. Cause, that will effect the cell/panel configuration. I am trying to match voltages from panel to batteries to inverter. Otherwise the electricity has to go through a transformer and I lose efficiency/capacity.

[TTG]

explain how you are wiring 6 & 8 volt batteries ? What is your target battery voltage? You need to have several volts above the battery voltage to force a charge into them, and nearly 16 V measured at the battery, to equalize a 12V battery. To get 16V at the battery, you have to feed about 19v into the controller.

What you are saying has not been my experience at all regarding voltages. The 6 & 8 are wired in series. Totaling 14v. I have 2 (6 & 8)s in parallel. For a total of 4 batteries putting out 14v. The measured voltage over time does not drop below 14.2v (disconnected). The charged value at the end of the day is 14.7v-14.8v. My voltage at charge is only allowed to go up to about 15.4v. This has been charging them. The controller runs off the batteries. And, measures the voltage at the batteries. So, I'm not quite getting the 19 to 16 to 12 When I have 17 to 15.4 to 14.
Thanks. If this wasn't functioning well I wouldn't be contemplating upsizing. Isn't overcharging hard on batteries? Like I said, I know enough to get things wrong. But, we are talking about a very low budget.

[Sunking]

Coleman Air C40 controller w/200 amp relay

https://www.colemanair.us/vp_asp/scripts/shopexd.asp?bc=no&ccode=C40-12SG

They have a 440 amp relay

https://www.colemanair.us/vp_asp/scripts/shopexd.asp?bc=no&ccode=SEA440

I bought my relay through a retailer of their product.

You do understand neither of the Coleman devices are charge controllers right? They are Diversion Dump Load Controllers

[TTG]

You do understand neither of the Coleman devices are charge controllers right? They are Diversion Dump Load Controolers

As I understand it, the C40 is a charge controller. It measures the voltage and if it's "too high" it switches off. And, when it reaches a "low" it turns back on. It does not change the voltage in order to "top off" the battery. It does not protect the battery from over discharge. Although, one could.
(And, it is being considered to use one for that purpose. But, it would require the "power to" the main relay to be reversed by a relay in order to maintain "mostly unpowered" status. And, since this small reversing relay would be always on it would have to be robust. Any other ideas about a really cheap system disconnect for low voltage at 14v 200 amps?)
The "diversion load controller" aspect is for wind power in order to protect the windmill turbine. In solar applications a diversion load is unnecessary. Is that what you mean? And, thanks for the reply.

http://colemanair.us/ebay/Images/C40_HookupDrawingDisconnect.gif

[TTG]

I'm sorry I do have a tendency to give too much information in a slightly disorganized fashion. (ie Sunking - thinking the C40 isn't a charge controller and Mike - thinking the rheostat was integral to the overall system) It really is not your fault. It is mine. I do appreciate you both for spending the time to read and reply. And, value your insights tremendously. Please continue, I realize misunderstandings are more than likely my fault. Thank you.