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Old 20-11-2006, 19:25   #16
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And another site I got put onto that may have answers, or confusion.

It does have a forum as well.

Dave


http://www.exploroz.com/vehicle/electrics/solar.aspx
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Old 20-11-2006, 19:36   #17
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And of course this bunch of hippies at Nimbin might be able to help if their not all stoned They also have a forum in the information column.

Actally got put onto these guys by Xantrex

Dave


http://www.rpc.com.au/reindex.html?h...ridge_faq.html
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Old 01-12-2006, 04:40   #18
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just wondering when your sizing a regulator to meet your solar needs do you need to have a fudge factor or can you take it that the output of the panels in amps will never exceed their isc rating
scenario 1 2 panels that have a isc of 5.5 inseries they will put out 11amax the reg i am looking for has a max input of 12amps so this would be fine
scenario 2 using
US Safety Figure 1.56 would give us 17.16A (1.56 x 11.0A, safest ‘regulatory safety margin’ between AUS and other country Authorities)
which is more than the 12a max input in the regulator i wish to purchaseso i need to purchase a biiger reg

i would value an expert opinion as i hate to void insurance or warranty through some stupid oversight
sean
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Old 08-12-2006, 23:58   #19
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address to a really good forum with info on solar
http://www.wind-sun.com/smf/index.php?board=4.0
sean
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Old 28-05-2011, 09:31   #20
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Re: mppt regulators

Hello All,
I heard the best situation is to go with high voltage solar panels (say 25volt or 30 volt panels) and to wire them independently to the charge controller. This way, if a panel is shades, it does not affect the other panels. Also, choosing higher voltage panels, it handles the resistance issue beautifully, while also handling the shade issue the best way possible. Am I right on all of this? Other than using much more wire, is it a better setup? Thanks Ron
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Old 28-05-2011, 09:51   #21
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Re: mppt regulators

Hello,
I heard that wiring each solar panel independently and directly to the mppt controller is the best method for beating shading. And if you choose high voltage solar panels (like 28-30 volts) then it nicely handles the voltage loss issue as well. I heard this is the best situation. Is it true?
Also, for great prices on solar panels, I found this website where I can buy a 150 watt panel @ 34.4 volts for just $261.00. How can i beat that?
cheers!
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Old 28-05-2011, 09:58   #22
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Re: mppt regulators

Quote:
Originally Posted by Ronald Rogala View Post
I heard the best situation is to go with high voltage solar panels (say 25volt or 30 volt panels) and to wire them independently to the charge controller.
As long as you use the appropriate gauge wire, it makes no practical difference whether you wire separate runs from each panel to the controller, or (with heavier wire) "bus" the panels together at the panels and run a single pair of wires to the controller. Either way the panels are wired in parallel. A bussed panel interconnection may be more prone to corrosion problems at the connectors, where one bad connection can take out all of the panels, but with proper connection techniques this won't be a problem.

On a boat, in most cases you will have better performance with paralleled panels (rather than wiring them all in series), because of the shadow issue.

You might get better performance by giving each panel its own MPPT controller, but it's not clear to me that the cost of the additional controllers would justify the (probably) small amount of extra power.
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Old 28-05-2011, 10:02   #23
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Re: mppt regulators

Hello there,
I read in one of these posts that they said the "Outback" mppt solar regulator was the most efficient. I just looked and the outback is rated at 98.1% efficiency while the "Morningstar" mppt was rated at 99% efficiency. I just looked at the 60 amp units.
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Old 28-05-2011, 10:11   #24
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Re: mppt regulators

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Originally Posted by Paul Elliott View Post
As long as you use the appropriate gauge wire, it makes no practical difference whether you wire separate runs from each panel to the controller, or (with heavier wire) "bus" the panels together at the panels and run a single pair of wires to the controller. Either way the panels are wired in parallel. A bussed panel interconnection may be more prone to corrosion problems at the connectors, where one bad connection can take out all of the panels, but with proper connection techniques this won't be a problem.

On a boat, in most cases you will have better performance with paralleled panels (rather than wiring them all in series), because of the shadow issue.

You might get better performance by giving each panel its own MPPT controller, but it's not clear to me that the cost of the additional controllers would justify the (probably) small amount of extra power.

Hello Paul,
thanks for the clarification. It makes logical sense, if the panels are wired in parallel, then many wires going to the mppt controller, vs one thicker wire going to the controller, its the same as long as the wire size can handle it equally the same. Unless the charge controllers have separate lugs for different inputs for the panels. Then the controller can pretend the shaded panel is not there while not reducing the inputs of the other panels. But i dont know if the expensive charge controllers have only one input attachment, or many input attachments for the panels.
cheers.
Ron
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Old 28-05-2011, 10:29   #25
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Re: mppt regulators

Personally I sum my panels at a breaker panel before going into the controller. The panel and breakers didn't add much to the cost and gives a little more flexibility and safety if you need to work on the system.
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Old 28-05-2011, 12:17   #26
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Re: mppt regulators

Can you explain the pro's and con's in regards to wiring in series as to parallel?
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Old 28-05-2011, 12:59   #27
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Re: mppt regulators

In series you get an increased voltage but the current remains the same as one panel so you get less loss to resistance, which means you can use smaller wires. In parallel you get the same voltage as one panel and the current increases. When cells are wired in series the whole batch operates at the efficiency of the lowest producing cell. A little shading on a panel has a hugh effect. When your panels are wired in series the shading on one panel impacts the other panels. Not so with parallel wiring.

If you have a 12v battery system and a different output from your panels you will need a device that handles the conversion.

I wired parallel although my MPPT controller would handle the conversion because of the placement of my panels. It's not uncommon for one to be shaded particularily when I'm sailing.
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Old 28-05-2011, 13:27   #28
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Re: mppt regulators

Thanks for the reply. I have just installed to 135watt Kyocera LPU panels on my arch and have purchased a Morning Star Duo controller. I will be about 30ft away from my battery banks. I have many options as to wiring route. It seems that parallel is the way to go. Any advice as to wiring size, join the panels in parallel at their location or at the controller? Does the line need to be fused if I am using a controller? Grounding etc. Any assistance is greatly appreciated.
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Old 28-05-2011, 14:20   #29
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Re: mppt regulators

I ran the calculations for 10 gauge wire and your system. The numbers aren't true because you'll never achieve perfect efficiency but a 30 foot run at 12 volts and 22.5 amps will lose 1.41 volts along the way, 8 gauge will lose 0.89. The same 10 gauge wire at 11.25 amps and 24 volts (serial wiring) will lose 0.7 volts.

Recommended wire size for 12 volts is 5 gauge but you would have the same efficiency with 10 or 11 gauge at 24 volts.


I don't think a line has to be fused but it adds some flexibility I guess. If you are worried about shading then summing where the panels are and running 24 volts the rest of the way will keep the wire gauge down.
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Old 28-05-2011, 14:21   #30
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Re: mppt regulators

Speaking of calcuations:
Wire sizing calculator for Solar Panel Arrays
Voltage Drop, Power, Battery Calculator
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