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Discussion Starter · #1 ·
We are wondering if these panels can be hooked up to each other in a series by running the wieres to one and then another panel?

We have just purchased two Kyocera Solar KD-135GX 135 Watt 12 Volt Solar Electric Panels and one Solartech 85 Watt Multicrystalline Solar Module.
We purchased them from solar-electric.com/ and they said we need a Midnite Solar MNPV6 Solar Panel Array Combiner box. So we also purchased one of those.
We have another Kyocera Solar KD-135GX 135 on the dodger that is now set up directly to the controller.


During instalation

The one on the dodger will also need to be hooked to the other three by the box or?

I am wondering if the person at solar-electric did not understand me. It could be they are corect but we would like another openiomn :rolleyes: We would like to run one wire or two from one panel and then from that panel to the next panel and so on. That way there would be two (+ - ) wires coming down from the bimini.



Our boat neighbor has the older style panels with one wire and he has two panels. One is hooked to the other then to the controller.

If we set it up to the box and the box is in our lazarett then we will be running six wires down from the bimini. These are not small wires.
I am thinking the good thing about this is that each panel gas protection with a breaker. Also if one panel should fail it would not affect any others.
However I am not sure I know what I am talking about.










During instalation
 

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Do you have a 24volt DC electrical system? If not, it's not clear why you would want to hook up your panels in series.

As for whether it can be done, it looks to me like those panels have some proprietary plugs connected to them. To hook up your panels in series, you'd have to cut off those plugs and connect the negative terminal of one panel to the positive terminal of the other. The remaining positive and negative terminals could be reattached to one of the removed plugs.

Seems very unlikely that this is something you should do.
 

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Discussion Starter · #3 ·
OK it would be Parallel wiring.
We have
3 - 135 watt panels
1 - 85 watt panel
We have a 500 watt controller.
So we want the four panels to total the 485 watts going into the controller.
If we go with this install using the box each panel will connect to the box (to a breaker) then the box will have two wires (+ -) that will connect to the controller.
We were just not wanting to run the six wires down into the boat from the bimini. If we wired the panels in parallel there would only be two wires going into the boat from the bimini not using the box.
I guess this whole thing is bit of splitting hairs as it just not that big of a deal.
We will run the six wires into the boat using a through deck fitting and be done with it.



Thanks,
Chip
 

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You can hook up the panels in parallel. Their amperages will sum. Make sure the wire that takes the current to the batteries is big enough for the maximum current the panels will all put out together.

By the way, I count 490 watts, not 485.
 

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I am relatively new to solar and am trying to learn. With that in mind, someone please correct me if I am wrong.

You can wire the panels in series to increase the voltage or parallel to increase the amperage. The 3024i charge controller appears to expect either 12 or 24 volt input. With that in mind, wiring the panels in series is not an option (as the voltage would be too much for the controller). So, I'd wire the panels in parallel and set the charge controller for 12V input.

The combiner box is completely new to me. However; it appears to offer some benefits - particularly in a home type environment where there are many more panels that we typical fit on a boat. I believe it is optional in your case. As previously noted, if you wire the panels in series, you probably need to use 10 gauge wire for the run to the charge controller (depending on distance).

JdFinley.com | Sailing, software development, and life…
You can observe a lot just by watching.
 

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It looks like their "combiner" is just a breaker box with bus bars, and frankly I'm not sure there's any need or use for it. Why wouldn't you just combine (parallel) all the panels into a small watertight junction box on the bimini, and bring two heavier power cables down into the boat?
 

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You don't need the combiner box. Along with it being designed for fairly large arrays, much larger than you have, it is designed to use non-marine breakers.
http://www.midnitesolar.com/pdfs/MNPV_Instructions_Rev_A.pdf

Parallel the panels at the bimini as hellosailor posted and run 2 larger wires into the boat, sized for minimal loss at whatever distance it works out to be.
 

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My understanding is the 3024i is limited to 30A. Under ideal conditions your panels are going to exceed this. I think the 3024 self limits so should not be damaged by the current (but please check), but it seems a shame to throw away power even if it will only be a small amount.
The other problem is the 2 different types of panels you have. These will not share the same Power point making the regulator less efficient. Under some circumstances MPPT regulators can become confused with different panels and lock on to a very wrong power point, this can waste a lot of power.
You could solve both problems by using a second small regulator and feeding the Solertec panel through this.
 

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Discussion Starter · #10 ·
Junction box

You don't need the combiner box. Along with it being designed for fairly large arrays, much larger than you have, it is designed to use non-marine breakers.
http://www.midnitesolar.com/pdfs/MNPV_Instructions_Rev_A.pdf

Parallel the panels at the bimini as hellosailor posted and run 2 larger wires into the boat, sized for minimal loss at whatever distance it works out to be.
OK I just canceled my order for cabling for these three panels as they were long cables. I can return the combiner box also with the breakers.

I did order a 30' #10 cable so running the panels below as I was originally going to put the combiner box on top of the bimini so I am OK with the larger cable, curt in half 15' should be long enough.

The junction box seems the way to go.
Now to find a junction box :)
Thanks,
Chip
 

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Discussion Starter · #11 ·
Sorry my controller is a 3024iL Duo

My understanding is the 3024i is limited to 30A. Under ideal conditions your panels are going to exceed this. I think the 3024 self limits so should not be damaged by the current (but please check), but it seems a shame to throw away power even if it will only be a small amount.
The other problem is the 2 different types of panels you have. These will not share the same Power point making the regulator less efficient. Under some circumstances MPPT regulators can become confused with different panels and lock on to a very wrong power point, this can waste a lot of power.
You could solve both problems by using a second small regulator and feeding the Solertec panel through this.
Sorry my controller is a 3024iL Duo
I just got off the phone with Blue Sky and my controller will support 540 watts. I kind of knew it would support at least 500 watts as I have been using it for a year or so now and just bought more panels. I was not sure though. I did not state the exact controller, mine is the 3024iL Duo.
Blue Sky also said the panels will work fine together. They said as long as the "Open Circuit Voltage" is within ½ they will work fine together and they are within ½.
Got lucky I guess but this panel is also a recommend replacement for the discontinued Kyocera 85 watt panel.

Kyocera
Open Circuit Voltage (Voc) 22.1 - 135 watt

Solartech
Open Circuit Voltage (Voc) 21.9 - 85 watt

Thanks,
Chip
 

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If all the panels are putting full output down one set of 10AWG cables, that's 485W or some 485w/17v=28 amps?

You may still be surprised, there may be 1.5v drop in the cables! The cable length still counts as 30' (the round trip) when you figure losses. I'd size up on the cables, till it is painfull to buy or install them, and squeeze every last volt out of those panels.
 

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Discussion Starter · #13 ·
Ok just found this in the controler manual.

"The 3024 will provide the best MPPT current boost performance if all PV modules are identical. If module types are mixed, do not put dissimilar
modules in series. Dissimilar modules in parallel should have VMP values within ≈0.5V or better for 12V modules, and be of the same basic cell technology so
their VMP will tend to track as operating conditions change."

Chip
 

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I agree with hellosailor - 10 awg is too small.

For a 30' run with 28 amps 10 awg is a 10% voltage drop. 6 awg gives you 3% drop and 4 awg gives you 2% drop.
 

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Sorry my controller is a 3024iL Duo
I just got off the phone with Blue Sky and my controller will support 540 watts. I kind of knew it would support at least 500 watts as I have been using it for a year or so now and just bought more panels. I was not sure though. I did not state the exact controller, mine is the 3024iL Duo.
Blue Sky also said the panels will work fine together. They said as long as the "Open Circuit Voltage" is within ½ they will work fine together and they are within ½.
Got lucky I guess but this panel is also a recommend replacement for the discontinued Kyocera 85 watt panel.

Kyocera
Open Circuit Voltage (Voc) 22.1 - 135 watt

Solartech
Open Circuit Voltage (Voc) 21.9 - 85 watt

Thanks,
Chip
Glad you checked, the manufactures are usually good at providing advice as long as you can get past the marketing department.
My internet access is very limited on the boat, so I am sorry I cannot check the information, but if you are sure the controller will cope with more than 30A of solar you should be OK.
Ideally for maximum MPPT the panels should be same, but if the VOC is similar along with the temp coefficients the practical results should be OK
 

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Discussion Starter · #17 ·
cables

I agree with hellosailor - 10 awg is too small.

For a 30' run with 28 amps 10 awg is a 10% voltage drop. 6 awg gives you 3% drop and 4 awg gives you 2% drop.
We have a solar panel on top of the dodger so I am not sure what the benefit would be in putting a junction box on top of the bimini as we would then need to run two cables from the dodger to the top of the bimini and then to the junction box. These would need to be larger say 4 awg and so it would negate any cable savings. There would be still four large cables to and from the bimini which is about the dia of six.
I am thinking the junction box would go in the lazerett and that way the solar panel on top of the dodger (two normal size cable which are there already as the dodger solar panel is working) would meet up with the bimini cables (4 awg) in the junction box and then it is a short run to the solar controller. How's that for a plan?

The controller box will be getting returned.
We will be sending back the controller box and the breakers as we think a simple junction box will work better.
The breakers in the controller box do serve as some protection and they are plastic. The box is water proof. They still would eventually rust though so it is going back.
Thanks for the help on this engineering,
Chip

One of the Bimini solar panels being set up - it is just wire tied on for now
 

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Discussion Starter · #19 ·
cable size for dodger panel

Chip

What do you mean by "2 normal size cables"?
The cable I ordered for the first solar panel about a year ago from Solar Electric Power Systems For On & Off Grid went from the dodger to the controller which is in back of the nav station. I am not remembering how many feet it is now after installing the cable. We ordered a 30' cable and cut it in half and I think then cut about three feet off that or so but my memory is not as good at 65 (birthday tomorrow) as 35.


Looks like the same size as comes with the panel.​



I will need to look at the cable to see if there is writing on it. Possibly I could find the invoice or get them to look it up when we re-order more cable.
What should it be? 4 awg or possibly 6 awg for 12 foot?
 

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Discussion Starter · #20 ·
Brian,

Perhaps I could get some guidance here.
For say about the 15 – 20 foot runs from the bimini to the solar junction box what size cable do I need?
4 awg cables?
And what about the dodger cable, does it need to be a 4 awg?

Can you point me to a solar junction box on the web? It needs to support four solar panels. I see too many that it is confusing.

Thanks,
Chip
 
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