2160Watts Flexible on a Catamaran Optimization Questions

[Guest]

Currently I am running 12 180w 39.8Voc(V) 5.48Imp(A) flexible solar panels on my catamaran. They are configured in series of two for 79.8voc and then paralleled in groups of six for 32.88amps. These charge my 16 series 400ah Winston cells along with a couple dc generators, and two shore chargers. I run all the charging sources through a http://www.colemanair.us/shared/Dive...VA_CURRENT.PDF

This works quite well enough and is very robust as a standard charge controller so neither pwm or mppt. I am wondering though if I wanted to try a mppt controller which might be suitable and how to configure my panels? I was thinking of trying them series connected in 3 for 119.4Voc and 21.92 amps and if I would get a better charge rate from them.

So far the boat has had a number of test runs and performs as expected moving the catamaran around for only 30 amps upriver against current. Some videos of the times it was out on the water here https://www.youtube.com/channel/UC6B...cixqeoS1XlLYww

I did have all the panels wired into a combiner box on the boat behind the radar but I'm not big on that idea. I then discovered MC-4 In-line fuse holders so will be purchasing six of those and doing away with the combiner box and cleaning up the octopus there before it enters the cabin roof.

I have been looking at http://www.epsolarpv.com/en/uploads/...5121966928.pdf as a suitable candidate but how would I wire the panels to work with this controller?

Thanks for any help and letting me post.

[solar pete]

Hello Pacific Green and welcome to Solar Panel Talk. Your post was shunted of to be moderated as it has links in it. This type of solar set up is really not my gig, other's around the place may chime in, cheers.

[Guest]

Hi Solar Pete, thanks for posting it with the links. Seemed hard to explain otherwise. Hoping others do chime in as it would be nice to get more efficiency out of the panels if possible.

[Mike90250]

Hi.
A couple ideas to share with you.
Combiner box. Do away with it why ? The MC-4 inline fuse holders CANNOT be opened under load. They will arc and ruin the contacts, Anyone troubleshooting the system needs to know and understand why they will arc. And there are reports that some brands of MC-4 are not really weatherproof, and get corrosion inside, Has the combiner box suffered any more than would be expected in a wet environment?

Moving to an MPPT controller will only improve the BULK efficiency of the charge. All MPPT controllers have a PWM controller inside, that takes over when the MPPT advantage is no longer needed. So I think the only efficiency gain will be reduced copper loss due to higher voltage runs. Only a couple % better. Now if the batteries are always low and you have to run generators a lot, the MPPT gain is only about 20% - 35% depending on the mismatch between array voltage and battery voltage. Or it may be that the thin film flex panels are degrading (most only have a 5-10 year warranty) and you have lost power that way. Only new panels can cure that. Knowing the issues that are driving your thoughts to re-wire to gain more power, would be helpful.

[Guest]

The combiner box has no fuses in it. The entire line is protected only by a breaker before the charge controller. I'm using four 1 to 3 branch connectors and plug into that little box with two strings one each from the port and starboard. I could have just as easily branched the 4 leads down to two and run it to the charge controller without the box being attached to the roof of the boat.

I've never really discussed the system with anyone so I'm just wanting to see if I can improve on it. The standard charge controller seems to work very well. A few times last year I was able to see over 20 amps on the controller and in the one video I have over 17 amps on the controller. Given the positioning of the panels I'm mostly content with the return but then I've never seen them in full summer sun yet. The gear is all two years old used for 6 months.

I see I should have posted this in the off grid forum area.

[Guest]

So if I search Ebay for solar combiner boxes that some here make themselves (I've seen the pictures and read the thread) can anyone recommend the correct combiner box for the top of my boat to hook my solar panels up to.

I've seen it a few times repeated:

https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/341630-newb-with-questions-grounding-charge-controller-amperage?p=341859#post341859

https://www.solarpaneltalk.com/forum/solar-panels-for-home/solar-panel-system-equipment/17189-combiner-box-question/page2

etc... I've been reading them all and trying to wrap my head around what exactly I need to purchase. Since I could not source 48v flexible solar panels I opted for 24v panels in series and parallel and now end up at a combiner box with fuses.

Here I list all the specifications for my panels:
SYFD-FSPC180W-1
System Voltage 24V
Vmp(V) 32.92V
Imp(A) 5.48A
Voc(V) 39.80V
Isc(A) 5.85(A)

I have 12 of these panels.

How do I best connect these to a combiner box and if required the purchase of new solar charge controller(s).

Which combiner box do I need to buy?
1) http://www.ebay.ca/itm/6-String-Sola...8AAOSwA3dYJA6i
2) http://www.ebay.ca/itm/Solar-Combine...AAAOSwTapV4dWQ
3) http://www.ebay.ca/itm/MC4-Connector...0AAOxy7S5R8-IM
4) http://www.ebay.ca/itm/Safe-6-String...IAAOSw44BYPnEF
5) http://www.ebay.ca/itm/6-String-Sola...MAAOSw2XFUecoJ
6) http://www.ebay.ca/itm/Solar-Panel-C...sAAOSwPhdVDXTt
7) http://www.ebay.ca/itm/PV-Solar-2-St...VsIuUUV4QIRw9A

I like the last on #7 and is that the correct choice? I mean it looks good but shouldn't it have a ground wire coming out of it? Sorry about all the links again.

[SunEagle]

I still don't know what your 16 400Ah Winston battery system voltage is supposed to be. So it is hard to tell how you want you wire those 12 180w panels.

[Guest]

I apologize 48v nominal. Cells are managed with voltage sense boards and a contactor:
High Voltage Disconnect: 57.6V
High Voltage Warning: 55.2V
Low Voltage Disconnect: 46.4V
Low Voltage Warning: 49.6

[Guest]

I think the Eco-Worthy Combiner box is starting to look pretty good right about now. I'm waiting to hear back from them regarding fast shipping. The product seems to cover all the bases. I like that it uses MC-4 connectors.

[SunEagle]

I think the Eco-Worthy Combiner box is starting to look pretty good right about now. I'm waiting to hear back from them regarding fast shipping. The product seems to cover all the bases. I like that it uses MC-4 connectors.

Well the Eco Worthy might be over kill with 6 strings since you plan on only using 4 but it seems to be a nice little package.

[Guest]

And that is what I'm saying. Should I run all six of my series strings of 2 up to a six way combiner or should I just go with 2 strings into a combiner the way I'm doing it now? I can't seem to find a 2 way that has all the back current protection and other features the six way one has.

[Guest]

Examining the efficiency of:

1) http://string-calculator.morningstar...1&modulenum=12

vs

2) http://string-calculator.morningstar...=6&modulenum=2

With the latter string configuration being realized with what I have now but with zero MPPT functionality using the Coleman Air 440HVA.

I believe I satisfy NEC 690.80 by having a single 50 amp manually reset breaker before the homerun wire hits the charge controller. Then again absorbing the NEC code and interpretation with ABYC understanding will bring more understanding of off grid boat PV installs.

Otherwise I'm seriously entertaining the thought of purchasing a TS-MPPT-60-600V-48-DB (With Disconnect Box) provided:
A) That I understand completely that I need or don't need another external 50amp 600v DC Disconnect Box.
B) The acquisition will make my panels more efficient.
C) The grounding of the TS-MPPT-60-600v-48-DB can be accomplished safely on my boat.

In step 10 of the manual for these Morningstar controllers they call for a GFPD and I'm looking for clarification on that point in a mobile marine off-grid application.

[SunEagle]

Based on that EPEVER CC it can only handle 150v DC which is a max of 3 of those panels with a Voc of 39.8v. So you would have to have 4 strings of 3 with 12 panels. You could go with 6 strings of 2 but I don't see any advantage.

Another option would be to find an MPPT that can accept a higher DC voltage input like that Morningstar which is a pretty nice piece of equipment and then you don't need any over current devices by having 1 single string of 12 panels but should have a single disconnect to isolate the panels from the CC.