Help...Wiring 12 Solar Panels

[mitiempo]

Originally Posted by StuM

But worse, the maximum PV input power for 12V is only 510W.

In other words, contrary to your belief, your controller can't handle the 720W from 12 x 60W panels going into a 12V system.

I agree. A different controller is needed.

A good controller such as a Victron will limit the wattage to its rating making the extra panel wattage useless.

An inexpensive controller without this designed in safeguard will likely melt first sunny day.

[ski69sail]

Thanks For All The Input

But how do I connect all the panels together.?? I did intend to connect the panels together using 2 separate bus bars with six panels to each bus bar and then connect the bus bars with one cable to my a MPPT controller.

It sounded so simple before all the issues were pointed out......I could go for a smaller system, but why ?? I want to be able to run all the stuff on my yacht and there is heaps of it.

Raymond

[sailormed]

Nobody mentioned that the panels are going to be used in New Zealand, a country where the sun is never right above you.
Normally for a fixed installation flat on the boat you will never get more then 70% of the capacity of the panels due to the slant sunlight on the panels.
Doing a quick calculation 0,7 x 720W = 504W.

Conclusion, the OP has the right controller for the panels!

[Blue Stocking]

Originally Posted by sailormed

Nobody mentioned that the panels are going to be used in New Zealand, a country where the sun is never right above you.
Normally for a fixed installation flat on the boat you will never get more then 70% of the capacity of the panels due to the slant sunlight on the panels.
Doing a quick calculation 0,7 x 720W = 504W.

Conclusion, the OP has the right controller for the panels!

+1, was wondering about this myself.

[StuM]

Originally Posted by sailormed

Nobody mentioned that the panels are going to be used in New Zealand, a country where the sun is never right above you.
Normally for a fixed installation flat on the boat you will never get more then 70% of the capacity of the panels due to the slant sunlight on the panels.
Doing a quick calculation 0,7 x 720W = 504W.

Conclusion, the OP has the right controller for the panels!

AT midsummer in the Bay of Islands, the sun reaches about 78°. Which could well give him 90+% of rated output (650W)

[sailormed]

I don't know for the MPPT controller of OP, but my installed Morningstar MPPT controller has an overcurrent protection. I suppose that other MPPT controllers have the same. This is of course, within reason, so I would not worry in the situation of the OP with his installation.

[mitiempo]

Originally Posted by sailormed

I don't know for the MPPT controller of OP, but my installed Morningstar MPPT controller has an overcurrent protection. I suppose that other MPPT controllers have the same. This is of course, within reason, so I would not worry in the situation of the OP with his installation.

Good controllers have protection but many don't. Having seen melted controllers I would get another controller.

Don't forget that when colder panels have a higher output.

[StuM]

Originally Posted by sailormed

I don't know for the MPPT controller of OP, but my installed Morningstar MPPT controller has an overcurrent protection. I suppose that other MPPT controllers have the same. This is of course, within reason, so I would not worry in the situation of the OP with his installation.

Using a max 510W controller on a 720W set of panels doesn't make sense for any number of reasons, even if it has overload protection.

Considering the additional cost and the number of years it will be expected to last, I'd definitely replace it with a controller that can safely use all of the Watts available. Why cripple his system with one that will be running at its maximum capacity and dumping energy a lot of the time and which will not be able to use up to 1/3 of the panels' potential output - even if it doesn't burn up immediately.

[StuM]

Back to the OP's question. I'd probably wire them up as six parallel "pairs in series". or four parallel "triples in series".

[ski69sail]

Hi StuM

Once the panels are wired to the two bus bars. Each bus bar with 3 pairs of solar panels wired in series, can the cumulative voltage cause any damage. ?? Are there any additional precautions that need to taken ??

PS how is PNG

thanks

[smac999]

You want to split it into 2 arrays with 2 controllers. This means neither array will exceed 30a and you won't need to fuse each panel seperaty. Just one between each controller and battery, and You won't exceed the rating of the controllers, and you have redundancy if one fails.

I would consider running each array in 2s 3p. For a 34v max array. Or 6p.

[ski69sail]

Hi

I previously considered splitting the array into two separate systems. My concern is about trying to keep the whole system as simple as possible.

But now it might be the easiest option to utilize my new under size MPPT.

Thanks

[smac999]

It is the easiest way otherwise you'll need 12 fuses up on the arch if using one controller.

[ski69sail]

Hi smac999

I was intending to use only one fuse on the feed to the MPPT. Then another on the feed to the batteries
Again in the interests of simplicity.

Thanks Ray

[mitiempo]

Fuses between the panels and the MPPT controller are not needed. Solar panels are self limiting - they can not produce more current that they are designed to.

A fuse is needed between the controller and the battery in the positive wire - as close to the battery as possible. A shorted battery bank can produce thousands of amps.