sidaniels avatar image

Solar Controller options?


We are currently looking to install a large solar array to our catamaran and would like to know the most suitable Victron Solar Controller options for our application.

The array is to consist of 10 panels in total. 6x300w panels and 4x270w panels whis are to the specifications shown below..

The thought process is to break the panels into 5 pairs connected in series (3x600w & 2x540w) which will then run to the solar chargers (potentially 5 separate MPPT's), which will intern charge a large 12v lithium battery bank.
Can anyone provide information on the most suitable Charge controllers to achieve this, or if the is a better alternative to running 5 controllers. (I do not which to connect any more than 2 panels in series, to maintain optimum output protection against potential shading of panels)

Any thoughts would be much appreciated. Thanks in advance.

MPPT Controllerssolarsolar sizing
elecspec.png (28.8 KiB)
1 comment
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An interesting problem.

3 solutions.

(1) 3 x 100/50 Mppt. 3 x 300w panels paralleled on 2 controllers, 4 x 270w paralleled on the third controller.

(2) 5 x 100/30 Mppt. 2 paralleled panels per controller.

(3) 2 x 100/50. 3 x 300w panels paralleled each. And 2 x 100/30 Mppt with 2 x 270w panels paralleled each.

Solution 1 is the least cost for Mppt, but losses on the last controller and string fusing cost could be a problem.

Solution 2 is the highest cost for Mppt, some loss from overdimensioned PV array, KISS.

Solution 3 is mid cost for Mppt. Will need array fusing driving total cost up.

2 Answers
JohnC avatar image
JohnC answered ·

Hi S. At 12V, and with that much W, you'll likely be looking at 3x to 5x mppt's at the larger and more expensive end of the range. Can be done, but hang on now, and please pardon me for the 'deviation'.

Depends on your loads, but maybe 48V (or even 24V) would be more suited. If your loads are massive 12V, then ignore me, but if mostly ac, a 48V inverter will be fine. Sure you'll have at least some 12V loads like lights, instruments, even pumps. But a dc > dc converter might deal with those, and if more substantial, even a separate 12V batt charged via an ac box will suffice. I've both those options on my boat, and there's no way I'll return to 12V for the house batts, with less pv than you..

For you @ 48V then, perhaps an array of 5x 100/20_48's would be perfect? Smaller, cheaper, likewise with wires, breakers, etc. right through the system.

Just for you to chew on.. :)

Edit/: Posted before seeing Klim's comment. Which is fine, I've just deviated a little.. :)

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adev avatar image
adev answered ·

Have a good read through this before you decide to mix panels on a given array...

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