Can you suggest wire size?

[dileepa]

I would comfortably use a 4mm cable if I connect these panels in series.
For parallel configuration(2S2P) should the 4mm cable still fit? Should I increase the gauge since the current goes up?

Panel config
535w
Voc - 49.45v
Vmp - 41.47v
Isc - 13.79A
Imp - 12.9A

thank you ?

 

[Leeds]

In 2s 2p you'll need a charge controller that can accept 150v on cold days.

For current you'll need to account for 28A on the combined wires. 14A is the max current on the non-combined strings.

I'd put a 30a breaker on the series and use 4awg if you went that setup.

 

[Danke]

4mm cable is 6 AWG, so more than adequate

Specifications*:

Size: 10 AWG
Number of Strands: 7 or 19
Insulation Thickness (Conductor): 0.065 inches
Outside Diameter: 0.280 inches
Weight: 0.057 lbs per ft
Allowable Ampacity: 40 Amps at 90°C Wet/Dry

Size: 8 Gauge
Number of Strands: 19
Insulation Thickness (Conductor): 0.075 inches
Outside Diameter: 0.292 inches
Weight: 0.080 lbs per ft
Allowable Ampacity: 55 Amps at 90°C Wet/Dry

Solar PV Wire (Photovoltaic) | WireAndCableYourWay.com

We stock Solar Photovoltaic (PV) Wire in a variety of gauge sizes. Most of our SKUs are sold by the foot and in bulk. Order today for fast shipping!

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[LeoThomson]

I would comfortably use a 4mm cable if I connect these panels in series.
For parallel configuration(2S2P) should the 4mm cable still fit? Should I increase the gauge since the current goes up?

Panel config
535w
Voc - 49.45v
Vmp - 41.47v
Isc - 13.79A
Imp - 12.9A

4 mm is fine, just make sure it is is UV rated if used outside and/or can cope with vibrations if you use it in a vehicle.

Cable Size & Current Rating Chart

Cross Sectional Area of Conductor (mm2)Approximate Overall Diameter of Insulated Cable (mm)Current RatingSingle Phase (Amps)Three Phase...

www.spwales.com

 

[Leeds]

It's the roughly 70 feet of total transmission (20m) that makes me want to go bigger than the panel sized wires quoted above.

Wire Sizing Chart for 12V/24V/48V DC Systems - DIY Solar Resources

Information on wire sizing and a universal AWG/mm2 wire sizing chart to help in designing a 12V, 24V, or 48V DC renewable energy system.

www.altestore.com

 

[OzSolar]

To meet code in the US, I first size the wire to Isc x 1.56.

For voltage drop calculations I use NOCT which generally speaking is about Imp 80% of Imp. Keep in mind your array will spend most of it's life at conditions less than NOCT. Once you've sized to meet code power losses from voltage drop is rarely a consideration in my experience.

 

[brum]

With 70 feet of 10AWG wires, you will have close to 2% losses when the current is at max levels. If the current goes to half of the max (15A) your losses are less than 1%. I would go with the standard 10AWG copper PV wires.

 

[dileepa]

Thank you for your thoughts. I really appreciate it. Looks like 6AWG/4mm will be adequate for my configuration.

 

[brum]

Wires are measured in cross-section. 6AWG is matched to the 16mm2 wire. The 4mm is not something you would usually look at. This is a pretty heavy wire. And AFAIK there is no standard PV wire with that size. The common options are 4mm2, 6mm2, or 10mm2 (the last one is a bit exotic).

Check the price difference between 6mm2 and 10mm2 and if it justifies roughly 0.5% more power production - go for it.

And to be more on the same side - there is no perfect match between mm2 and AWG wires, but the commonly accepted one for PV wires is:
6 AWG = 16mm2 ~ 0.4% losses (exotic, I've not seen such being offered around, only at remote online stores)
8 AWG = 10mm2 ~ 0.6% losses (again exotic, but can be found around)
10 AWG = 6mm2 ~1% losses (common)
12 AWG = 4mm2 ~1.5% losses (common)

These are the average losses, not the highest ones. But these are what you should be looking at.