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Good morning gents. 

I need some advice on solar panels I have 2 x 285w panels in series on my roof I'm planning to install 2 more after the lock down. Now my problem is I'm only getting around 350w from them in really sunny days. I need to know if I possibly have a problem with direction and tilt. I'm in kwazulu-natal, Richards Bay and they are facing 347°N not sure about the tilt but it's basically the angle of my roof. I have gone through all the connections and everything looks fine.

Any advice would be appreciated. Thanks 

IMG_20200413_063647.jpg

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I’m no expert on angle’s of panels, but would think on a good day peak pv you should be able to get at least 80% from the 2 x 285W panels, you are currently only getting slightly over 50% out of them at peak that sounds a bit low. If wire thickness from panels to inverter is to thin it could cause a volt drop, Also if they are to close to the tiled roof and have no cooling I believe they will loose efficiency.

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On 2020/04/13 at 6:39 AM, Hannes Bester said:

I need to know if I possibly have a problem with direction and tilt

 

Hi

The correct angle as far as I have read up should be about 26 degrees or a little more as you are further South. North facing. I guess wiring of 2mm squared or larger should not cause a problem with a volt drop. 

I am curious how you measured the max to be about 350w.

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Hi

That is correct you should use wire that is 4mm squared or thicker.

 As there are only 2 panels in series that give about 10amps max and about 64volts.

If the wire was 2mm squared the resistance would be about 0.0083ohm/m.

If the wire length was 50m the resistance of the wire would be 0.42ohm. 

The volt drop would be 4.2v which would be (64v-4.2v)= 59.8v. A drop of 6.5% for copper wire.

So it does make a difference. It would only be 2.1volt  3.25% for 4mm squared wire.

If the wire was 2mm squared it still would not make up for the for that large loss.

 

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Oookay, I don't want to be that guy who urinates on batteries, but can I ask about how you mounted that module?

modulemount.jpg.e550fe1ea5f693e8d24305c628c05050.jpg

That looks like two thin angles screwed or riveted to the middle of the module, and I assume somehow to or through the tile? Three reasons I worry about that. First is that it might violate the manufacturers instructions and therefore the warranty. Look in the specification sheet for the proper places to mount it (so-called clamp zones). Second is that a simple screw (teq?) or rivet in that location may work itself loose with wind and weather, and third is that it really should be tied to the purlins below the tiles.

The main concern with PV modules is the lift they create. If a strong wind comes along, will it shear off the brackets, and/or take some tiles with it? I suppose it also depends where you live. Where I live we get 120km/h winds about once a year.

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23 hours ago, Peter Topp said:

Hi

The correct angle as far as I have read up should be about 26 degrees or a little more as you are further South. North facing. I guess wiring of 2mm squared or larger should not cause a problem with a volt drop. 

I am curious how you measured the max to be about 350w.

HI thanks for the reply. 

My inverter displays the pv volts, amps and watts. I used 6mm wire on a distance of 12m. I'm actually really puzzled with the setup. From around 09:00 to 11:00 in the morning it's peaking at around 480w to 510w after that it's between 280w and 350w and there is no shade full sun in days of 37°C. I really don't understand it. I'm actually thinking of replacing the 2 x 285w panels with 4 x 310w panels. 

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