Solar Performance in the Med

[stevensuf]

It is nothing to do with being further north, you get much more sun hours in the med and the suns angle at this time of year is very high, semi flexible panels suffer greatly from heating issues with no air gap underneath, though the panels do not look like flexible ones, i suggest hooking one direct to the battery and measuring the current , if you have the ability to do so, also far better to run them in parallel than series with shading issues. just now if no shade you should be easily getting 60-80 percent of their rated power around lunch time when the sun is highest.

[noelex 77]

Originally Posted by mikedefieslife

I get about 200w at a time max from 4 120w panels and 80-100 from two 110w panels together.

Mike, if you mean the maximum output you have seen from 480w of panels is 200w and the maximum output you have seen from 220w of panels is 80-100w, these are very poor numbers. This indicates something is wrong.

The maximum output of the solar panel array is not a very important number in determining the average power produced, but it is a very significant indicator of the health of your solar system. In reasonably sunny locations such as the Med, the maximum production should be close to the rating of the panels.

In other words, 480w of panels should briefly on occasions be producing 480w or very close to this amount.

[Paradoxus]

Originally Posted by Paradoxus

One obvious answer is that you are further north.

Having said that, the drop in output could also be due to panel damage. It seems to me that they could flex in their position, which over time would lead to damage. Also, is it likely that someone stepped on them?

[NPCampbell]

Is there any shading on your cells whatsoever? A single shaded cell can kill most of your output on your panel depending on the number of bypass diodes that the panel incorporates.

[lawrence_craig]

Here is 1 x 150W panel unshadowed at midday in Croatia.

[noelex 77]

Originally Posted by lawrence_craig

Here is 1 x 150W panel unshadowed at midday in Croatia.

Attachment 198415

The very low panel voltage suggests all is not well with that solar panel, although it is not impossible that this is bad connection.

It is not likely to be the solar regulator mis-tracking as the current should be higher at this low voltage even if that was occuring.

The next step is to disconect the panel and test the short circuit current and the open panel voltage. Google should show you how. You only need a simple multimeter for these tests.

[stevensuf]

Originally Posted by lawrence_craig

Here is 1 x 150W panel unshadowed at midday in Croatia.

Attachment 198415

Are your batteries charged and it is into float mode? a 150w panel should be producing at least 100w at lunch time just now in croatia *unshaded.



I lived in the med and the Caribbean with 320w of panels, in the summer
i would get much more in the med than in the Caribbean, normally low 20amps max around 280w, but 15+ amps much of the day. Something is wrong.


Just now i live in Portugal on land and my house array, which at the moment is flat produces around 1650w out of 2100w rating at peak times and 1000w+ from around 930am till nearly 5pm, 37 degrees north.

[StuM]

Originally Posted by stevensuf

Are your batteries charged and it is into float mode? a 150w panel should be producing at least 100w at lunch time just now in croatia *unshaded.

It looks as thought the batteries are badly depleted. The bottom panel says Bulk and 12V


There is definitely something wrong there with only 25 W from a 150 W unshaded panel

[kas_1611]

Originally Posted by Stewie1

You are further north from the equator. In short the sun is less overhead.

Strictly speaking not completely correct. At the Summer Solstice the sun is directly overhead at the Tropic of Cancer, 23 1/5ºN so the angle of incidence at the Equator is actually identical as it is at 46ºN which is a pretty Mediterranean latitude. So on this date Split in Croatia is receiving pretty much the same solar insolation as the Equator.

In the Caribbean though the sun is pretty much overhead at midday all summer as we are only talking about 5ºN to 23ºN as the sun moves through the region from March to September. That's the critical difference with the incoming solar insolation in the Caribbean and Med. The sun is never directly overhead in the Med.

[sailah]

I'm in Massachusetts. Full sun right now on a 100W panel and I'm getting 69W, absorption, at 2:20 in afternoon. Panel is not at right angles to sun. Victron BlueSolar 75/10.

[CatNewBee]

The sun rises on the east, goes through the south and sets in the west, when sailing or anchoring, there will be some shading from lines, mast, boom etc, this reduces the solar output significantly.

I would make sure, there is no shade and the panel is clean, then measure the current with a clamp Ammeter, make sure the battery is not full, so the controller is in bulk and the battery accepts current, or run a high demand load while checking the output. Very often the battery is in absorption or float, and the solar simply idles at low output.

[sailorboy1]

Originally Posted by lawrence_craig

Here is 1 x 150W panel unshadowed at midday in Croatia.

Attachment 198415

to me that looks at either a wire connection problem from the controller to the batteries or a controller issue

I would start by rebooting the controller

[lawrence_craig]

Originally Posted by sailorboy1

to me that looks at either a wire connection problem from the controller to the batteries or a controller issue



I would start by rebooting the controller

So I did some further tests. At midday in unshaded sun, the solar array is giving out 19V (multimeter to the connections).

However when I connect it to the regulator, the voltage drops to 13-15v.

It’s a Victron SmartSolat MPPT 75/15. It’s only 9 months old.

I have removed and rewired the connectors but getting the same result.

Batteries when testing this are at 30-40% SOC. (I know they shouldn’t be that low but I am about to replace I think).

[CatNewBee]

Originally Posted by lawrence_craig

So I did some further tests. At midday in unshaded sun, the solar array is giving out 19V (multimeter to the connections).

However when I connect it to the regulator, the voltage drops to 13-15v.

It’s a Victron SmartSolat MPPT 75/15. It’s only 9 months old.

I have removed and rewired the connectors but getting the same result.

Batteries when testing this are at 30-40% SOC. (I know they shouldn’t be that low but I am about to replace I think).

That's the way MPPT works, it puts load on tbe panels dragging voltage down and amps up until it finds the Maximum Power Point,

what MPPT means, maximum power point tracking.

So all good, working as expected. Measure the current going to the battery and calculate the power P=V*I where V equals 13..15V and I equals the current you measure.

[ReneJK]

we dont see a large difference in the Med vs Carib ?

on avg 2.9kWh per day from our 670Wp panels in each area anchored (Cape Verdes to Trinidad we saw less , then up again from Grenada north)

since you have (semi) flex panels I would suspect them first , next the wiring