Am I Expecting too much from my Solar Panels

[chala]

Originally Posted by noelex 77

I got a peak output of 24.8A.

I find this high do you have MPPT? I would have expected at best no more than 19.8A for 330W and 48.6A for 6 * 135W.

[CSY Man]

I am getting 10+ amp hours out of my 2 X 75 Watt panels on a good day.
55 to 60 amp hours for the day, fixed angle panels, MPPT regulator included.

Your panels are 5.4 times "bigger" and using the above numbers should yield 54 amp hours or 300 amp hours for the day.

(my panels are over 10 years old, not the latest technology and probably have lost some oomph)

[barnakiel]

Originally Posted by noelex 77

I am in Greece , without looking up insolation values I would expect they are simililar to you in france.

You can look them up here. How does it compare then?

http://upload.wikimedia.org/wikipedi...-Europe-en.png


b.

[noelex 77]

Originally Posted by chala

I find this high do you have MPPT? I would have expected at best no more than 19.8A for 330W and 48.6A for 6 * 135W.

The regulator is an Outback 60 which is MPPT. The panels were producing well over 20A for a lot of the day, which is not unusual. I have checked the calibration of the 2 displays I have.
I assumed the 24.8 A was at a reasonably low voltage, but I was surprised to see the peak power was 350w, not bad from nominally 330w panels. It's not often you see power greater than the rating of the solar panel, but it can occur if it's bright, cold and particularly just as the sun peaks out from behind a cloud.

[jeremiason]

We have four 135 watt panels run in series (2x2) to a Blue Sky 60 amp MPPT Solar Controller... The controller is made to accept 36 to 48 volts imput from the panels, which allows you to run panels in series. This causes more output to the batteries.

The four 135 watt panels ares making 30 amps per hour in direct sun...

We have a second bank of three 85 watt panels run in series as well...

The combined output to batteries is about 42 amps per hour in direct sunlight...

There are a number of reasons you are not achieving at least 40 amps per hour...

• One or more panels have slight shade, which effects output
• Your panels are set up in parallel, which would reduce output.
• You wiring is the wrong size for the application... You should check the output wires running from the regulator to your battery and ensure they are at least one size larger than caled for for your paticular length.
• The regulators are not rated for your amount of solar (What size are they)

Good Luck

[noelex 77]

Originally Posted by barnakiel

You can look them up here. How does it compare then?

http://upload.wikimedia.org/wikipedi...-Europe-en.png


b.

The table is for yearly averages and shows the OP is about 15% less in 46.5N Les Sables-d'Olonne, France, but there is more difference in latitude than I had assumed, which in the middle of spring will make more difference, although more in total amp hours rather than peak output.

[noelex 77]

Originally Posted by jeremiason

We have four 135 watt panels run in series (2x2) to a Blue Sky 60 amp MPPT Solar Controller... The controller is made to accept 36 to 48 volts imput from the panels, which allows you to run panels in series. This causes more output to the batteries.

The four 135 watt panels ares making 30 amps per hour in direct sun...

We have a second bank of three 85 watt panels run in series as well...

The combined output to batteries is about 42 amps per hour in direct sunlight...

There are a number of reasons you are not achieving at least 40 amps per hour...

• One or more panels have slight shade, which effects output
• Your panels are set up in parallel, which would reduce output.
• You wiring is the wrong size for the application... You should check the output wires running from the regulator to your battery and ensure they are at least one size larger than caled for for your paticular length.
• The regulators are not rated for your amount of solar (What size are they)

Good Luck

There is a lot of debate about series and parallel connection. I am still not sure which is best, but any difference will be reflected in the output in difficult conditions , such as shade. The maximimum output should be essentially the same for either type of connection.
My panels are connected in parallel, although I hope to do some comparative testing at some stage.*

[jeremiason]

Originally Posted by noelex 77

There is a lot of debate about series and parallel connection. I am still not sure which is best, but any difference will be reflected in the output in difficult conditions , such as shade. The maximimum output should be essentially the same for either type of connection.
My panels are connected in parallel, although I hope to do some comparative testing at some stage.*

Actually, I ran my panels in Parallel first and then in series and found that with this particular controller I was outputing almost 30% more power in series... That settled the debate for me.

[noelex 77]

Originally Posted by jeremiason

Actually, I ran my panels in Parallel first and then in series and found that with this particular controller I was outputing almost 30% more power in series... That settled the debate for me.

That's a big improvement. Can you supply any more details.it has been on my list to do some comparritive testing, but in my case it will take some time to change them over, which is going to make it difficult to control the variables and come to valid conclusions.

[bluemana]

Update
Thanks again for advice especially "Handy Bob's Blog". It is rather long but full of essential information from an experienced installer and conveyed in a way that is easily understood.
The installer has agreed to rewire the panels using larger diameter wire as the original was way undersize. Especially as instead of running 2 banks of 3 panels, it ended up 4 and 2 because the runs were easier. Also wires from the controller to battery bank were under size.
I would like to replace the 2 controllers with 1 MPPT controller but the price in France is more than double.
Also I am not sure if it would accept 2 different power banks (4x2) with different wire runs. Does anyone have an opinion?

[noelex 77]

Originally Posted by bluemana

Update
Thanks again for advice especially "Handy Bob's Blog". It is rather long but full of essential information from an experienced installer and conveyed in a way that is easily understood.
The installer has agreed to rewire the panels using larger diameter wire as the original was way undersize. Especially as instead of running 2 banks of 3 panels, it ended up 4 and 2 because the runs were easier. Also wires from the controller to battery bank were under size.
I would like to replace the 2 controllers with 1 MPPT controller but the price in France is more than double.
Also I am not sure if it would accept 2 different power banks (4x2) with different wire runs. Does anyone have an opinion?

I am not quite sure what you mean by 4x2, when as I understand you have 6 panels, but you can wire up the panels in a series, parallel or any combination. The voltage must be the same for each bank, and ideally the panels should be identical and experiencing the same conditions.
A common way to wire up 6 panels is by connecting banks of 2 panels in series (24v) and then connecting the 3 banks in parallel to the controller. Ideally the wire runs should be a similar length, but it's not critical.
I always try and support the local economy, but sometimes the price difference is too much. Ordering from within the EU is generally easy, but from the USA vat problems complicate things.
An Outback 80 would be a good choice. I ordered one from the UK a year ago and got great service. PM me if you want details, but tomorrow I am sailing for some deserted islands and may not have Internet for a while.

[bluemana]

Not sure how to PM as yet but to clarify:
4 panels linked (not sure if series or parallel) plus 2 panels linked.
They didn't do 3 and 3 because it was harder to run the wire.
If the panels didn't improve a company was willing to send a wind generator to Gibraltar thus not having to charge VAT.
It may be possible also, to get a MPPT controller sent there.

[hellosailor]

blue-
I think you would have two choices. Link the 4 panels in series/parallel, so they are each two panels in parallel, then combine the two assemblies in series, making one larger array (all 4 panels) putting out a nominal 24 volts, if your controller will handle that. (And if you are getting a new controller, plan for that.)
Similarly, take the other two panels and put them in series, to provide another 24-volt array. If all 4 panels are the same wattage, same maker, the MPPT point on them should be the same and an MPPT controller should be able to see both arrays (the 4 and the 2) joined in parallel as one single 24-volt input.

Why 24-volt? Because your wiring losses will be lower, and the MPPT controller efficiency will be somewhat slightly higher. Series and parallel each have their pros and cons and I suspect that given you installation and problems with wiring losses, a combination system may work out better for you.

You might also ask the installer what wire sizes he is using, and quietly look up the losses they will have to make sure he is doing it correctly, not just another compromise, this time around.

[willardj]

Originally Posted by bluemana

Update
Thanks again for advice especially "Handy Bob's Blog". It is rather long but full of essential information from an experienced installer and conveyed in a way that is easily understood.
The installer has agreed to rewire the panels using larger diameter wire as the original was way undersize. Especially as instead of running 2 banks of 3 panels, it ended up 4 and 2 because the runs were easier. Also wires from the controller to battery bank were under size.
I would like to replace the 2 controllers with 1 MPPT controller but the price in France is more than double.
Also I am not sure if it would accept 2 different power banks (4x2) with different wire runs. Does anyone have an opinion?

Np. I came across Handy Bobs blog a few weeks ago. When I started thinking I wanted to put a panel on my boat. Lots of good info and yes it is quite long, but still worth the read. Good luck on your install.