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Colin

Multi strings

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No, despite common opinion t doesn't.

In the morning production is grater than before on the 15 strings but in the afternoon production drops to the same level of the  other two arrays

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The wizard
24 minutes ago, ibiza said:

No, despite common opinion t doesn't.

In the morning production is grater than before on the 15 strings but in the afternoon production drops to the same level of the  other two arrays

Hi Ibiza are you able to compare voltage of your multi oriented array with one of your regular arrays?

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The wizard

That is not a large difference.

Could I ask you to look again this afternoon.

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the notorious
14 hours ago, plonkster said:

To be fair, little three-panel strings are unlikely to really get dangerous

Reminds me of a certain 2 x 200w panels setup that had an issue ito a "installer" (read poepol) taking them from parallel to series.

In his defence, it was blerrie high on the very edge of a 2nd story roof, 11-12pm on a very hot summers Saturday, that said "installer" got the stupid bee in his stupid bonnet because a certain Mr @Chris Hobson pointed out a small correction ito the max watts between 12v vs 24v ito series vs parallel.

Said poepol was a small poepol even before started off being a even bigger poepol.

Issue was picked up quick, yes, but the damage was done pretty fast he will attest, as it takes wee bit of time getting up and down said roof.

The diodes on one panel melted into oblivion, as did part of the casing they where in. Panel was so hot it nearly gave blisters.

Panel itself was unscathed, not sure about the lifespan or for how long it will still work.

Nor if it would have started burning if it was not picked up that quick.

The diodes are now top of the range, before they where just ... there.

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The wizard
4 minutes ago, The Terrible Triplett said:

.......because a certain Mr @Chris Hobson pointed out a small correction ito the max watts between 12v vs 24v ito series vs parallel.

I will forever be know as the pyrotechnic adviser. Bellville's fire department are still looking for me to take a statement.

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1 hour ago, Chris Hobson said:

That is not a large difference.

Could I ask you to look again this afternoon.

No, it is not but difference come from 3 panels only against other 12 which are in the shade at the time I took the voltage.

I will post the afternoon voltage

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The wizard

I am more interested  in how much the 3 retard the 12 than the other way around. Early morning I would expect high voltages (close to VOC ) when the 12 are running voltages will be lower and how much do the three influence voltages when the system is up and running. 

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I will then disconnect 12 tomorrow morning and leave 3 east facing panels running and tell you the voltage of both of them.

You must take in account the weather that was very cloudy whole day today but forecast for tomorrow morning is party cloudy so we might have a chance to see better reading ;).

'how much do the three influence voltages when the system is up and running. ''

I can tell you the power the three produce in the morning is at lease double if not more then the other 12. I was not paying to much attention on the voltage as I did to the power produced by the three.

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The wizard

don

13 minutes ago, ibiza said:

I will then disconnect 12 tomorrow morning and leave 3 east facing panels running and tell you the voltage of both of them.

Don't disconnect - just compare the voltage of your 15 panel array with your 12 panel array at about 12 and again at about 15h30. If you disconnect then it is like a normal array.

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I am not sure I understand you. If I leave only three east facing panels running I can compare to  12 panels of another array and see how east facing panels are efficient. Do you agree with that or not?

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The wizard
11 hours ago, ibiza said:

I am not sure I understand you. If I leave only three east facing panels running I can compare to  12 panels of another array and see how east facing panels are efficient. Do you agree with that or not?

As I am not familiar with your setup I might have it all screwed up. You have 3 Axperts and therefore 3 arrays. As an experiment one of those arrays is split with a fifth of the panels facing East. Can one compare this to one of the other arrays or is there not another array that has the same orientation as the bulk of the panels in the first array?

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21 hours ago, Chris Hobson said:

don

Don't disconnect - just compare the voltage of your 15 panel array with your 12 panel array at about 12 and again at about 15h30. If you disconnect then it is like a normal array.

Now at 7:00  15 panels array is producing 572w at 101.9v

                        12 panels array is producing  209w at 83v

12:00              15 panels array is producing  2209w at 84v

                         12 panels array is producing  2371w at 74v

I will edit this post at  and at 15:30

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MR PENN
5 hours ago, Chris Hobson said:

As I am not familiar with your setup I might have it all screwed up. You have 3 Axperts and therefore 3 arrays. As an experiment one of those arrays is split with a fifth of the panels facing East. Can one compare this to one of the other arrays or is there not another array that has the same orientation as the bulk of the panels in the first array?

 

5 hours ago, ibiza said:

Yes I have 3 Axperts. All of them has 12x 250W arrays plus to one of them I added 3 same type of panels that faces east.

What interests me is WHY were you both at your PC's at 3am to have this conversation?:lol:

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The wizard
23 hours ago, pilotfish said:

 

What interests me is WHY were you both at your PC's at 3am to have this conversation?:lol:

:lol::lol:

My wife is in hospital for tests and I

am in a strange place with a strange bed. Put my son to bed and went to sleep shortly afterwards but man cities are noisy.

On 4/10/2018 at 7:11 AM, ibiza said:

Now at 7:00  15 panels array is producing 572w at 101.9v

                        12 panels array is producing  209w at 83v

12:00              15 panels array is producing  2209w at 84v

                         12 panels array is producing  2371w at 74v

The losses caused by the disparate array seems more than made up by the early morning production.  This is valuable information and monitoring for a couple of days would give a clearer picture.

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MR PENN
26 minutes ago, Chris Hobson said:

My wife is in hospital for tests

I hope nothing serious and all goes well.

27 minutes ago, Chris Hobson said:

This is valuable information and monitoring for a couple of days would give a clearer picture.

The test is very interesting and the results from the disparate string are better than I expected, but there may be a problem with the test method;

I have noticed with my 2 parallel Axperts that while at full PV capacity their PV output is identical (which I assume is the max output from the identical arrays), but when output is being restricted by the load then the Master is often 5-10% lower than the slave. So results may be impacted by the MPPT while not at full PV capacity.

In order to avoid the above it would be necessary to bang on some heavy loads before recording test data to ensure that the arrays are being fully driven, that way we would know that the MPPT's are pulling everything available from the 3 arrays.

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21 minutes ago, pilotfish said:

I hope nothing serious and all goes well.

The test is very interesting and the results from the disparate string are better than I expected, but there may be a problem with the test method;

I have noticed with my 2 parallel Axperts that while at full PV capacity their PV output is identical (which I assume is the max output from the identical arrays), but when output is being restricted by the load then the Master is often 5-10% lower than the slave. So results may be impacted by the MPPT while not at full PV capacity.

In order to avoid the above it would be necessary to bang on some heavy loads before recording test data to ensure that the arrays are being fully driven, that way we would know that the MPPT's are pulling everything available from the 3 arrays.

That's what the slaves are for, aren't they?

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The wizard
22 minutes ago, pilotfish said:

I hope nothing serious and all goes well.

It does not appear so but so far results cannot explain her symptoms.

20 minutes ago, pilotfish said:

I have noticed with my 2 parallel Axperts that while at full PV capacity their PV output is identical (which I assume is the max output from the identical arrays), but when output is being restricted by the load then the Master is often 5-10% lower than the slave. So results may be impacted by the MPPT while not at full PV capacity.

In order to avoid the above it would be necessary to bang on some heavy loads before recording test data to ensure that the arrays are being fully driven, that way we would know that the MPPT's are pulling everything available from the 3 arrays.

Something I had not thought of - your solution is elegant.

 

 

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1 hour ago, Chris Hobson said:

:lol::lol:

My wife is in hospital for tests and I

am in a strange place with a strange bed. Put my son to bed and went to sleep shortly afterwards but man cities are noisy.

The losses caused by the disparate array seems more than made up by the early morning production.  This is valuable information and monitoring for a couple of days would give a clearer picture.

I am sorry for the joke, I did not know about your wife.

My reason to reply to the post starter's question was to tell that there is no issue with multi orientation of panels. At least I do not have any problem.

My aim was to see  how much power I can count on putting whole Array to face east and another to face west cause I am  lacking  power in the early morning and in the late afternoon. My first idea was to build a solar tracker which is extremely simple to do but decided to erect a new roof on the part of the house where is a flat roof now and where all the panels are installed . The new one will face east-west with enough space to accommodate 12+12 panels.

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MR PENN
17 minutes ago, ibiza said:

I am sorry for the joke, I did not know about your wife.

I am sure that Chris is aware that the joke didn't refer to his wife.

17 minutes ago, ibiza said:

The new one will face east-west with enough space to accommodate 12+12 panels.

It would still be very valuable if you could carry out the early morning, midday, mid afternoon test on your current setup while ensuring that all arrays are full capacity - it would settle a lot of assumptions that have been made over a long period, my own included.

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The wizard
1 hour ago, ibiza said:

I am sorry for the joke, I did not know about your wife.

No offence meant and no offence  taken

1 hour ago, ibiza said:

The new one will face east-west with enough space to accommodate 12+12 panels.

Oooh I like East-West arrays. Just completed a 25kWp East-West array.

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