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Solar Power Output Erratic


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As you can see by the screenshots, the Volage on the Solar Panels remains Fairley constant, but the Power and Current are extremely erratic, is this normal - We have 4 Canadian 450w installed for less than a week, so this is all still a learning curve for me and its no point in asking the installer as they will tell you that is working perfectly when it actually might not be

PV Currnet.png

PV Power.png

Pv Volt.png

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Hi,

I may have this completely wrong, so I welcome to be corrected.

Based on my experience the PV Power generation is directly related to the my Power usage, it does not indicate peak possible generation. {in your case 4x450w minus some loss}

As an example. If I am running 100% off solar, and my batteries are full. The PV generation will never show peak possible generation, it will only show what I am using at that point in time, lets say 800watt (yes it also shows little peaks and troughs). If I put the kettle on, I can clearly see the "PV Power" increase on the graph, to example 2800watt and drop again to roughly 800watt when its boiled. 

Three or four time a day my system switches to Battery to cycle and eventually it will start charging again, that is usually when I see the peak performance, because now its using all it can to recharge the battery. After this is drops again.

So in theory, all those little peaks you notice in your data could be your normal up and down usage, like cellphone or laptop charging, but without a bit more context about what you are running (system and load wise), I can only offer my own experience.

Hope that helps.

 

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Something looks badly wrong with those graphs. Perhaps the panels were installed in parallel, instead of series? Power seems to be clipping around 450W. Otherwise, perhaps you have a bad connection somewhere in the solar string, or a defective panel?

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Hi clu, as per the installer they were installed in Series, I will monitor again today by leaving the Input on Grid to see if the graph result is not a negative affect of the usage

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Ok, so here are the readings for the Past 30 Min with Setting on Grid, so In know the Solar is not being used by the inverter and I made a Video of the Actual inverter readings HERE

To me it looks like something is resetting every second

Who agrees that I need to get the installer back here?

PWR1.png

Volt1.png

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Chad, something definitely not right with those graphs. I don't know what it could be?

Hopefully others here will have some insight before you have to call out the installer.

MdF

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As per my Installer : "The panels generate an average of 150-160V dc which tells me the panels are fine and connected correctly, If you want to get a second opinion im happy for you to do so" - So he is not even willing to come and look. I will get an outside person out 

 

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Posted (edited)

Hi @ChadRobinson,

No mention on the flavour/type of inverter you have. If you have a low voltage Axpert type, then something is very wrong, and 150V is too high a input voltage, risking failure. 

On the other hand, a Sunsync or high voltage Axpert type, the input voltage of 150 V is too low to 'wake' up the mppt properly. Then I would add at least 1 more panel in series to raise the voltage, you can safely go S8 or even S9, depending on your panel spec, of course. 

Let us know your inverter type, so the experts can advise accordingly. 

Edited by Sidewinder
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11 hours ago, ChadRobinson said:

What should my Ave Energy Production be in a day with the 4 450w Panels in Series ? I am getting on Ave 1.6Kw a day?

 

With 4 x 450W you should expect about 8,1 Kwh on a good sunny day.

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9 hours ago, Sidewinder said:

Hi @ChadRobinson,

No mention on the flavour/type of inverter you have. If you have a low voltage Axpert type, then something is very wrong, and 150V is too high a input voltage, risking failure. 

On the other hand, a Sunsync or high voltage Axpert type, the input voltage of 150 V is too low to 'wake' up the mppt properly. Then I would add at least 1 more panel in series to raise the voltage, you can safely go S8 or even S9, depending on your panel spec, of course. 

Let us know your inverter type, so the experts can advise accordingly. 

Hi Sidewinder, the Inverter is an RCT Axpert MK4 5.6k- 48V and the MPPT Voltage Range is 120~430Vdc and the Max. PV Array Open Circuit Voltage is 450 Vdc

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Ok Adding to everything Above ... I spoke to another installer and he tells me that the PV Power Reflected by this Inverter is not the Power Produced by the Inverter but rather the "Charging Power" so essential the numbers reflected are indicative of what I am using and not what I am producing 

Right now I feel like a sick person googling their symptoms after a Stomach ache and all Google tells me is that I am going to die ....

My Gut feeling is there is something not right but I am not informed enough to actually know if this is the case.

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1 hour ago, ChadRobinson said:

Ok Adding to everything Above ... I spoke to another installer and he tells me that the PV Power Reflected by this Inverter is not the Power Produced by the Inverter but rather the "Charging Power" so essential the numbers reflected are indicative of what I am using and not what I am producing 

Right now I feel like a sick person googling their symptoms after a Stomach ache and all Google tells me is that I am going to die ....

My Gut feeling is there is something not right but I am not informed enough to actually know if this is the case.

Based on all your graphs there seems to be a problem. The fact that your panels keep on dropping to zero PV is not right.

Also one must ensure you have enough load connected at all times to work out what you should be producing. Also there must be no shading. Further the area of the install needs to be known so that other members can provide the it output based on the weather of a specific day. If you were in Gauteng I can provide details of the maximum you could expect.

As far as the output goes your inverter should have access to the power produced by PV by looking at the volts x amps from the panels on the left hand side of display if you scroll through the values. But pressing the down array about 5 times the values for power used for loads will come up on the right hand side. Not spot on as mine gives the same reading for Watts and VA while the Watts should be quite a bit lower if motors are running like fridges. It does at least help to give an indication

Sorry to see your battles with the system.

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  • 1 month later...

Update - I had another 4 Panels installed which did not solve the problem, also had a 5Kw Lithium battery installed and sold the Gel Batteries ... If the Inverter is on SUB then it still does it, but on SBU it does not ... Especially when there is a load ... The new installer explained that if there is not enough "Draw" on the solar, it will do it. So I turn my Inverter to SBU at 5am, by 10am when I have sufficient Sun the Battery is at about 40% and Solar starts Charging the battery and the panels Generate around 1800w and 6A constantly as they charge ... so it all makes sense

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On 2022/05/18 at 9:47 AM, ChadRobinson said:

What should my Ave Energy Production be in a day with the 4 450w Panels in Series ? I am getting on Ave 1.6Kw a day?

read the wiki on Capacity Factor. I think the utility-scale operators use around 25% for our latitude?longitude?

over a year, spring, summer, autumn, winter, rain, shine, hail etc you should see 4panels x 450W/panel x 24hrs x 25% = (4 x 450 x 6) Wh
 

derate that for panel ageing, shading, air pollution, panel cleanliness, and other effects in your area

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1 hour ago, sahil said:

read the wiki on Capacity Factor. I think the utility-scale operators use around 25% for our latitude?longitude?

over a year, spring, summer, autumn, winter, rain, shine, hail etc you should see 4panels x 450W/panel x 24hrs x 25% = (4 x 450 x 6) Wh
 

derate that for panel ageing, shading, air pollution, panel cleanliness, and other effects in your area

Depending on the area I think getting 6 x PV power per day is pushing it by a big margin. This is firstly if you are using every watt generated. Further even if you do 6 times for an average year round is just far too high except may be in the Northern Cape but it might even be too high for the best part for solar in the country.

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Ya. that might be the figures we use to convince the banks to lend us money :D

you are right about the ideal conditions. every Wh is sold to eskom, the plant is built with optimised geometry on an optimised site, and the panels are cleaned quite regularly (not sure how often, because we also have to respect water consumption)

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