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Goodwe 5048d-es with 20 solar panels. Parallel or series.


Muhammade
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Looking at installing a goodwe 5048d-es with 20 x Canadian 410watt panels. Looking at the voltage I should be able to install max 24 panels, 12 panels per string. Any recommendations on going series vs parallel or a mix of series vs parallel. Note the roof has no shading throughout the day. Distance between the panels and the combiner box is around 30 meters. 

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hi guys,

 

Not to derail the original thread or question, but it actually made me think of something i saw the other day, but perhaps @FixAMess or @Fuenkli or @Jaco de Jongh or @plonkster or @Chris Hobsoncan just clarify something, obviously you need to pair the strings according to max rated wattage etc, as well as the max amps rated for the inverter, when considering the volts though, in the goodwe manual it says the mppt voltage range is from 125-550 volt, then it also says that startup voltage is 150v, and then finally it mentions that the MPPT voltage range for full load is  215-500. SO this is a little confusing to me, does this mean you can size your array to run all the way up to 550volt max, or does it need to stay smaller than 500volt....? I attached a screenshot of the page of the manual i am referring to for all the smarter people out there....

thanx

goodwe es.png

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PV Modules pull down about 15% from their open circuit voltage to the point where they make max power. At the same time, an MPPT will have a maximum input voltage (Voc, aka Voltage open circuit) that should not be exceeded. In most cases, this means that you size the MPPT for a voltage where it rarely spends any time (except early in the morning before it starts up).

In addition to that, MPPTs are DC to DC converters, usually a buck converter, but could by buck-boost in some cases (such as this one). The input and output voltage as well as the frequency and output ripple are parameters you design for, and it is most effective within a certain voltage band.

So basically what these guys have done, is they designed the DC/DC converter to be efficient up to 500V, but allow a max input voltage of up to 550V, and that is perfectly fine since PV modules pull down somewhat in any case, so it ends well.

There is another thing to note though: The MPPTs allow max 11A on the PV side. So if you size your array to 200V or so, you will get max 2000W out of it. You can't put strings in parallel, as that will exceed the current rating (most 300W modules make around 10A already). So to get the full power out of it, you need to put enough modules in series. It's a bit different to other designs where the PV current can be a bit higher.

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Hi Plonkster,

 

I am still a little confused, so will the inverter work better at 500 v oc rather than at 550v? I have 22 candian solar 330watt panels currently setup in two strings of 11 panels each, giving a theoretical value of 501.6v (v oc is 45..6 @ STC, or 41.9 @ NOCT), i have another two panels already mounted, as well as cables in place and everything, but i never connected them because i thought it might cause problems, since my losses was less than what i expected from theoretical values.... so if i understood correctly, my v oc on the panels will be 547.2v oc if i add the extra panel to each string, but it will or should settle around 465 v oc as soon as it heats up, so will it not be better to add the additional panel then, or will this cause the inverter start generating later because it first needs to heat up so that the voltage van drop...?

So will it be better for production to connect these then, or to leave it as is (11 panels per string, v oc at theoretical 501.6v , if i connect one to each string it will push my V on each mppt to VERY close to 550 volt early in the mornings i guess before panels started to heat up....

 

sorry, just want to be sure i understand what you meant... @plonkster

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8 hours ago, Saint said:

So will it be better for production to connect these then, or to leave it as is (11 panels per string, v oc at theoretical 501.6v , if i connect one to each string it will push my V on each mppt to VERY close to 550 volt early in the mornings i guess before panels started to heat up....

I have limited experience with Goodwe, but on two installations I have seen that Goodwe shuts down with PV Overvoltage?/Overcurrent? Alarms (during cloudy seasons) if you exceed 6500 Watt in total. In your case you are already on 7260Whp  and adding 2 additional panels in your case will result in a total Array size of 7920whp.

12 hours ago, FixAMess said:

The 6500W includes the 30% oversize quoted.

I agree with this, 6500 already includes the 30% oversize limit. Adding more might not be wise, but it remains your choice. 

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On 2020/07/21 at 7:30 PM, Muhammade said:

Looking at installing a goodwe 5048d-es with 20 x Canadian 410watt panels. Looking at the voltage I should be able to install max 24 panels, 12 panels per string. Any recommendations on going series vs parallel or a mix of series vs parallel. Note the roof has no shading throughout the day. Distance between the panels and the combiner box is around 30 meters. 

Here is my conclusion and Correct me If I am wrong...

Lets start with the Maximum power point of the 410 watt Canadian solar panel is 39.1V @ 10.49 amp so then we can assume the Maximum power point of 12 panels in series will be 496.2 V @10.49 amp.

Max Voltage the MPPT can handle is 580v and the VOC of a Single panel is 47.6 V  and the VOC of 12 Panels will be 571.2 V within the max voltage range of the MPPT

So the MPPT will try to keep the panels at their maximum power point which is 496.2 V @ 10.49 amps am I correct to assume this?

The voltage full load voltage range of the mppt is between 225 V and 500 V so this means 496.2 V falls close to the upper limit of the MPPT correct me if Iam wrong?

However the total Watts of the solar Array on one MPPT will be 4920 Watt the MPPT will only use 3250 Watt per MPPT as specified by the manufacturer or this is what we can assume.

As long as the array does not exceed the Maximum VOC or open circuit voltage of the MPPT no damage can be caused to the mppt and the the amperage @500 to 550 v of the array does not exceed 11 amp which is specified by the manufacturer which limits you to one string per MPPT again correct me if Iam wrong.

So with this all said I see nothing wrong with this configuration the Down side is when the sun is optimal you wont be able to use more than the rated 6500 watt limited by the inverter yet your system will be able to maintain the Maximum 6500 watt for a longer duration during the sun's cycle so it will start producing max power earlier in the morning and maintain it longer into the afternoon.

Also it will be able to produce more power on overcast days than it would with just 6500 watts of panels.

My two cents.. hope it helps.

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5 hours ago, SteveFury said:

Here is my conclusion and Correct me If I am wrong...

Lets start with the Maximum power point of the 410 watt Canadian solar panel is 39.1V @ 10.49 amp so then we can assume the Maximum power point of 12 panels in series will be 496.2 V @10.49 amp.

Max Voltage the MPPT can handle is 580v and the VOC of a Single panel is 47.6 V  and the VOC of 12 Panels will be 571.2 V within the max voltage range of the MPPT

So the MPPT will try to keep the panels at their maximum power point which is 496.2 V @ 10.49 amps am I correct to assume this?

The voltage full load voltage range of the mppt is between 225 V and 500 V so this means 496.2 V falls close to the upper limit of the MPPT correct me if Iam wrong?

However the total Watts of the solar Array on one MPPT will be 4920 Watt the MPPT will only use 3250 Watt per MPPT as specified by the manufacturer or this is what we can assume.

As long as the array does not exceed the Maximum VOC or open circuit voltage of the MPPT no damage can be caused to the mppt and the the amperage @500 to 550 v of the array does not exceed 11 amp which is specified by the manufacturer which limits you to one string per MPPT again correct me if Iam wrong.

So with this all said I see nothing wrong with this configuration the Down side is when the sun is optimal you wont be able to use more than the rated 6500 watt limited by the inverter yet your system will be able to maintain the Maximum 6500 watt for a longer duration during the sun's cycle so it will start producing max power earlier in the morning and maintain it longer into the afternoon.

Also it will be able to produce more power on overcast days than it would with just 6500 watts of panels.

My two cents.. hope it helps.

Thanks Steve. I believe you are correct. The extra panels are to cover winter season as the we will need to charge 4 x us3000 batteries. So serial it is. 

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