This was on the 5th of November.

On 2021/10/18 at 9:28 PM, PowerUser said:

@YellowTapemeasure I still haven't gotten anything yet. I'm just looking at optimum string sizes and learning how to calculate them properly, so I can compare various options. I created an Excel spreadsheet with the formulas from your link and now I can easily compare options. Here is for example 2 options for JA Solar from the PowerForum store:

For the calculation, I used minimum possible temperature for Randburg -5deg C. The minimum, I could find on record for the past 10 years was -4 deg C. However, that is still very conservative value, as it's probably measured at 4AM or 5AM in winter, when the sun is not shining. We should be looking at minimum temp when the sun is out but doubt, I will find a record like that.

Obviously, the above is only based on the electrical parameters, assuming roof space is not an issue.

There is no voltage drop in the cables accounted in the calculation. Not sure if that will be of any significance for less than 20m cable lengths.

Which option do you guys say would be better? I think, ignoring the cost, the 540W are closer to the half DC PV input power of 6500W/2 = 3250. I'm thinking that because of the Maximum theoretical power by max string at NOCT.

 

Hi there

How would you calculate the max string size using The 455 JA Solar panels also with 2X Sunsynk inverters. I have 20 Panels. 

I am in Upington record low i think is like -2 😊😂...

Edited December 4, 20214 yr by deserthogtac

Hi, silly question. is it possible to connect a 200v kestrel turbine in series with a few panels into a single sunsynk inverter mmpt input?

15 hours ago, Solar_cpt said:

Hi, silly question. is it possible to connect a 200v kestrel turbine in series with a few panels into a single sunsynk inverter mmpt input?

Turbine should always run through it's own charge controller to battery. I think the midnight classic is the right one then you must add the dump load ... The kestrel is not braked so must have dump load. Except if it is the 3.5 kW.

Let me know also how it went !

 

15 hours ago, Solar_cpt said:

Hi, silly question. is it possible to connect a 200v kestrel turbine in series with a few panels into a single sunsynk inverter mmpt input?

I'd rather hook it up to the Aux port.

Hi All, I want to buy panels for my 5kW SunSynk. There is very little stock. All I can find at a good price are the Canadian Solar 550W Super High Power Mono PERC. Will that work on the 5kW SunSynk? Or is the amps too high? See screenshot of datasheet attached.

 

3 minutes ago, Gerrit123 said:

Hi All, I want to buy panels for my 5kW SunSynk. There is very little stock. All I can find at a good price are the Canadian Solar 550W Super High Power Mono PERC. Will that work on the 5kW SunSynk? Or is the amps too high? See screenshot of datasheet attached.

 

They will work - the Amps MIGHT get clipped on certain days but they will work. What you need to keep an eye on is the VOC - which is 49.6 - each MPPT can take a max voltage of 425v so 49.6*8 = 396v is your max number of panels

For Voc the maximum is 500V so one can go to a max of 9 panels. Under normal max power conditions the Vmp will still be under 425V for the MPPT. 

If you want to max out the inverter rating the 2 strings of 6 seems the way to go. 8 or 9 in one string means one cannot just add a few more on MPPT2.

Edited March 1, 20233 yr by Scorp007

On 2023/02/27 at 9:20 AM, Gerrit123 said:

Hi All, I want to buy panels for my 5kW SunSynk. There is very little stock. All I can find at a good price are the Canadian Solar 550W Super High Power Mono PERC. Will that work on the 5kW SunSynk? Or is the amps too high? See screenshot of datasheet attached.

 

I have a friend with those panels on his 8KW sunsynk. I have seen them very regularly produce between 13-16.5 A so i would not put them on the 5Kw inverter as you wil definately be maxing out the amps lots of the time . This means you lose out on lots of power .

2 hours ago, Nexuss said:

I have seen them very regularly produce between 13-16.5 A

The Ioc of that panel seems 14A, is it normal for this to be exceeded during regular use? I've specc'd 15A fuses on the PV side on my JA (also Isc 14A, 550W panels).

But either way, if the SunSynk 5KW has a MPPT max of 11A then these panels will provide too much current (and be clipped) - that said, SunSynk website is notoriously unreliable for specs, eg the 8KW inverter has 22A+22A for the PV input, yet website still says 18A. Perhaps in reality the 5KW also has a much higher PV input amp rating. 

12 minutes ago, Kalahari Cruiser said:

The Ioc of that panel seems 14A, is it normal for this to be exceeded during regular use? I've specc'd 15A fuses on the PV side on my JA (also Isc 14A, 550W panels).

But either way, if the SunSynk 5KW has a MPPT max of 11A then these panels will provide too much current (and be clipped) - that said, SunSynk website is notoriously unreliable for specs, eg the 8KW inverter has 22A+22A for the PV input, yet website still says 18A. Perhaps in reality the 5KW also has a much higher PV input amp rating. 

I am not sure exactly how normal it is but that is whats happening . On my 455W JA panels i also see 12,2A +- semi regularly . For that reason i wouldn't go much higher than 455W panels . I would definitely replace those fuses with 20A ones. The 5kw sunsynk has 13 Amp mppt's and the 8kw has 20Amp mppt's.

Edited March 1, 20233 yr by Nexuss

Interesting! Thanks, yes seems like I'll have to increase those fuse sizes then (based on previous advise I sourced 15A for rated Isc 14 PV input from my JA 550Ws). Perhaps they offer some leeway though, i.e. break after sustained excess? Anyway, will keep in mind. 

Edit: have now also read (albeit a US site) that on the PV input side, fuses should be specc'd 25% above Isc... that would take 14A Isc to 17.5. On a SA site I read a recommendation of a 20% oversize, and then to use the next available size. In any case, 20A would still within the inverter's MPPT spec, and I only have one string per MPPT...

The 8KW Sunsynk is 22A+22A on the MPPTs. 

Edited March 1, 20233 yr by Kalahari Cruiser

8 minutes ago, Kalahari Cruiser said:

Interesting! Thanks, yes seems like I'll have to increase those fuse sizes then (based on previous advise I sourced 15A for rated Isc 14 PV input from my JA 550Ws). Perhaps they offer some leeway though, i.e. break after sustained excess? Anyway, will keep in mind. 

Edit: have now also read (albeit a US site) that on the PV input side, fuses should be specc'd 25% above Isc... that would take 14A Isc to 17.5. In any case, 20A would still within the inverter's MPPT spec, and I only have one string per MPPT...

The 8KW Sunsynk is 22A+22A on the MPPTs. 

Yea the formula is  Iscx1,3 according to what i remember from SANS 10142. The 8kw should have 22A mppt's yes but some users here reported maxing out at 20 so it would be nice to see if they actually can do 22A now ..

On 2023/03/01 at 6:29 AM, Scorp007 said:

For Voc the maximum is 500V so one can go to a max of 9 panels. Under normal max power conditions the Vmp will still be under 425V for the MPPT. 

If you want to max out the inverter rating the 2 strings of 6 seems the way to go. 8 or 9 in one string means one cannot just add a few more on MPPT2.

I have two strings of 6 CS 545Watt panels on a deye 5.5kW inverter and it works great. Total max is then 6540Watts, very close to the max 6600Watt of the inverter. There are some losses in the cables however, but anyway.

Edited March 23, 20233 yr by HendrikBigChief

In case it helps I have the identical inverter from Deye and have 2 strings of 8 x 545W = 8.72kW panels in series and it works without problems, use the biggest serial you can has long you don't go over voltage, I started with a string of 6 panels and after expand to 8 I got 2 more hours of production.

This inverter has de DC temperature a bit high and it brings some problems at the max solar power of 6500W in my case even with a fan it goes 50ºC over ambient temperature, what I have done from start was to put a 14cm fan on top of it in the left side over the cylindrical radiator and to reduce the temperature I limit the battery charge first to 75A and now I'm testing 85A, when ambient temperature increase I will probably go back to 75A or even lower.

DC temp is the temperature of the internal transformer, the brand recommend to limit the charge to 90A.

AC temp is the temperature of the case of the inverter.

Unless you have sun and negative temperatures don't worry much with voltage, the MPPT keep it in control, I would worry more with max A of panels.

my graphs the V and A are of string 1 and P the sum of string 1 + 2 with the 8.72kW panels

 

On 2023/04/24 at 10:14 PM, Delphinus said:

In case it helps I have the identical inverter from Deye and have 2 strings of 8 x 545W = 8.72kW panels in series and it works without problems, use the biggest serial you can has long you don't go over voltage, I started with a string of 6 panels and after expand to 8 I got 2 more hours of production.

This inverter has de DC temperature a bit high and it brings some problems at the max solar power of 6500W in my case even with a fan it goes 50ºC over ambient temperature, what I have done from start was to put a 14cm fan on top of it in the left side over the cylindrical radiator and to reduce the temperature I limit the battery charge first to 75A and now I'm testing 85A, when ambient temperature increase I will probably go back to 75A or even lower.

DC temp is the temperature of the internal transformer, the brand recommend to limit the charge to 90A.

AC temp is the temperature of the case of the inverter.

Unless you have sun and negative temperatures don't worry much with voltage, the MPPT keep it in control, I would worry more with max A of panels.

my graphs the V and A are of string 1 and P the sum of string 1 + 2 with the 8.72kW panels

 

Thank you for your info, a real person widely explained installation example is so much appreciated!

I will be installing Pv on 6k Inverter which is similar to 5K, same DC, just more PV and AC power. And came to conclusion of you are writing of

I want to install 8x545 Longi solar (12.97A 49Voc STC) in my calculations even with 50 degree shift (from 20c temp to -30c) i will get posiible more 7 volts so im in range of 500v (8x (49+7)= 448V maximum

And in normal condition 41x8= 328volts ( im seeing same voltages at yours at around 300-360)

My question is how about the Amp current, Inverter maximum is 13A,

My chosen solar panel is Isc 12.97A and Imp is way higher 13.78 - Is there any worries about that, or i should only worry about Voc overvoltage configuring the strings ?

 

I made a calculation in Sol-Ark calc and used their 5k Inverter 8+8 panels and worried about Isc Min Max

Edited April 28, 20233 yr by Denveronly

52 minutes ago, Denveronly said:

My chosen solar panel is 12.97A( with a temperature coefficient Isc is higher i guess on colder weather). - Is there any worries about that, or i should only worry about Voc overvoltage configuring the strings

You don't have to worry about Isc and I am not aware that Imp fluctuates significantly with temperature. You should, however, be concerned about the quality of your inverter. Some will clip and cut back when they overheat, some will melt. 

1 hour ago, frivan said:

You don't have to worry about Isc and I am not aware that Imp fluctuates significantly with temperature. You should, however, be concerned about the quality of your inverter. Some will clip and cut back when they overheat, some will melt. 

Clipping means turning off power production and turning on when there is less sun? (sorry thats my first PV field, can ask dumb questions)

My Deye (sunsynk) inverter is heating DC chip to 70C degree on battery charge, so i will be installing fans to cool him down, this will also help at solar production cooling

In other case i have 2nd deye 6k (they share one bus battery bar) , so i will just hook one string on that one. The question - is that a good choice 8 panels with those specs on 6k inverter

Edited April 28, 20233 yr by Denveronly

3 minutes ago, Denveronly said:

Clipping means turning off power production and turning on when there is less sun?

With clipping I meant limiting. The Deye/Sunsynk inverters do this. Even though parallel strings of your panels could give 26A, the MPPT will not draw more than the channel rating, 13A or there about on the common 5kW inverters.

15 minutes ago, frivan said:

With clipping I meant limiting. The Deye/Sunsynk inverters do this. Even though parallel strings of your panels could give 26A, the MPPT will not draw more than the channel rating, 13A or there about on the common 5kW inverters.

Thanks for the explanation mate, 

So Amperage is not a big deal, Clipping will reduce production but production will not stop.

Cooling the radiator- im on it already will be installing 2x120mm fans in the bottom or top

The main thing is not to exceed Voltages and they look good for me.

What is your thought. My String setup would be fine? 8+8 panels with 540 panels with specs i gave on top?

 

 

Edited April 28, 20233 yr by Denveronly

7 minutes ago, Denveronly said:

My String setup would be fine?

I missed which inverter you will be installing. But assuming 500V max on the PV input you will be fine. The results you calculated shows that the voltage fluctuates more with temperature than current. Your accent sounds Australian but your calculations go down to -30°C... where are you located?

Sorry, 6kW Deye... I assume it is latest ones. According to that spec sheet 500V is the PV max and you will get max power above 300V for Vmp. 8+8 will work well.

1 hour ago, frivan said:

I missed which inverter you will be installing. But assuming 500V max on the PV input you will be fine. The results you calculated shows that the voltage fluctuates more with temperature than current. Your accent sounds Australian but your calculations go down to -30°C... where are you located?

Thank you for answering.

I'm from Ukraine, We had this whole winter with blackouts(no power, internet, cell) and timed energy outages (10 days-3 hours power total it got worse it got better it was cycling) due to the russian invasion and strikes on civilian energy plants, so i went battery backup first, and installing solar for better usage. We are expecting outages even in summer and next winter can be really catastrophic

Gasoline generator is pain when you need power on constant basis, it is winter, my hot water pumps should be spining. And lots of liters of gasoline 3 canisters a day is a pain also

Edited April 28, 20233 yr by Denveronly

7 hours ago, Denveronly said:

my hot water pumps should be spining

I am sorry that you have to live through a hot war. It feels like we are living in the aftermath of a war (corruption) in South Africa, but I don't think it compares. Do you circulate hot water to prevent freezing? Are you close to 50°N? I can't advise you on snow but I can think that the energy yield will be quite low in winter and you will have to keep your batteries warm.

11 hours ago, Denveronly said:

Thank you for answering.

I'm from Ukraine, We had this whole winter with blackouts(no power, internet, cell) and timed energy outages (10 days-3 hours power total it got worse it got better it was cycling) due to the russian invasion and strikes on civilian energy plants, so i went battery backup first, and installing solar for better usage. We are expecting outages even in summer and next winter can be really catastrophic

Gasoline generator is pain when you need power on constant basis, it is winter, my hot water pumps should be spining. And lots of liters of gasoline 3 canisters a day is a pain also

Slava Ukraini