6 minutes ago, isie said:

Correct, if I add a panel or 2 more, that should increase the voltage and in turn would increase the power

Not two, you are already on 450V 😮

7 minutes ago, YellowTapemeasure said:

Not two, you are already on 450V 😮

Nah, my current voltage is on +-280V

4 hours ago, isie said:

Nah, my current voltage is on +-280V

OK, my bad. Early morning maths😁

On 2022/10/29 at 3:37 PM, FixAMess said:

Yes, makes sense.....It would be interesting to see the effect of not having the 2 strings balanced......

Not really buying the "strings have to be balanced thing" 

What happens when people only use one MPPT, that has to be the ultimate unbalanced? 

My 2c on this and from direct experience. I have an 8kw Magneto inverter (which is Deye). I have (had) 20x 455w with 49.5 VOC panels over both mppts in series. I ran into issues with over voltage and random irregularities with heat and current.

Since removing 1 panel from each mppt I no longer have issues and run nominally at between 380v and 420V with 9 panels per string in S.

Moral of the story, stick under the mppt listed voltage of 425v max. My electrician INSISTED that the installation would be fine since he ignored the 425v on the mppt spec and only looked at the 500v max rating of the PV supply overall. This 500v is for spikes from CEE. 

Edited November 4, 20223 yr by Gavin286
missed info

Thanks for all your input. In the end, I went with 2 x 5kW inverters giving me 4 separate MPPTs. I have 4 strings now, 2 facing north (8S each) and 1 facing east and west each (5S each).

Interesting trend, I am also looking at adding additional PV to one of my Sunsynk 8kw MPPT's. Any advice would be much appreciated, and if safe to do so.

Current setup of 11x 330W canadian (CS6U-330P) (1x 330W disconnected due to VDC limits) on one MPPT(1), and 9x 405 Canadian (CS3W-405P) on the other MPPT(2), all panels are connected in series.

I got 6x more 330W panels and would like to add them to the current 330W string. My plan would be as follow. Create two strings of 9x 330W on one MPPT(1) the other MPPT(2) will remain with the current 9x 405W (for now, do have one more 405W to add eventually 🙂 ).

Looking at the info on the 330W panels I should be below the MPPT rating for the Sunsynk, my concerns are more Watts and amps. Would unbalanced MPPT be ok, can the one MPPT(1) be at 5940W and the other at MPPT(2) 3645W.

2 strings of 9x 330W (voc 410,4)(isc 18,9) watt 5940

On the side sticker of the Sunsynk (SUNSYNK-8K-SG01LP1) its shows PV Input Current 18Ad.c+18Ad.c but believe that this is now 22Ad.c per MPPT. From my understanding this was changed in some firmware version not sure if this is the case. current code (COMM:E426 - MCU:6022-0717)

I need to be very careful with this investment. 🙂

4 hours ago, Fred79 said:

Interesting trend, I am also looking at adding additional PV to one of my Sunsynk 8kw MPPT's. Any advice would be much appreciated, and if safe to do so.

Current setup of 11x 330W canadian (CS6U-330P) (1x 330W disconnected due to VDC limits) on one MPPT(1), and 9x 405 Canadian (CS3W-405P) on the other MPPT(2), all panels are connected in series.

I got 6x more 330W panels and would like to add them to the current 330W string. My plan would be as follow. Create two strings of 9x 330W on one MPPT(1) the other MPPT(2) will remain with the current 9x 405W (for now, do have one more 405W to add eventually 🙂 ).

Looking at the info on the 330W panels I should be below the MPPT rating for the Sunsynk, my concerns are more Watts and amps. Would unbalanced MPPT be ok, can the one MPPT(1) be at 5940W and the other at MPPT(2) 3645W.

2 strings of 9x 330W (voc 410,4)(isc 18,9) watt 5940

On the side sticker of the Sunsynk (SUNSYNK-8K-SG01LP1) its shows PV Input Current 18Ad.c+18Ad.c but believe that this is now 22Ad.c per MPPT. From my understanding this was changed in some firmware version not sure if this is the case. current code (COMM:E426 - MCU:6022-0717)

I need to be very careful with this investment. 🙂

The Amps are okay. The 18A or 22A DC relates to the maximum operating current, which in your case is 2x8.88A.

The inverter's maximum Isc it can handle is much higher, around 44A. Using this link as a reference SUN-5/6K-SG01LP1-US SUN-7.6/8K-SG01LP1-US/EU | 5-8kW | Single Phase | 2 MPPT | Hybrid Inverter | LV Battery Supported Inverter Company, Supplier | Deye Inverter Technology but I'm not able to comment on the differences between inverter versions, I'm just saying you should be fine on Amps.

It's fine to have the MPPTs unbalanced, but what I'm not sure of is whether MPPT1 can go over 5200W. On my 5kW the spec is that each MPPT carries 50% of the max.

Edited October 27, 20232 yr by GreenFields

On 2022/10/29 at 12:25 PM, Sc00bs said:

Hi @mneeth

10400w is the maximum DC power that the inverter can produce, it is not a limit to the amount of panels you can put on the inverter.

The inverter can produce a maximum of 8.8kw of AC power so any more than that produced will need to go into the batteries. 

Maximum Amperage the MPPT will use is 18A and maximum voltage is 425V, I would give the 425V limit a wide berth as panels can spike the voltage if they are very cold, you should be good at 385V so your North facing string is 385V x 18A = 6930Watts

You could either add extra panels to your East facing string if you wanted or maybe go for a higher amperage panel.

The big restriction on the MPPT's is the Voltage which you must be careful not to go above.  The inverter can control the amperage the panels produce by increasing the resistance in the inverter which reduces the amperage/power being produced. The inverter also reduces the power being generated from the panels when the batteries are full and there is no where for the power to go. The guys from Sunsynk talk about over watting the panels.

I have 12,740 watts of panels on my 8kw Sunsynk for example. 

Makes more power than I can use on high solar radiation days but most important thing is on overcast days it still makes enough power for us to charge batteries and cover all my day time usage. 

Hi Sc00bs,

 

Hope you´re still here!

I'm awaiting approval of my account, but i can't wait to ask about the above statement.

 

I am (very) close to finishing my pv setup, using a Deye 12 kW hybrid inverter. I'll over panel a bit more than recommended with a total of 16920 Wp all facing the same direction. this is around 41% more than the 12 kW, but only 8,5% more than the max pv input of 15600 W

Do you think that the inverter can handle this? you seem to actually know the working principles of the mppt's

Some say that it's not a problem, and others that it will kill the inverter

Please note that i am 100% sure that Voc and Isc is okay, also in coldest conditions. The only thing that's over limit is the wattage

 

Do your whole 12740 watt array point in the same direction?

 

Thanks in advance

Anders

 

35 minutes ago, Sigersen said:

Hi Sc00bs,

 

Hope you´re still here!

I'm awaiting approval of my account, but i can't wait to ask about the above statement.

 

I am (very) close to finishing my pv setup, using a Deye 12 kW hybrid inverter. I'll over panel a bit more than recommended with a total of 16920 Wp all facing the same direction. this is around 41% more than the 12 kW, but only 8,5% more than the max pv input of 15600 W

Do you think that the inverter can handle this? you seem to actually know the working principles of the mppt's

Some say that it's not a problem, and others that it will kill the inverter

Please note that i am 100% sure that Voc and Isc is okay, also in coldest conditions. The only thing that's over limit is the wattage

 

Do your whole 12740 watt array point in the same direction?

 

Thanks in advance

Anders

 

Need some info on how you are wiring your arrays and the panel specs. 

I have just bought an 8k Deye invetor and its power storage system. My electrician has install it with six solar panels facing North. Our challenge is that no power from the solar is received by the invertor. The panels are 4.6 kw . What are we suppose to do? Please assisst

U'Thant Siyo

22 hours ago, Chris_S said:

Need some info on how you are wiring your arrays and the panel specs. 

Jinko tiger neo 470

3 strings 12 panels each

2 of the strings parallel on one MPPT ant the 3rd string on the other MPPT.

Both Isc and Voc values are okay under all conditions, So it's only a matter of dc/ac ratio of the inverter that's a litle too high. 1,41 vs 1,3

STC-like conditions are relatively rare here in Denmark

 

Panels pointing 226 (46 degrees from optimum) and tilt is 20 degrees (18 degrees from optimum)

 

STC:

Voc 42,38V

Isc 14,15A

Vmp 35,05V

Voc coefficient -0.25%/℃

 

Panels 470 W: JKM460-480N-60HL4-(V)-F1-EN (IEC 2016).ai (elitag.dk)

Inverter 12 kW: 【B】30240303000040 服务指南 储能三相-SUN-(8-12)K-SG04LP3 Deye 彩印 157g铜版纸 英文单页 (elitag.dk)

 

Thank you

Edited November 29, 20232 yr by Sigersen
Optimum tilt edited

6 hours ago, Sigersen said:

Jinko tiger neo 470

3 strings 12 panels each

2 of the strings parallel on one MPPT ant the 3rd string on the other MPPT.

Both Isc and Voc values are okay under all conditions, So it's only a matter of dc/ac ratio of the inverter that's a litle too high. 1,41 vs 1,3

STC-like conditions are relatively rare here in Denmark

 

Panels pointing 226 (46 degrees from optimum) and tilt is 20 degrees (18 degrees from optimum)

 

STC:

Voc 42,38V

Isc 14,15A

Vmp 35,05V

Voc coefficient -0.25%/℃

 

Panels 470 W: JKM460-480N-60HL4-(V)-F1-EN (IEC 2016).ai (elitag.dk)

Inverter 12 kW: 【B】30240303000040 服务指南 储能三相-SUN-(8-12)K-SG04LP3 Deye 彩印 157g铜版纸 英文单页 (elitag.dk)

 

Thank you

For sure this informations needs some changes. 

Series string of 12 the Voc too high. 

 

5 hours ago, Scorp007 said:

For sure this informations needs some changes. 

Series string of 12 the Voc too high. 

 

Mppt Voltage range is up to 650 volt, and 12 panels are only 508 plus temperature coefficient (581 volt @ -32C)

what does your calculations say?

37 minutes ago, Sigersen said:

Mppt Voltage range is up to 650 volt, and 12 panels are only 508 plus temperature coefficient (581 volt @ -32C)

what does your calculations say?

My mistake. Was not aware that the MPPT range is 650V. Thought it was 500V.

1 minute ago, Scorp007 said:

My mistake. Was not aware that the MPPT range is 650V. Thought it was 500V.

No worries!

just glad it was not right, because the panels are already on my roof 😂

18 minutes ago, Sigersen said:

No worries!

just glad it was not right, because the panels are already on my roof 😂

How about placing the inverter spec label so that we can see the higher spec label on your 8kW inverter. 

18 minutes ago, Scorp007 said:

How about placing the inverter spec label so that we can see the higher spec label on your 8kW inverter. 

It’s a 12 kW deye. Link in my earlier post

29 minutes ago, Sigersen said:

It’s a 12 kW deye. Link in my earlier post

OK now I get it.

General over panelling input should be at about 30%, this is so you don't have to tinker with any repanelling when you have days that are less hot and panels are producing really high power. On the issue of balancing panels between the two Mppts, it's just a red herring by "some" installers. Just ensure you are within the right voltage and under by at about 50volts or so to protect the inverter and also ensure that there's correct PV protections put on your system. You'll rather have a fuse blow or breaker drop than inverter blow up.

3 hours ago, Moffat said:

General over panelling input should be at about 30%, this is so you don't have to tinker with any repanelling when you have days that are less hot and panels are producing really high power. On the issue of balancing panels between the two Mppts, it's just a red herring by "some" installers. Just ensure you are within the right voltage and under by at about 50volts or so to protect the inverter and also ensure that there's correct PV protections put on your system. You'll rather have a fuse blow or breaker drop than inverter blow up.

Thank you for your answer.

it sounds like I should be fine, even with slightly more than 30%. 
plenty of volts left before hitting max.

i have 20A bels automatic fuses on each string, to protect against short circuits on the parallel strings.

 

5 minutes ago, Sigersen said:

Thank you for your answer.

it sounds like I should be fine, even with slightly more than 30%. 
plenty of volts left before hitting max.

i have 20A bels automatic fuses on each string, to protect against short circuits on the parallel strings.

 

Normally isn't issue of volts measured in summer as temperatures are high and this causes the panels not to be as efficient, it's when you get cooler temperatures with plenty of sunshine where the worry then comes in hence the need to leave enough headroom for such days.

9 minutes ago, Moffat said:

Normally isn't issue of volts measured in summer as temperatures are high and this causes the panels not to be as efficient, it's when you get cooler temperatures with plenty of sunshine where the worry then comes in hence the need to leave enough headroom for such days.

I’m at 581 volt in coldest conditions ever recorded in this area, and inverter mppt supports up to 650, so I guess voltage is alright

I have 2 parallel strings on one mppt on a sunsynk 8kw.

220v 26A string. On a sunny day the inverter will clip the current at 20A but on a partly cloudy day with all the cloud Edge it was often shutdown the mppt for a few seconds or even trip the inverter with a DC overcurrent fault. 

Just don't over panel the current like I did. 

11 minutes ago, Chris_S said:

I have 2 parallel strings on one mppt on a sunsynk 8kw.

220v 26A string. On a sunny day the inverter will clip the current at 20A but on a partly cloudy day with all the cloud Edge it was often shutdown the mppt for a few seconds or even trip the inverter with a DC overcurrent fault. 

Just don't over panel the current like I did. 

A good reason why one could over panel for the 10 cloudy days a year but there is risk involved.